AN INVESTIGATION OF ARSENIC IN SPY POND
by
Kathryn J. MacLaughlin
B.S. in Civil Engineering
B.A. in History
Bucknell University, 1994
SUBMITTED TO THE DEPARTMENT OF CIVIL AND ENVIRONMENTAL
ENGINEERING IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF
MASTER OF ENGINEERING IN CIVIL AND ENVIRONMENTAL ENGINEERING
AT THE
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
JUNE 1999
@ 1999 Massachusetts Institute of Technology. All rights reserved
Signature of Author
LI)
(%
partment of Civil and Environmental Engineering
May 7, 1999
Certified by
James E. Gawel
Doctor of Civil and Environmental Engineering
Thesis Supervisor
Certified by
Harold F. Hemond
Professor of Civil and Environmental Engineering
Department Reader
Accepted by
Andrew J. Whittle
Professor of Civil and Environmental Engineering
Chairman, Committee for Graduate Studies
MASSACHUSETTS
OF
IWO
MAY 2 8
LIBRARIES
An Investigation of Arsenic in Spy Pond
by
Kathryn J. MacLaughlin
Submitted to the Department of Civil and Environmental Engineering
on May 7, 1999 in Partial Fulfillment of the
Requirements for the Degree of Master of Engineering in
Civil and Environmental Engineering
ABSTRACT
In early 1997, high concentrations of arsenic were discovered in the sediments of Spy
Pond in Arlington, Massachusetts. Further investigation revealed that the highest
concentrations of arsenic were closest to the surface of the sediments. Spy Pond is a
hypereutrophic lake with a residential-based catchment area draining into it.
A multi-pronged investigation of the source type and location of the arsenic
contamination was conducted including stormwater sampling, sediment sampling, catch
basin sampling, Geographic Information Systems (GIS) analysis and historical research.
With average concentrations of arsenic in Spy Pond's surface sediment samples around
500 ppm to 800 ppm, estimates of the total quantity of arsenic in the surface sediments
range from 1,200 to 1,920 kg. Contouring of the sediment sampling results identify a
concentration of arsenic in the North Basin of the Pond. Preliminary results indicate less
than 4 kg/yr of arsenic enters Spy Pond through the stormwater drainage system. Less
than 1 kg arsenic has been attributed to the historical use of pesticides. The result of this
study points towards a groundwater plume entering the Pond in the vicinity of the North
Basin.
Thesis Supervisor: James E. Gawel
Title: Doctor of Civil and Environmental Engineering
LIST OF FIGURES ..........................................................................................................
5
LIST OF TABLES ........................................................................................................
6
1. INTRODUCTION ......................................................................................................
7
1.1 SPY POND .......................................................................................................---
9
1.1.1 Spy Pond Limnology......................................................................................
13
1.2 THE W ATERSHED ..................................................................................
-..-------.........
1.3 GEOLOGY ..........................................................................................-
2. PREVIOUS STUDIES .............................................................................................
14
14
19
2.1 SEDIMENT SAMPLING WITHIN SPY POND ...............................................................
19
2.2 W ATER COLUMN CHEMISTRY ...............................................................................
2.3 DRAIN OUTFALL SAMPLING...................................................................................
23
28
3. STORMWATER AND SEDIMENT SAMPLING AND MAPPING.........30
3.1 INTRODUCTION ...................................................................................................
30
..---...-.--..
3.2 METHODS...................................................................................................3.2.1 Stormwater Sample Collection ......................................................................
3.2.2 Catch Basin Sample Collection......................................................................
3.2.3 Surface Sediment Sample Collection.............................................................
3.2.4 Stormwater Sample Preparationand Analyses .............................................
3.2.5 Energy DispersiveX-Ray Fluorometer(ED XRF) Sample Preparationand
A n a lysis.......................................................................................................................
30
30
31
33
33
3.3.1 Stormwater Sampling Results.........................................................................
3.3.2 Catch Basin Sampling Results......................................................................
3.3.3 Sediment Sampling Results.............................................................................
35
35
35
52
53
3.4 GEOGRAPHIC INFORMATION SYSTEMS (GIS)........................................................
58
3.4.1 GIS Software..................................................................................................
3.4.2 Data Sources..................................................................................................
3.4.3 Raw Analytical Data Layers...........................................................................
3.4.4 Derived DataLayers ......................................................................................
3.5 CONCLUSIONS .........................................................................................
3.5.1 Arsenic Loading to Spy Pondfrom Stormwater Runoff ................
3.5.2 Road Salt Runoff as a Potential Source.........................................................
3.5.3 PreliminaryQuantificationof Arsenic in Spy Pond.......................................
3.5.4 Mass Balance Calculations...........................................................................
58
58
61
61
62
62
64
64
66
3.3 RESULTS ..........................................................................................-.
.---.----.........
4. HISTORICAL INVESTIGATION.........................................................................
68
4.1 INTRODUCTION .........................................................................................................
68
69
69
75
76
4.2 M ETHODS AND DISCUSSION...................................................................................
4.2.1 Sanborn Fire Insurance Maps of Spy Pond..................................................
4.2.2 PresentDay Uses...........................................................................................
4.2.3 LiteratureReview ..........................................................................................
4.3 POTENTIAL ARSENIC SOURCES IN SPY POND ........................................................
3
79
79
80
80
83
83
........ 84
4.3.1 Ice Harvesting...............................................................................................
4.3.2 Market Gardening..........................................................................................
4.3.3 Treatment History of the Pond ......................................................................
4.3.4 Gypsy Moth Infestation..................................................................................
4.3.5 Other PotentialSources..................................................................................
4.4 CONCLUSIONS ........................................................................................
REFERENCES.................................................................................................................85
ACKNOW LEDGEM ENTS...................................................................87
4
List of Figures
1-1:
1-2:
1-3:
1-4:
1-5:
1-6:
1-7:
... ...... 8
Spy Pond Locus Map.....................................................
Spy Pond Bathymetry.......................................................................10
.... 11
....
Profile of Spy Pond........................................................
Spy Pond Drain Outfall Locations..........................................................12
...15
Spy Pond Watershed ..............................................
Spy Pond Landuse..................................................................16
..-17
Surficial Geology Spy Pond Region..................................................
2-1: Distribution of Arsenic in the Surface Sediments of the Alewife Brook and Mill
........ 20
Brook Watersheds.......................................................
2-2: Spy Pond Sediment Core...................................................................22
2-3: Change in Amount of Solid Material with Depth in Spy Pond Sediment Core.......22
2-4: Spy Pond Temperature vs. Depth.........................................................25
2-5: Spy Pond Dissolved Oxygen vs. Depth....................................................26
2-6: Spy Pond Arsenic vs. Depth..............................................................27
3-1: Timed Stormwater Sampling Data Sheet................................................32
3-2: Catch Basin Sediment Sampling Locations.............................................34
3-3: Stormwater Sampling 11/11/98 Nitrate and Sulfate Results..........................37
3-4: Stormwater Sampling 11/11/98 Drain 36 & 36A Phosphate Results...................38
3-5: Stormwater Sampling 11/11/98 Drain 20 Phosphate Results............................39
3-6: Stormwater Sampling 12/8/98 Nitrate and Sulfate Results............................41
3-7: Stormwater Sampling 1/24/99 Arsenic Results............................................43
3-8: Stormwater Sampling 1/24/99 Nitrate, Sulfate and Chloride Results...................44
3-9 Stormwater Sampling 1/24/99 Phosphate Results......................................45
3-10: Stormwater Sampling 2/18/99 Arsenic Results........................................47
3-11: Stormwater Sampling 2/18/99 Nitrate, Sulfate and Chloride Results..............48
3-12: Stormwater Sampling 2/18/99 Phosphate Results.......................................49
3-13: Drain 4 2/18/99 Phosphate, Nitrate, Sulfate and Chloride Results.................51
3-14: Arsenic Contours Surface Sediment Samples............................................54
3-15: Arsenic vs. Lead Surface Sediment Samples 12/11/98 and 2/19/99..................57
3-16: Arsenic as a Function of Chloride.........................................................65
3-17: Arsenic in Spy Pond.................................................................67
4-1: Spy Pond - 1900s................................................70
71
4-2: Spy Pond - 1910s........................................................
4-3: Spy Pond - 1920s.......................................................................72
... 73
4-4: Spy Pond - 1951............................................................
-...... 74
....
4-5 Spy Pond - 1971......................................................
5
List of Tables
1-1: Spy Pond B asins.............................................................................
9
2-1: Surface Sediment Sample Collection Summary........................................19
29
2-2: Drain Outfall Sampling July 1998.......................................................
36
3-1: Stormwater Sampling Results 11/11/98................................................
3-2: Stormwater Sampling Results 12/8/98..................................................40
42
3-3: Stormwater Sampling Results 1/24/99..................................................
3-4: Stormwater Sampling Results 2/18/99..................................................46
3-5: Stormwater Sampling Results 2/18/99 Drain 4 Sequenced Results..................50
3-6: Selected Catch Basin Sampling Results..................................................53
3-7: Sediment Sampling Results 12/11/98....................................................55
3-8: North Basin Sediment Sampling Results 2/19/99......................................56
60
3-9: G IS D ata Sources..........................................................................
3-10: Spy Pond Stormwater Runoff Loading Calculations.................................63
4-1: Summary of Weed Control in Spy Pond...................................................82
6
1. Introduction
In early 1997, Ivushkina collected sediment samples from Spy Pond (the Pond) as part of
an investigation of toxic elements in the sediments of the Alewife Brook and Mill Brook
Watersheds (see Figure 1-1) [Ivushkina, 1999]. The sediment samples were analyzed for
a number of trace metals, including arsenic. Unexpectedly, the results indicated
exceptionally high concentrations of arsenic in the Spy Pond's sediments. The discovery
of high concentrations of arsenic in the sediments prompted a number of studies
including, a water column investigation; sediment mapping; and the foci for this thesis,
stormwater monitoring, and a historical investigation of potential arsenic sources.
Compounds containing arsenic have been used for hundreds of years for medicinal
purposes and as a pesticide [National Research Council, 1977; Aurilio, 1992]. Despite
this history of medicinal use, arsenic is known to be acutely toxic to humans at high
doses [International Agency for Research on Cancer, 1980; Aurilio, 1992]. Strong
epidemiological evidence also shows that some forms of arsenic are carcinogenic
[International Agency for Research on Cancer, 1980; Aurilio, 1992]. Background arsenic
concentrations of 0.4 to 40 mg/kg are considered typical for soils with no natural or
anthropogenic arsenic inputs [National Research Council 1977; Aurilio, 1992].
Arsenic concentrations in surface sediment samples in Spy Pond, however, are generally
above 500 ppm, with a maximum concentration of 2,650 ppm. Although the
Environmental Protection Agency (EPA) has not adopted maximum concentration limits
(MCL) for sediments, they currently use Ontario Ministry of the Environment standards
of 30 ppm for arsenic. Additional studies focusing on possible ecological effects and
human exposure may be warranted. Finally, it should be noted that dredging the Pond
has been considered as a possible solution to improve the degraded conditions of the
Pond. Removing the arsenic-laden sediments from the Pond would involve treating them
as hazardous materials, according to regulations promulgated by EPA and Massachusetts
Department of Environmental Protection (MADEP).
7
Spy Pond Locus Map
Source: MassGIS 1:25,000 scale
Community Boundaries Datalayer, 1991
and 1:25,000 Hydrography Datalayer.
Figure 1-1
8
1.1 Spy Pond
Spy Pond (42' 24' 30"N, 71' 9' 19" W) is a 39.8-hectare kettle-hole pond with a surface
level 9 meters above mean sea level (MSL) in the town of Arlington, Massachusetts,
about 12.9 kilometers northwest of Boston (see Figure 1-1)[MassGIS, 1998]. The pond
has a volume of 1.43 million cubic meters with a maximum depth of 11+ meters and an
average depth of 4 meters [Massachusetts Division of Fisheries and Wildlife; MassGIS,
1998]
The pond is split into two distinct basins by Elizabeth Island (14,620 meters squared, m2
and a relatively shallow sill (water depth of less than 2 m). The North Basin is
considerably larger and deeper than the South Basin (see Table 1-1 and Figures 1-2, 1-3)
[MassGIS, 1998]. The bottom consists of sand overlain by deep muck deposits
[MacLaughlin, 1998; Massachusetts Division of Fisheries and Wildlife].
Table 1-1: Spy Pond Basins
North Basin
South Basin
(M )
235,956
171,432
Perimeter (m)
2,199
1,941
11+
6+
Area
2
Maximum Depth (m)
Note: areas and perimeters calculated using Arcview 3.1
Although Spy Pond has no natural inlet, a total of 43 drains empty into the pond, 40 of
which are municipal storm drains (see Figure 1-4) [MacLaughlin, 1998; Chesebrough and
Duerring, 1980]. During this investigation of the Pond, the author noted only one drain,
Drain 20, has dry weather base flow. Drain 20 drains the largest portion of the watershed,
Figure 1-2 Spy Pond Bathymetry
9
Bathymetry
Bathymetry
Figure 1-2
Source: Mass GIS 1:5000 scale Black & White Digital Orthophoto Images
Massachusetts Fisheries, Wildlife & Environmental Law:Fisheries & Wildlife Division Bathymetry
A-A' Profi le
0
0
0
Q)
C4
0
4
C1)
LCO
0)
Distance
(m)
Figure 1-3
Profile of ~Spy Pond
Storm Drain
Outfall Locations
Figure 1-4
Source: Arlington Department of Public Works record drawvings and Chesebrough and Duemrng (1982)
as well as directs flow from Hills Pond located in Menotomy Rocks Park to Spy Pond to
help maintain a constant water level in Spy Pond. The remainder of the drains flow
during wet weather and carry urban runoff into the pond.
The outlet from Spy Pond is a rectangular standpipe with wooden flashboards located in
the south corner. From the standpipe, Spy Pond's overflow enters a large culvert and
flows about 300 m underground, and then enters Little Pond. From here the water flows
into Alewife Brook [Shanahan, 1997].
1.1.1 Spy Pond Limnology
Spy Pond is a dimictic lake and, depending on the season, shows a particular temperature
and dissolved oxygen profile. During the summer season, the epilimnion, or warm
surface water, occupies the top zone and is well mixed by wind action. Below this is a
metalimnion that is characterized by a thermocline, the zone of rapid temperature change
with depth. The bottom waters, or hypolimnion, contain colder waters that tend not to
circulate nor replenish oxygen. During the spring and fall, these regions break down due
to temperature change and the entire lake circulates as one body. A high level of
productivity in the surface waters often results in low concentrations of oxygen in the
bottom-waters. This is the case for Spy Pond [Chesebrough and Duerring, 1982].
Spy Pond is a hypereutrophic lake, meaning it has depleted oxygen levels and an
overabundance of aquatic weeds. Eutrophication is a normal lake degradation process
that occurs at a slow rate under natural conditions. This process is accelerated by the
addition of excessive nutrients, especially nitrates and phosphates, into lakes and ponds.
The hypolimnion becomes anoxic during summer stratification and water transparency is
very low.
13
1.2 The Watershed
The 340-hectare Spy Pond watershed lies within the Mystic River Basin and is divided
between the towns of Arlington and Belmont (see Figure 1-5) [MassGIS, 1998].
Approximately 73 percent of the watershed is in Arlington and 27 percent is in Belmont
[Ivushkina, 1999]. Route 2, an 8-lane state highway, abuts the southwest shore of the
South Basin of Spy Pond and forms the division between Arlington and Belmont
[MassGIS, 1998]. The entire watershed of Spy Pond, with the partial exclusion of
Menotomy Rocks Park (a small park to the west of Spy Pond), is serviced by a
stormwater collection system that empties into the Pond.
The watershed is defined by steep slopes to the northwest (Arlington Heights, Menotomy
Rocks) and flat terrain to the east and southeast. With the exception of Menotomy
Rocks, the entire area is developed, mainly as single- and multiple-family homes (see
Figure 1-6).
The watershed has an average annual temperature of 10 degrees Celsius, a mean annual
precipitation of 110.2 cm, and the average snowfall is 1.3 m [Logan International Airport
Data, 1999].
1.3 Geology
Spy Pond is located within an area known as the "Fresh Pond Buried Valley." This is a
deep sediment-filled bedrock valley that extends from the town of Wilmington
southeastward to Boston Harbor (see Figure 1-7). This geologic feature underlies Halls
Brook Holding Area, Woburn; Wedge Pond, Winchester; the Mystic Lakes, Winchester
and Arlington; Spy Pond, Arlington; Fresh Pond, Cambridge; and the Aberjona River. A
thin, discontinuous layer of till covers the highlands bordering the buried valley while
stratified deposits predominate in the valley itself. The northeast portion of Spy Pond lies
along the central axis of the buried valley.
14
F~I44~
tU,
1
2
3
4
405,289
213,481
133,582
163,607
3,627
2015
1,756
1,661
5
194,829
2227
6
163,658
7
1,570,760
1,693
6,108
8
115,102
2,081
9
45,583
1,026
10
315,637
2,465
11
23,236
12
SA430
644
10s0
Figure 1-5
\0
0
&~~
e
bounda
jorabost
m Town
Landuse Clmmifcations
Puncip~um Roc..don
SPY
.,...,.,nr....ln
too0.20 2 lre
-\
Reeidbntll ->3.2 hAm~r
\
Spydnd
-Lnduse
--.
FgurbnOpen
Traportedon
---s
-
Spy Pond
000
Landuse
-eFigure 1-6
Source: MassGIS statewide 1:25,000 21 -category landuse classifications interpreted from 1:25,000
scale aerial photography taken 1971, 1985 and in some areas 1990 or 1991/1992.
Street lines are combined linework of MassGIS 1:100,000 scale roads datalayer
and supplemental linework provided by Massachusetts Highway Dept.
[
II
a
ii
I
Surnm an
c
Co.4b4a ,*~
/
swamp dp.wcA
.
ut#ft
h
,.
&
E
e
e
2
iW144E Zd sa~md -4
Figure 1-7
Surficial Geology Spy Pond Region
17
Igneous outcrops are common to the northwest of the lake in and around Menotomy
Rocks. The soil of the eastern and southern section of the pond's watershed is composed
primarily of sand, gravel, and clay. The depth to bedrock here is about 50 meters. The
land between Spy Pond and Fresh Pond was once all a swamp known as "the Great
Swamp." The land has been filled artificially and reworked over hundreds of years to
make it "usable" land [Shanahan, 1997].
18
2. Previous Studies
2.1 Sediment Sampling within Spy Pond
To determine the kinds and amounts of inorganic elements of public concern present in
the Alewife Brook and Mill Brook watersheds, Ivushkina and Durant performed an
investigation of surface sediments in 1997. Three surface sediment samples, one from
the North Basin and two from the South Basin of Spy Pond were collected as part of the
study. The samples were collected at depths of 4 to 5 meters in the South Basin and 8
meters in the North Basin using a 0.125 ft3 Ekman Dredge. The sediment samples were
analyzed using Instrumental Neutron Activation Analysis (INAA). A summary of the
results is shown in Table 2-1 [Ivushkina, 1999].
Table 2-1
Surface Sediment Sample Collection Summary
[Data from Ivushkina, 1999]
Sample No.
SPSS
SPSS2
SPNS
Depth
4-5 meters
4-5 meters
8 meters
Location
South Basin
South Basin
North Basin
Arsenic
69 ppm
860 ppm
300 ppm
Arsenic concentrations found in water bodies other than Spy Pond range from 73 ppm
(Lower Mystic Lake) to 10 ppm (Mystic River). Concentrations of arsenic in surface
sediment samples within the Alewife Brook and Mill Brook watersheds are shown in
Figure 2-1.
Overall, Spy Pond's sediments were representative of an urban environment, having
elevated concentrations of metals. However, analyses of these sediments revealed
inordinately high concentrations of arsenic, as well as selenium and lead [Ivushkina,
1999].
19
0.5
Niorth
05
1 ile
1k
I
t0
My=
k-
LUnkre
Source: Ivushkina, 1999
Distribution of Arsenic in the Surface Sediments
of the Alewife Brook and Mill Brook Watersheds
Figure 2-1
20
Following the Spy Pond surface sediment results, a 1-meter deep sediment core sample at
the deepest point (11 meters) within the North Basin of Spy Pond was collected on
January 30, 1998 [Ivushkina, 1999]. Arsenic concentrations were measured with depth
using INAA. The results of this analysis are given in Figure 2-2. The concentration of
arsenic was highest in the top 20 cm of the core, varying from 310 to 510 ppm. At depths
greater than 20 cm, arsenic concentrations drop to between 13 and 91 ppm [Ivushkina,
1999].
One interpretation of the sediment core results suggests that a major event in the
depositional history of sediments in Spy Pond might have been the 1968 filling of 2
hectares in the southwest end of the South Basin for the expansion of Route 2. The
expansion involved the removal and redistribution through the Pond of all organic matter
from the 2 hectares [Cortell, 1973; Senn, 1998]. This, along with the vibration associated
with heavy construction may have caused a large increase in sediment deposition in a
short time. Some 15 to 30 cm of sediment may have been deposited over the course of
several months as a result of the filling [Cortell, 1973]. This deposit may explain
observations of an approximately 40 cm section of the sediment core which is highly
enriched in crustal material and has a substantially higher percent solid ratio than the rest
of the sediment core (see Figure 2-3) [Senn, 1998]. If the "bulge" in percent solids from
15 to 50 cm can be attributed to the extension of Route 2 in 1968, then the sediment
depositional rate can be estimated as approximately 0.5 cm per year (15 cm accumulated
from 1968 to 1998).
Several theories have been postulated to explain the core sample's arsenic profile. One
interpretation is the major increase in arsenic concentrations began around 1968 (-45 cm
depth) and continues to today, suggesting that the source still injects arsenic into the
pond. Another possible explanation is arsenic inputs began at 60 cm (approximately
1940s using 0.5cm/yr depositional rate) depth and the rapid sediment deposition that
occurred with the filling of the Pond "diluted' the concentrations of arsenic during that
period. This event caused a low concentration arsenic profile from 45 cm to 20 cm depth.
21
Figure 2-2: Spy Pond Sediment Core
Figure 2-3: Change inAmount of Solid Material
with Depth inSpy Pond Sediment Core
Arsenic (ppm)
0
100
200
300
400
500
600
Change in Percent Solid Material (%)
0
0
0
20
10
20
40
t")
30
E
0.
E
60
40
2
50
(D
o'
60
80
70
100
80
90
1201
100
5
10
15
20
The same source from 60 cm then "reappears" in the profile above 20 cm depth and
continues to input arsenic to the Pond today. Finally, a possible explanation for the
arsenic profile is the Pond's hypereutrophic condition. Arsenic has a tendency to be
remobilized within the sediment during anoxia potentially resulting in the continual
upward mobilization of arsenic. This interpretation of the sediment core profile suggests
that a past input of arsenic may be migrating towards the sediment-water interface (see
Section 4-2) [Harrington, 1998].
Lead-210 dating of the core has yet to be performed and may reveal new information on
sedimentation rates. A possible alternative to accurately date the core sample is to further
investigate the source of a sharp spike in copper concentration at approximately 10 cm
depth.
The sediment core sampling results indicate a strong correlation between arsenic,
chloride, and selenium. These chemical associations indicate the potential source of the
contamination is from road runoff, specifically runoff concentrated with road salt, into
the Pond. This correlation implicated runoff from runoff from Route 2 as a potential
source of high levels of arsenic in Spy Pond [Senn,1998; Ivushkina,1999].
2.2 Water Column Chemistry
In the summer of 1998, Senn and Gawel began collecting water column data from the
North and South Basins of Spy Pond to observe trends in arsenic concentrations and
speciation as well as monitor other constituents in the water. Samples were collected
biweekly until October, when sampling was increased to every week in order to capture
the Pond's seasonal turnover (loss of thermocline). As of this writing, water column
sampling continues. For each sampling date, water samples are collected from a
designated location in the center of the North Basin at depths ranging from 1 to 10
meters. Samples are also collected from a designated central location in the South Basin
at depths ranging from 1 to 6 meters. Representative data from two sampling dates for
23
temperature, dissolved oxygen, and total arsenic are shown in Figures 2-4 through 2-6
[Senn and Gawel, 1999].
The amount of oxygen in Spy Pond is relevant because it influences arsenic cycling.
Arsenic predominately occurs in the oxidized pentavalent state as arsenate (As(V)) or in
the reduced trivalent state as arsenite (As(III)). The depletion of oxygen in the bottom
waters initiates the remobiliztion of arsenic from the sediments to the water column.
Under highly reducing conditions (as evidenced by the presence of sulfide), arsenic has
been observed shifting from As(V) to As(II) [Spliethoff, 1995]. The biological
availability and physiological and toxicological effects of arsenic depend on its chemical
form. As(III) is much more toxic, more soluble, and more mobile than As(V) [Nriagu,
1994].
The water column study results show a thermocline forms at -4 meters in both the North
and South Basins in the summer. The thermocline erodes in both basins in late fall, with
the shallower South Basin turning over before the North Basin [Senn and Gawel, 1999].
Bottom waters of Spy Pond during stratification are anoxic and highly reducing, as
evidenced by the presence of sulfide. These conditions allow for the remobilization of
arsenic from the sediments to the water column and the predomination of As(I) (results
not shown). Preliminary evidence suggests the As(III) may reoxidize with the turnover
of the Pond, bind to particles, and settle into the sediment again [Senn and Gawel, 1999].
The remobilization of arsenic in a highly toxic state may have some significance for the
recreational use of Spy Pond. Traditionally, the EPA has considered toxic metals in
sediments to be of minimum concern because they are difficult to remobilize. However,
in extremely reducing and anoxic conditions, like Spy Pond, arsenic may be reduced to
its more toxic, soluble form and released to the overlying waters [Senn and Gawel, 1999].
24
North Basin
South Basin
Temperature (C)
0.00
10.00
20.00
Temperature (C)
30.00
0.00
0-
0-
2
1
E
3-
-4-8/17
6
--
CL
30.00
10/27
+-8/17
c24
0-4
8
10
20.00
2
4(A
10.00
5
W
12 -
6
7
Source: Senn and Gawel, 1999
Figure 2-4
Spy Pond
Temperature vs. Depth
South Basin
North Basin
Dissolved Oxygen (mg/L)
Dissolved Oxygen (mg/L
0.00c
5.00
10.00
0.00
0
15.00
0-
5.00
10.00
15.00
2
2
4
-+--
E
6
E3
-*-8/17
-A-
-A- 10/27
0. 4
4)
0
8/17
8
5
10
6
12
7
Source: Senn and Gawel, 1999
Figure 2-5
Spy Pond
Dissolved Oxygen vs. Depth
10/27
South Basin
North Basin
Total Arsenic, unfiltered (nM)
0.00
100.00
200.00
Total Arsenic, unfiltered (nM)
300.00
0.00
0
0-
2
1
E
-+-8/17
6
CL
-A- 10/27
a)
0
8
E 3
CL
4
1000.00
2000.00
-+-
8/17
-A- 10/27
5
10-
6
12
7
Source: Senn and Gawel, 1999
Figure 2-6
Spy Pond
Arsenic vs. Depth
2.3 Drain Outfall Sampling
Preliminary drain outfall sampling, conducted over a period of three field sessions in
July, 1998, revealed the presence of arsenic in low concentrations in stormwater runoff
entering the Pond [Gawel, 1998]. Drain 36A, which drains a portion of Massachusetts
Avenue, showed the highest concentration of arsenic (9.9 ppb), while other drain samples
showed trace amounts. A summary of the results is in Table 2-2 (see Figures 1-2 and 1-4
for watershed boundaries and drain locations). Initial sampling results indicate
potentially significant amounts of arsenic entering the Pond via the stormwater drainage
system, however further sampling and investigation is necessary to define the impact of
the stormwater drainage system on total arsenic loads.
28
Table 2-2
Drain Outfall Sampling
July 1998
[Data from Gawel and Chin, 1998]
29
3. Stormwater and Sediment Sampling and Mapping
3.1 Introduction
The overall goal of this thesis work was to locate and define potential sources for the
elevated levels of arsenic found in Spy Pond sediments. Past investigations have
prompted the author to further explore the potentially significant arsenic input of 43
storm drain outfalls carrying urban runoff into the Pond. Based on a strong correlation
between arsenic and chloride, road salt entering the Pond via runoff was investigated as
another potential source. Also, drains which carry stormwater runoff from Massachusetts
Avenue were targeted because preliminary stormwater sampling indicated rather high
concentrations of arsenic in Drain 36A. Furthermore, Massachusetts Avenue is the only
commercial area in Spy Pond's watershed.
The sampling strategy had a multi-pronged approach.
1. Determine the amount and location of arsenic entering Spy Pond via the stormwater
drain system.
2. Establish a more accurate quantification of the total amount of arsenic in Spy Pond
sediments through intensive surface sediment sampling.
3.
Analyze and interpret the results using Geographic Information Systems (GIS)
mapping and establish a preliminary mass balance for arsenic in Spy Pond.3.2
Methods
3.2.1 StormwaterSample Collection
Stormwater sampling is the collection of grab samples from stormwater drains flowing
into the pond during a rain event. Two sampling methods were employed for Spy Pond.
1. Time-sequenced samples were collected at one location over a period of 2 or more
hours.
"
November 11, 1998
"
December 8, 1998
*
February 18, 1999
30
2. Grab samples were collected at various locations around the pond.
" January 24, 1999
e
February 18, 1999
An example of the data sheet used for the time-sequenced samples is included in Figure
3-1.
The majority of samples were collected by directly placing a 15 ml plastic vial (acidwashed using 1 M HCl) into the storm runoff streamflow coming from the drain outfall.
Some samples were collected using an ISCO autosampler programmed to collect 12
samples at specific times over a period of 2 hours. Samples collected by the autosampler
were placed automatically into 1-liter plastic containers cleaned using soap and reverse
osmosis (R.O.)-treated water. All samples were immediately put on ice in the field and
transferred to a refrigerator at 4'C for storage prior to analysis.
3.2.2 Catch Basin Sample Collection
To fully understand the stormwater collection system's influence on arsenic and other
contaminants within the Pond, the author conducted sampling of sediments from 11 catch
basins around Spy Pond on April 12, 1999. Samples were collected at selected catch
basins elected to represent sediment from the entire watershed.
31
Spy Pond Storm Sampling
Drain Number:
Samplers:
Date:
Weather:
Sample No.
Sample
Real
Time (min)
Time (hr:min)
fl (Rtc~ 9 nnI~A
0 00
1
0.30
2
5.00
3
10.00
4
15.00
5
20.00
6
25.00
7
30.00
8
45.00
9
60.00
10
90.00
11
120.00
Temp
pH
Notes:
1
Figure 3-1
Timed Stormwater Sampling
Data Sheet
Samples were collected in 125 ml acid-washed (1 M HCl) plastic jars. Sample locations
are shown in Figure 3-2.
3.2.3 Surface Sediment Sample Collection
Surface sediment samples were collected using a Russian Corer and a 0.125 ft3 Ekman
Dredge on two dates, November 18, 1998 and February 19, 1999. Sample locations were
recorded using a Trimble GPS unit with a differential correction unit to measure the
geographic coordinate location of the sample. To collect sediments near the shore (water
0.75 m to 1.35 m deep), the researchers waded into the Pond and used a Russian Corer to
collect sediment at soil depths ranging from 0 cm to 33 cm. The remainder of the
samples were aquired using the Ekman Dredge from a boat to collect the top 20+ cm of
sediment at each specified location.
All samples were transferred to 125 ml acid-washed (1 M HCl) plastic jars using a
stainless steel spoon. The dredge and spoon were rinsed with surface pond water
(having arsenic concentrations <200 ppb)between sample locations. Sediment samples
were stored on ice in the field.
3.2.4 Stormwater Sample Preparationand Analyses
Stormwater samples were analyzed for total arsenic, sulfate, nitrate, chloride, and
phosphate. Sulfate, nitrate, chloride and phosphate samples were analyzed within 1 week
of collection.
Total arsenic was measured using a Graphite Furnace Atomic Absorption Spectrometer
(GF-AAS). Samples were acidified with 5 percent nitric acid (5 mls concentrated HNO 3
added to 95 ml sample) and allowed to equilibrate overnight. Five-point calibration
curves were established at the beginning of each analysis run. The curve was quality
assured for stability every 6 to 10 samples. The author measured phosphate using the
Stannous Chloride Method (Standard Method #424E). Nitrate, sulfate, and chloride were
33
Catch Basin
Sediment Sampling
Locations
Figure 3-2
Source: Arlington Department of Public Works record drawings and Chesebrough and Duerring (1982).
measured by ion chromatograph with an attached chart recorder. Five-point standard
calibration curves were run each day and checked after every 5 samples.
3.2.5 Energy Dispersive X-Ray Fluorometer(ED XRF) Sample PreparationandAnalysis
Within 12 hours of collection, the samples were placed into a drying oven at 80'C for 5
days, or until dry. Once dried, 4 grams of sediment were placed in a stainless steel
cylinder with a ball bearing and ground for 5 minutes using a mixer/mill (SPEX
CertiprepMixer/Mill 8000). Then, 0.90 gram of binder was added and the sample was
homogenized again for 1 minute. Once the sample was fully ground and homogenized, it
was pressed into a pellet using a hydraulic press at 20 metric tons for 1 mintue. All
equipment was cleaned thoroughly between samples.
An Energy Dispersive X-Ray Fluorometer (ED-XRF) was used to analyze for a full suite
of elements in the catch basin sediment samples and the surface sediment samples from
Spy Pond. Instrument accuracy was confirmed using both San Joaquin soil NISTcertified standard materials (SRM #2709) and Spy Pond samples spiked with known
concentrations of arsenic.
3.3 Results
3.3.1 Stormwater Sampling Results
Stormwater sampling results are included in Tables 3-1 to 3-5 and Figures3-3 through 313. Several aspects of the nature of the urban runoff were discovered through the
sampling. The time-sequenced samples show a definite "first flush" was captured on
December 8, 1998 and February 18, 1999. A first flush is the high loading of nutrients
such as nitrate, sulfate, and phosphate, that flows into the Pond with the storm runoff as
urban pollution is mobilized by the rain. However, the timed samples do not show any
variations in arsenic concentrations consistent with changes in nutrient loading. Since the
GF-AAS is only accurate to ±2 ppb, many of the arsenic measurements are not
35
Table 3-1
Stormwater Sampling Results 11/11/98
Drain 36A
Drain 36
Drain 20
Drain 19
Time
Nitrate
Sulfate
Phosphate
Arsenic
(min)
0.5
5
10
15
20
25
30
45
60
90
120
0.5
5
10
15
20
25
90
0
0.5
5
10
15
20
25
30
45
60
90
120
0
(ppm)
0.8
0.8
0.8
0.7
0.6
0.6
0.6
0.6
0.6
0.5
0.6
0.5
0.5
0.5
0.4
0.4
0.4
0.4
6.3
0.9
0.9
0.5
0.9
0.9
1.9
1.2
0.8
0.9
1.2
1.9
0.8
(ppm)
2.2
2.2
2.1
2.0
1.8
1.8
1.8
2.0
1.8
1.8
1.9
1.6
1.6
1.5
1.2
1.1
1.1
1.1
18.8
2.9
2.9
2.7
2.7
2.7
2.7
2.4
2.3
2.6
3.7
3.5
1.1
(mg P04-P/L)
0.293
0.311
0.284
0.255
0.250
0.257
0.259
0.256
0.348
0.267
0.316
0.330
0.345
0.325
0.248
0.242
0.225
0.222
0.042
0.444
0.622
0.600
0.585
0.514
0.497
0.429
0.489
0.543
0.397
0.473
0.042
(ppb)
1
1
1
0.5
0.5
1.5
0
0
0
0
0.5
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Note: Although two significant digits are shown for all arsenic concentrations, the GF-AAS
is only accurate to 2 ppb
36
Sulfate 11/11/98
4.0
3.5
3.03
E2.5
2.0
(U(
1.5
0.0
1.00.5
.0
20
0
60
40
Time (min)
80
100
120
140
Nitrate 11/11/98
36
7.0
6.00.0
5.0
36
200
200
20
1 -
3
10
0
20
40
80
60
100
120
140
Time (min)
Figure 3-3
Stormwater Sampling
11/11/98
Nitrate and Sulfate Results
37
Drain 36A: Phosphate 11/11/98
North Basin
0.000 0.050 0.100
0
0
a.
o>
0.150 -
0.200 3
S0.250
0.
IA
5 0.300
0.35
0.400
40.0
20.0
0.0
80.0
60.0
120.0
100.0
140.0
Time (min)
Drain 36: Phosphate 11/11/98
South Basin
--
0.000.
----
0.050
0
0.100-
a- 0.150-
drain stopped flowing
0)
E 0.200
0.2500.
M)
CL
0.3000.3500.f400
0.0
10.0
20.0
30.0
50.0
40.0
60.0
70.0
80.0
90.0
100.0
Time (min)
Figure 3-4
Stormwater Sampling
11/11/98
Drain 36 & 36A
Phosphate Results
38
Drain 20: Phosphate 11/11/98
0.700
-
0.600
0.500
0
0 0.400
co
0
MU
0.300
C.
0.200
0.100
0.000
-
0.0
20.0
40.0
80.0
60.0
100.0
120.0
140.0
Time (min)
Figure 3-5
Stormwater Sampling
11/11/98
Drain 20
Phosphate Results
Table 3-2
Stormwater Sampling Results 12/08/98
Drain 36A
Drain 36
Drain 20
Time
Nitrate
Sulfate
Arsenic
(min)
0.5
5
10
15
20
25
30
45
60
90
120
0.5
5
10
15
20
25
30
45
60
90
120
0
2
3
8
18
33
53
78
108
153
(ppm)
10.1
6.3
1.9
2.3
2.0
1.1
1.5
0.8
0.7
0.7
0.7
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
4.7
4.9
4.7
4.8
4.7
3.6
1.4
0.9
1.2
1.6
(ppm)
15.6
14.6
8.5
9.9
7.0
3.9
4.3
2.6
2.3
2.5
2.6
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
16.6
16.4
15.1
15.5
15.4
25.1
5.6
2.0
3.3
4.4
(ppb)
2.5
2
1
0
0.5
0
0
1
0
0
1
1
2
1.5
1.5
3.5
1
1.5
0.5
0
0.5
NA
0
0
0
0
0
0
0
0
0
0
NA = Not Available
Note: Although two significant digits are shown for all arsenic concentrations, the GF-AAS
is only accurate to 2 ppb
40
Sulfate 12/8/98
30.0
25.0
E 20.0
CL15.0
Co
10.0
5.0
0.0
0
20
40
60
100
80
120
140
160
180
Time (min)
Nitrate 12/8/98
12.0
10.0
a
CL
e
8.0
6.0
U
4.0
2.0
0.04!
0
I
20
I
40
I
60
I
100
80
Time (min)
120
140
160
180
Figure 3-6
Stormwater Sampling
12/8/98
Nitrate and Sulfate Results
41
Table 3-3
Stormwater Sampling Results 1/24/99
Collected 11:30 am to 2:30 pm
Drain
Nitrate
Sulfate
Phosphate
Chloride
Arsenic
Outfall
(ppm)
(ppm)
(mg P04-P/L)
(ppm)
(ppb)
1
3
4
5
6
8
9
10
11
13
0.0
0.4
0.5
0.0
0.0
0.2
0.1
0.1
0.0
0.1
2.1
1.0
2.8
0.8
1.1
1.1
0.6
0.8
1.4
1.7
0.246
0.633
0.163
0.205
0.211
0.313
0.896
0.986
0.247
0.123
8.1
12.1
20.6
16.1
18.5
28.2
22.8
15.5
40.0
41.3
6
10
2.5
5
6
4
1.5
1
1.5
0
19
0.0
0.7
0.186
19.1
1.5
20
21
22
23
24
25
30
31
35
36
36A
37
0.7
0.0
0.3
0.0
0.3
0.0
7.5
0.2
0.5
0.4
0.3
NA
3.4
1.7
2.3
0.0
3.3
1.5
4.4
3.1
3.8
2.6
2.9
NA
0.203
0.237
0.423
0.132
0.184
0.27
0.165
0.288
0.171
0.74
0.193
0.198
95.8
37.7
64.8
5.6
73.2
19.7
17.8
16.1
18.7
22.3
46.3
30.3
1.5
3
2
0
3.5
5
0
3
0.5
1.5
1.5
3
NA = Not Available
Note: Although two significant digits are shown for all arsenic concentrations, the GF-AAS
is only accurate to 2 ppb
42
CL
F
E
C*D
I
a
r:
a
SI
.3
ih
t
;
~
~
a0)
D
P
-wo
O
co
00
JI
co
C'',
j
43
002M
Chloride 1/24/98
100.0
90.0
80.0
70.0
'
0. 60.0
.8
_
6
50.0
40.0
30.0
20.0
10.0
0.0
Drain No.
Nitrate 1/24/98
8.0
7.0
6.0
E
0. 5.0
4.0
z
3.0
2.0
1.0
0.0
Drain No.
Figure 3-8
Stormwater Sampling
1/24/98
Nitrate, Sulfate, and Chloride Results
44
Figure 3-9: Stormwater Sampling 1/24/99
Phosphate Results
3.500
9
3.000
-
3
2.500-
36
0 2.0000)
E
10
*~1.500-
0.
0
0.
1.000
-
22
11
0.500
-
19
20
13
4
8
24
31
36A
25
37
0.000
Drain Number
Table 3-4
Results 2/18/99
Sampling
Stormwater
Sulfate
Nitrate
Drain
Phosphate
Chloride
Arsenic
(ppb)
0.5
1
0
4
2.5
9.5
Outfall
Date
Time
(ppm)
(ppm)
(mg P04-P/L
(ppm)
4*
5*
1
2
3
3A
2/17/99
2/17/99
2/18/99
2/18/99
2/18/99
2/18/99
18:00
18:00
11:40
8:45
8:40
8:35
1.5
0.0
0.0
1.9
2.3
3.3
4.5
2.5
0.5
7.5
5.2
6.4
0.057
0.036
0.081
0.077
0.140
0.101
11.6
23.2
23.2
554.4
372.0
388.4
5
2/18/99
8:58
2.7
17.1
0.124
1376.7
0
6
7
2/18/99
2/18/99
8:55
9:02
2.0
1.0
12.3
4.0
0.131
0.155
994.0
91.6
0.5
2.5
9
2/18/99
9:21
1.5
10.9
0.098
1492.5
0
9A
10
2/18/99
2/18/99
9:40
9:50
1.0
1.0
4.1
5.4
0.099
0.048
252.9
649.6
0
0
11
2/18/99
10:05
0.9
7.4
0.093
713.9
2
13
19
20
21
22
23
24
25
26
30
31
34
35
36
36A
37
2
3
3A
3*4
5
6
Hill's Pond Inlet*
Hill's Pond Spring*
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
2/18/99
10:12
10:25
10:20
10:35
10:45
10:52
11:00
11:05
11:10
11:15
11:15
11:20
11:18
11:30
11:30
11:37
11:50
11:55
12:00
12:05
11:55
11:50
0.6
0.0
0.6
0.2
0.4
0.1
0.3
0.1
0.0
0.5
0.0
2.7
0.2
0.0
0.1
0.1
0.2
0.1
2.2
0.0
0.1
0.1
0.3
0.0
5.5
1.9
4.2
2.6
3.0
2.3
2.2
2.4
1.3
1.4
0.1
4.8
3.6
0.3
1.6
0.7
1.8
0.3
1.0
0.0
1.2
1.0
0.051
0.045
0.111
0.090
0.104
0.087
0.094
0.153
0.128
0.065
0.088
0.000
0.042
0.043
0.087
0.079
0.069
0.037
0.071
0.051
0.101
0.102
0.086
0.061
391.8
177.9
298.8
109.3
247.4
205.1
106.3
141.0
35.5
47.8
11.9
9.4
47.1
24.6
55.1
18.5
61.0
12.5
53.5
5.6
41.6
38.5
1
1
1.5
0.5
2
3
2.5
2.5
1.5
1.5
0
0
0
0
0.5
0
2
0.5
2
0
0
0
523.7
0
24.6
0
2/18/99
7.1
7.3
* Collected while it was not raining
Note: Although two significant digits are shown for all arsenic concentrations, the GF-AAS
is only accurate to 2 ppb
46
Stormdraln Sampling Locations
Arsenic
Concentrations (ppb)
Stormdrain Network
Bathymetric Contours
/
Shoreline
1 - 3 Meters
below mean surface
4 - 5 Meters
below mean surface
4S
4
6 - 8 Meters
below mean surface
9 - 11 Meters
below mean surface
-4
vi
Stormwater Sampling
2/18/99
Arsenic Results
Figure 3-10
Orthophotography Source: MassGIS
Drainage Network Source: Arlington Department of Public Works record drawings
Nitrate 2/18/99
3.5
3.0
34
3
2.5
E
2.0C.
26
6
9
)1.5~
10
1
1.0
7
1130
0.5
213 2
35
3
37
0.0
1
-0.5
Drain No.
Figure 3-11
Stormwater Sampling
2/18/99
Nitrate, Sulfate, and Chloride Results
48
Figure 3-12: Stormwater Sampling 2/18/99
Phosphate Results
0.180
0.160 7
0.140 -
25
3
6
26
5
0.120 -
20
2--'
6
0
9
22
2
a. 0.100
9A
24
11
3A
1
21
21
-1a
0.080
3A
0.
23
0
0.060
a-
13
2
3*4
30
19
0.040
35
10
1
0.020 -
0.000*
Drain Outfall No.
34
Table 3-5
Stormwater Sampling Results 2/18/99
Drain 4 Sequenced Results
Time
Nitrate
Sulfate
(min)
(ppm)
1.5
2.7
2.7
3.1
4.3
2.1
2.0
2.0
1.8
2.2
1.9
1.0
0.6
0.3
(ppm)
4.5
7.1
8.0
20.6
27.9
16.2
15.2
16.5
15.5
15.0
11.7
6.0
3.6
1.2
o
0
0.3
5
10
15
20
25
30
45
60
90
120
240
Phosphate
(m
P04-P/L)
0.057
0.048
0.054
0.125
0.081
0.100
0.246
091697.8
0.100
0.129
0.144
0.125
0.068
0.079
Chloride
Arsenic
(ppm)
41.6
482.7
604.2
1951.1
5354.2
1486.3
1449.3
(ppb)
0.5
0
0
0
0
0
0
0
0
0
0
0
0
0
1612.9
1314.6
953.4
471.8
228.5
60.2
Note: Although two significant digits are shown for all arsenic concentrations, the GF-AAS
is only accurate to 2 ppb
50
Drain 4: 2/18/99
0.3
0.25
3 02
CUD'
- 00.15 -o 0)a
E 0.1
E.
0.05
0
200
150
100
50
0
Time (min)
-+-
Drain 4: 2/18/99
N03- (ppm)
--- S04 2- (ppm)
30
25
20
E 15
a.
10
5
0
200
150
100
50
0
Time (min)
Drain 4: 2/18/99
6000
5000 -
EA
4000
0.
0.
.
3000
. 2000
-
1000
0
*
0
50
100
200
150
250
300
Time (min)
Figure 3-13
Drain 4
2/18/99
Phosphate, Nitrate, Sulfate and Chloride Results
51
statistically significant from zero. Sampling performed on February 18, 1999 at Drain 4
appears to have captured two flushes of nutrients with no change in arsenic
concentrations (see Table 3-5 and Figure 3-13).
The grab sampling revealed several "hot spots" along the North Basin which showed
sporadically elevated arsenic concentrations over the period of sampling. The first area
of elevated arsenic concentrations is along the south cove of the North Basin, including
Drains 3 through 8. The second area of interest is along the northwest shore, near
Elizabeth Island. These areas had maximum arsenic concentrations of 10 ppb and 5 ppb,
respectively. Drain 20 (Route 2) and drains 36 and 36A (Massachusetts Avenue),
however, which account for the majority (59%) of the total stormwater inflow into Spy
Pond, recorded low levels of arsenic.
Two samples were collected from Menotomy Rocks Park on February 19, 1999 to
compare to Spy Pond stormwater samples. One sample was collected from the drain
outfall at Hill's Pond, prior to the mitigation wetland. The other sample was collected
from a spring in the park that flows into drain 20. Analysis of both samples revealed no
arsenic.
Chloride was measured on several dates after roads were salted to determine the effect of
road salt on Spy Pond arsenic loading. Very high levels of chloride were recorded at
several drains, however, high chloride levels did not correspond to high arsenic levels.
Direct analysis of road salt samples collected from the storage facility for this portion of
Route 2 also revealed undetectable levels of arsenic.
3.3.2 Catch Basin Sampling Results
Catch basin sampling results are included in Table 3-6. Sample locations are shown in
Figure 3-2. The results indicate that the catch basin sediments mainly consist of sand and
are low in arsenic. On the other hand, relatively large amounts of iron are present in the
catch basin samples. Since arsenic is readily sorbed by iron oxides, the small amounts of
52
arsenic found in the catch basin samples may be associated with iron precipitates. The
elevated lead concentrations in samples 75, 78, and 81 warrant further investigation.
Table 3-6
Selected Catch Basin Sampling Results
Sample
Silicon
Phosphorus
Chlorine
Iron
Lead
Arsenic
Number
%
%
%
%
ppm
ppm
75
32.00
0.0477
0.01176
1.135
290.2
<3.1
78
31.07
0.0876
<0.0037
1.083
568.0
<4.3
79
32.71
0.02146
<0.0040
1.516
54.33
3.4
80
34.96
<0.0019
<0.0037
1.332
32.5
1.7
81
26.89
0.3096
<0.0033
3.012
314.9
8.6
82
33.85
0.02871
<0.0041
1.506
68.7
1.8
84
34.72
0.00963
<0.0041
0.9723
46.8
2.3
85
32.81
0.0407
<0.0039
1.056
75.9
2.8
86
29.90
0.0851
0.00399
1.364
92.4
<1.8
87
33.73
0.02406
<0.0039
0.9104
39.9
2.3
88
32.29
0.02396
0.0542
1.296
66.8
2.4
3.3.3 Sediment Sampling Results
Results of our intensive sediment sampling program are included in Tables 3-7 and 3-8 as
well as Figures 3-14 and 3-15. The results from the first sampling round (samples 1
through 40) show large concentrations of arsenic are found in surface sediments
throughout Spy Pond. However, the North Basin has maximum concentrations almost 3
times as high as sediments in the South Basin.
As one would expect, in general higher concentrations are found in deeper portions of
Spy Pond due to sediment focussing However, comparing the concentration contours for
the North Basin in Figure 3-14 to the bathymetry in Figure 1-2, one notices the highest
53
Arsenic Sediment Sample Contoum
F
40-"
inteval: 300 ppmn
Acontour
A
A
300 -600
601-900
901 - 1200
4111
-1500
41201
*A
3
1501-2400
S A/
18
Location
A ASample
4
38
Pond Boundary
seiment
A9
33 A
A
29
A
-
S34
Arsenic Contours
Surface Sediment
Samples
Figure 3-14
Orthophotography Source: MassGIS
Arsenic Samples Contoured using ArcView Spatial Analyst with a 4-meter grid and 300 ppm contour interval
Table 3-7
Sediment Sampling Results
Samples Collected 12/11/98 by Gawel and Lukacs
Data
Depth of Water
Arsenic
Lead
Phosphorus
Sulfur
Chlorine
Chromium
Points
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
(m)
2.5
1.9
3.1
1.8
4.0
7.0
9.8
3.7
3.8
7.9
10.2
7.5
4.2
1.2
2.0
6.8
2.8
2.5
2.7
1.9
4.9
3.2
0.9
5.5
4.0
2.2
5.7
6.1
1.7
1.0
5.0
5.5
5.8
4.8
1.0
2.1
2.2
2.0
1.5
5.3
(ppm)
146.3
221.2
826.8
87.5
1570.0
1858.0
2043.0
1720.0
1480.0
1736.0
1737.0
815.6
738.7
1577.0
2644.0
1415.0
696.6
274.7
252.4
617.6
605.9
870.1
594.6
1074.0
971.9
154.1
845.0
853.2
568.1
153.8
510.4
656.0
815.8
813.1
118.3
261.6
152.7
159.2
202.2
363.7
(ppm)
1347
1312
1713
483.9
1877
1901
2486
2164
2106
2395
2416
2232
1956
1977
2011
2395
1632
1124
1138
1844
1839
1836
1917
2032
2232
1063
2156
1899
1276
1353
1411
2104
1958
1745
610.3
932.3
500.2
856.6
555.5
1243
%
0.2346
0.2572
0.2649
0.1139
0.2745
0.3155
0.3036
0.2768
0.2663
0.3014
0.2725
0.3304
0.268
0.2665
0.2632
0.2832
0.3106
0.2184
0.206
0.2105
0.1872
0.2167
0.2155
0.2256
0.2285
0.2078
0.2449
0.25
0.2219
0.2049
0.2081
0.2311
0.2537
0.2411
0.287
0.2502
0.1619
0.0816
0.1613
0.3031
%
1.448
1.597
2.132
1.55
2.431
2.524
2.349
2.122
2.293
2.394
2.251
2.5
2.487
2.304
2.033
2.18
2.068
1.574
1.92
1.578
1.687
1.54
1.521
1.479
1.441
1.647
1.293
1.43
1.485
1.405
1.437
1.526
1.413
1.319
1.062
1.374
0.7244
1.196
0.8794
2.349
%
0.0763
0.1338
0.0841
0.3133
0.1288
0.1016
0.0987
0.0812
0.1194
0.1097
0.1203
0.1456
0.1942
0.1352
0.1128
0.1581
0.0848
0.0733
0.1609
0.1399
0.0682
0.1072
0.1521
0.1211
0.1271
0.1315
0.1192
0.3558
0.1662
0.0528
0.0936
0.2986
0.3622
0.0999
0.4941
0.9064
0.0677
0.1995
0.0995
0.00827
%
0.0153
0.00805
0.00586
0.00285
0.00826
0.00547
0.0051
0.00485
0.00598
0.00742
0.00454
0.00537
0.0024
0.00584
0.00765
0.00473
0.028
0.01021
0.0137
0.00553
0.00307
0.00409
0.00646
0.00595
0.00474
0.00457
0.0051
0.00491
0.00344
0.0166
0.00371
0.00645
0.00673
0.0052
0.00933
0.01031
0.0313
0.00283
0.00255
0.0039
Iron
% 3.168
3.339
3.761
2.167
4.139
4.581
4.502
4.284
4.228
4.645
4.423
4.584
4.305
3.897
4.163
4.223
3.740
3.107
3.398
3.752
3.643
3.772
3.794
3.952
3.948
3.383
4.000
4.242
3.584
3.469
3.619
4.087
4.242
3.794
3.636
4.506
3.393
2.498
3.472
4.595
Copper
Zinc
i(ppm)
(ppm)
643.7
606.1
809.1
408.0
927.2
888.5
968.4
890.1
882.0
1047.0
1010.0
971.5
918.8
930.2
882.1
935.6
733.4
569.7
606.5
782.0
768.9
753.5
804.3
763.3
766.6
712.0
811.2
807.7
621.9
682.3
600.9
799.0
780.7
752.2
677.3
742.2
270.4
331.6
266.7
774.4
643.7
300.7
450.7
149.4
634.5
520.5
425.5
407.4
415.5
466.2
484.7
355.8
350.9
503.1
502.1
502.6
432.8
327.3
426.3
437.5
428.4
427.5
398.3
426.2
416.7
244.4
408.9
339.9
343.6
248.0
352.5
330.7
323.0
363.9
270.2
304.6
100.8
113.8
115.9
929.4
Table 3-8
North Basin Sediment Sampling Results
Samples Collected 2/19/99 by Gawel, Lukacs, MacLaughlin and Senn
Data
Points
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
64
65
66
67
68
69
70
71
72
73
74
76
Depth of Water
(m)
0.75
0.9
0.75
0.75
0.7
1
0.6
0.9
0.9
0.9
0.9
1.05
1.2
1.35
1.35
1.35
1.2
0.9
1.35
1.35
1.2
5
7
9
9
7
5
6
5
1.2
Arsenic
(ppm)
8.7
278.5
14.2
19.7
8.6
33.2
3.5
11.5
8.8
1.9
3.4
11.9
8.7
3.0
1.6
0.7
12.3
3.6
65.9
250.8
6.0
310.5
973.4
2314.0
2246.0
819.0
1212.0
522.1
960.2
3.6
Lead
(ppm)
30.1
214.9
60.9
102.6
37.1
227.2
144.9
98.5
138.9
45.7
33.8
86.1
66.5
65.9
59.3
41.2
46.9
64.0
198.5
619.1
217.3
1106.0
2543.0
2453.0
2374.0
2651.0
2216.0
1999.0
1837.0
142.6
Phosphorus
%
0.03013
0.1012
0.02693
0.0437
0.0506
0.1232
0.0698
0.0471
0.02187
0.02136
0.0437
0.0495
0.0339
0.0566
0.0304
0.02677
0.0543
0.0506
0.0665
0.1144
0.02225
0.255
0.273
0.3138
0.2979
0.3066
0.3021
0.2902
0.3015
0.02011
Sulfur
%
0.04603
0.5886
0.2171
0.3638
0.07495
0.9651
0.194
0.0958
0.2267
0.2021
0.1786
0.3194
0.1447
0.08434
0.07305
0.05829
0.1273
0.1067
0.6013
0.7128
0.06217
2.246
2.491
2.456
2.463
2.217
2.286
2.318
2.163
0.04056
Chlorine
%
0.0045
<0.0038
<0.0046
<0.0039
<0.0047
0.0995
0.01492
<0.0042
<0.0042
<0.0043
<0.0043
<0.0036
<0.0042
<0.0042
0.00844
<0.0042
<0.0039
<0.0044
0.0612
0.01933
<0.0044
0.2148
0.0946
0.0992
0.1562
0.184
0.1648
0.1191
0.096
<0.0044
Chromium
%
0.01318
0.00256
0.00207
0.0287
0.00176
0.00359
0.0576
0.00456
0.00188
0.01717
0.01012
0.01714
0.0377
0.0729
0.0366
0.00687
0.0789
0.0355
0.01628
0.0324
0.077
0.01055
0.0056
0.00639
0.00438
0.0058
0.00494
0.0066
0.00531
0.1262
Iron
%
1.702
3.448
1.304
1.282
1.938
1.601
1.646
1.898
1.252
1.267
1.285
1.576
1.390
1.913
1.637
1.276
2.170
2.139
1.730
2.449
1.867
3.889
4.514
4.539
4.599
4.390
4.375
3.985
3.847
1.788
Copper
(ppm)
<1.3
29.9
9.9
15.6
<1.3
50.3
23.8
13.1
9.3
<1.3
<1.3
18.7
2.6
3.0
16.0
3.6
4.9
1.4
55.0
73.2
9.9
297.7
394.3
480.1
522.0
416.3
445.2
369.8
413.8
4.4
Zinc
(ppm)
53.7
134
78.6
90.5
52
277.2
166.9
74.7
48.4
28.8
20.1
116.2
58.2
48.4
39.9
24.1
52.5
47.8
193
281.8
59.6
560.5
974.6
1038
1044
1006
945.6
914.7
885.7
52.8
Sediment Core Sample
Concentration Bars
[
Arsenic (0.7 to 2,644)
Lead (30.1 to 2,395)
Concentration in ppm
Stormdrain Network
Arsenic vs. Lead
Surface Sediment
Samples
12/11/98 and 2/19/99
Figure 3-15
Orthophotogrpahy Source: MassGIS
Drainage Network Source: Arlington Department of Public Works record drawings
arsenic concentrations do not correspond to the deepest section of the Pond. An area of
high arsenic concentrations appears in Figure 3-14 near the south shore of the North
Basin which is inconsistent with what would be expected from standard sediment
focussing. The second round of sampling (samples 41-76) concentrated on further
defining the North Basin hot spot. High concentrations of arsenic were found close to the
shore in the area of the hot spot (Sample 45, 278.5 ppm). Extensive near-shore surface
sediment sampling in the North Basin area did not reveal any other area near shore where
arsenic concentrations were as elevated.
Figure 3-15 compares arsenic concentrations to lead concentrations in the surface
sediments. A possible significant source of arsenic to Spy Pond is through the historical
use of lead arsenate as a pesticide (see Section 4.3). A comparison of the two elements
does not reveal any apparent correlation however, lead concentrations may be skewed by
its use for other purposes (including leaded gasoline).
3.4 Geographic Information Systems (GIS)
3.4.1 GIS Software
The author established an understanding of the site and the sampling results using ESRI's
Arcview 3.1 and ARC/INFO in conjunction with digital topography, land use, and
orthophotography data developed by MassGIS, a Division of the Massachusetts
Executive Office of Environmental Affairs.
3.4.2 Data Sources
To accurately capture the many layers of geographic data in a consistent format, the
author digitized all new data against the NAD83 Massachusetts State Plane Coordinate
System. MassGIS is a valuable resource that is consistently maintained and updated. To
ensure easy integration with future data supplied by MassGIS, the author converted all
digitized data layers to the Metric System.
58
The author digitized the majority of layers using ESRI's ARC/INFO and CalComp 9100
48-inch digitizing tablet. Paper maps were registered to common features on the existing
data, ensuring a maximum root mean square (RMS) error of 0.02. Typically, one aims at
a lower RMS to improve absolute accuracy; however, given the nature of the project and
the quality of the source documents, the RMS was appropriate [Thomas, 1999].
All digitizing was performed based on the State Plane Coordinate System. The
watershed boundary delineation was created by the Metropolitan Area Planning Council
and adjusted according to topography and the existing stormwater drainage system. The
author digitized the stormwater drainage system using current Arlington Department of
Public Works (DPW) records. The drainage system was digitized from the paper map
such that the GIS data has an understanding of the direction of flow of the system. This
data layer could be used for future modeling and further understanding of the existing
stormwater loading on the Pond.
The author digitized the bathymetry data layer using data from the Massachusetts
Division of Fisheries and Wildlife. However, the paper data source was developed prior
to the filling of 2 hectares of the Pond for the expansion of Route 2. Therefore, the
author adjusted the depth breaklines to reflect approximate current conditions on the
southwest shore of the South Basin. The adjustment of the Pond edge boundary was
made using MassGIS orthophotography (1-m resolution). The historical mapping was
digitized based on Sanborn Map & Publishing Company, Limited Fire Insurance Maps.
Data sources for digitizing are summarized below in Table 3-9.
59
Table 3-9
GIS Data Sources
Base Layers
DataLayers
Source
United State Geological
Survey (USGS) Topography
Quadrangle Maps
Orthophotographs
Land Use
Hydrography
Hypsography
Digitized Layers
Massachusetts Executive Office of Environmental
Affairs MassGIS (MassGIS)
Data Layers
Source
Stormwater Drainage System
Watershed Delineation
Bathymetry
Historical Information
Arlington Department of Public Works record drawings
Metropolitan Area Planning Council GIS
Massachusetts Division of Fisheries and Wildlife
Sanborn Map & Publishing Company, Limited. Fire
Insurance Maps
MassGIS
MassGIS
MassGIS
MassGIS
Raw Analytical Data Layers
Data Layers
Source
Surface Sediment Samples
Locations
Stormwater Samples Locations
Trimble Global Positioning System Unit with
Differential (GPS)
Arlington Department of Public Works record drawings
and GPS
Logbooks (1998) and MassGIS orthophotography data
layer
Logbooks (1998) and Arlington Department of Public
Works record drawings
Water Column Sample
Locations
Catch Basin Sample Locations
Derived Layers
Data Layers
Source
Surface Sediment Sample
Concentration Contouring
Spy Pond Profile
Arcview 3.1 Spatial Analyst
Arcview 3.1 3-D Analyst
60
3.4.3 Raw Analytical Data Layers
MacLaughlin, et al recorded all sediment sample locations in geographic coordinates
(longitude and latitude in degree/decimal minutes) using a Trimble global positioning
system receiver with a differential (GPS). Furthermore, coordinate locations were
recorded approximately every 6 meters along Spy Pond's shoreline to establish the
accuracy of the GPS. For a final check on accuracy, the data points collected by Trimble
receiver were compared to data collected by a Garmin GPS receiver. The author
transformed the geographic coordinates into NAD83 Massachusetts mainland state plane
meters by calculating negative decimal degrees from the degree decimal minutes in MS
Excel and then projecting the decimal degrees to state plane meters using Arcview 3.1
coordinate projection algorithms. For positional accuracy confirmation, the author
viewed the transformed points in conjunction with MassGIS digital USGS topography
and orthophotography data layers.
The author established stormwater sample locations using a combination of GPS points,
Arlington DPW record drawings and information recorded in the field logbook. To
create the catch basin sampling location data layer, the author used locations recorded in
the field logbook and Arlington DPW record drawings.
3.4.4 Derived DataLayers
The author used Arcview 3.1's Spatial Analyst extension tool for surface and volumetric
calculations. The tool extrapolated the bathymetry data layer to create the basins of the
pond in three dimensions. Spatial Analyst split the Pond into various shapes and
fractions to determine volumes and surface areas for preliminary mass balance
calculations.
Furthermore, the author used Spatial Analyst to analyze the raw surface sediment data by
establishing preliminary arsenic concentration contours throughout Spy Pond. Spatial
Analyst produces contours from a set of data points by processing the analytical results
61
through a triangular irregular network (TIN). The number of sediment samples was
insufficient for Spatial Analyst to provide completely accurate contouring, however, the
contours provide a preliminary suggestion of concentrations throughout the Pond
[Thomas, 1999].
The author used ArcView 3.1's 3-D Analyst extension tool to visualize the data in three
dimensions. To generate profiles of Spy Pond, the author employed 3-D Analyst to
interpret the bathymetry data layer in three dimensions. Once the data layer is interpreted
in three dimensions, a profile can be produced from any direction along the Pond.
3.5 Conclusions
The comprehensive sampling and data analysis discussed in this chapter have resulted in
the formation of several initial hypotheses concerning the character of arsenic
contamination in Spy Pond. A prognosis of the effect of stormwater runoff and road salt
loadings on the Pond uncovers a minimal arsenic impact delivered through the 43 drain
outfalls. A comparison of chloride and arsenic in sediments and stormwater reveals no
correlation, suggesting road salt is not a significant source of arsenic. Finally, a first
attempt at an arsenic mass balance in Spy Pond, as discussed below, discloses a large
unidentified input of arsenic, probably entering the Pond via groundwater.
3.5.1 Arsenic Loading to Spy Pondfrom StormwaterRunoff
Table 3-10 summarizes preliminary stormwater runoff arsenic loading calculations. The
calculations use the equation:
Q = CIA
Where:
Q = peak rate of runoff in
m 3/y
I = rainfall intensity in rn/yr
A = Drainage area in m2
C = Runoff Coefficient
62
Figure 3-16
Spy Pond Stormwater Runoff Loading Calculations
Subbasins
Est.
Est.
Arsenic
Arsenic
Arsenic Load
Flow, Q
Conc.
Load
over 30 yrs
mA3/yr
10A-6g/L
g/yr
kg
Percent of
Watershed
Storm Drain Outfalls
Average
Area
mA2
Drainage Area Storm Intensity
C
m/yr
%
# 21, 22, 23
2
213,481
7
1.09
0.65
151,251
1.75
265
8
# 24
3
133,582
4
1.09
0.65
94,643
3.00
284
9
# 25 -35A
4
163,607
5
1.09
0.65
115,916
1.40
162
5
# 36, 36A, 37
5
194,829
7
1.09
0.9
191,127
1.08
207
6
# 9A, 10
6
163,658
5
1.09
0.65
115,952
0.63
72
2
# 20, 20A
7
1,570,760
52
1.09
0.65
1,112,883
1.50
1669
50
# 11
8
115,102
4
1.09
0.65
81,550
1.75
143
4
# 7, 8, 9
9
45,584
2
1.09
0.65
32,296
2.00
65
2
# 1, 2, 3, 3A, 4, 5, 6
10
315,638
11
1.09
0.65
223,630
3.83
857
26
# 19
11
23,237
1
1.09
0.65
16,463
1.25
21
1
# 12, 13, 14,15, 16, 17, 18
12
55,430
2
1.09
0.65
39,272
0.50
20
1
Total Drainage Area
2,994,908
100
1.09
0.65
2,121,892
1.70
3606
108
annual precipatation = 43 in/year = 1.09 m/yr [Logan Internation Airport Data]
C = Runoff Coefficient [Robertson, 1988]
See Figure 1-4 for Storm Drain Outfall Location
See Figure 1-5 For Watershed Subbasins
An average annual rainfall of 1.09 mlyr based on Logan International Airport data was
used. The runoff coefficient was estimated at 0.65 for the entire urban residential
watershed. The area of each basin was determined using Areview 3.1.
Arsenic concentrations recorded for each drain outfall were averaged and applied to an
overall average for the drainage basin. The calculations indicate less than 4 kg of arsenic
enter the pond annually via the storm drainage system. If this result is extrapolated over
30 years, the total input from the storm drains from 1969 to 1999 is approximately 108
kg. If the highest concentration of arsenic measured in the stormwater runoff, 10 ppb, is
applied to the entire watershed and expanded over 30 years, the stormwater system
contributes an absolute maximum of 630 kg total.
3.5.2 Road Salt Runoff as a PotentialSource
Road salt was initially considered a viable potential source of arsenic to the Pond based
on the high concentrations measured in the South Basin sediment samples and the
sediment core results of Ivushkina (1999). Stormwater samples were collected on two
occasions after salt had been placed on the roads. Figure 3-16 shows the relationship
between arsenic and chloride concentrations. Arsenic and road salt applications do not
appear to be correlated.
3.5.3 PreliminaryQuantificationof Arsenic in Spy Pond
The total amount of arsenic in Spy Pond sediments can be estimated using the surface
sediment data collected on December 12, 1998 and the surface area of the sediments
calculated using ArcView Spatial Analyst. Based on sampling results, arsenic
concentrations of 500 ppm to 800 ppm were used to calculate the total arsenic load in the
top 15 cm of pond sediments. The results of these calculations place the total amount of
arsenic in the top 15 cm of Spy Pond sediments between 1,200 kg and 1,920 kg.
64
Figure 3- 16: Arsenic as a Function of Chloride
12
10
.0
0.
.
8
6
* As
-4-
4
- - -- - -
- - +
- - *- - --
-
2
-+
0
1
10
100
Chloride (ppm)
1000
10000
3.5.4 Mass Balance Calculations
Figure 3-17 summarizes a preliminary mass balance of arsenic fluxes in Spy Pond using
the stormwater, sediment, and water column data along with areas and volumes found
using Arcview Spatial Analyst. Our estimate of the amount of arsenic entering the Pond
annually via stormwater runoff (as described in Section 3.5.1) is less than 4 kg/yr, with an
absolute maximum of 21 kg/yr. Shanahan's (1997) estimate of the Pond's turnover, 0.8
volume/year, and the concentration of arsenic in the surface waters during the summer
(-100 nM) were used to calculate the amount leaving the Pond annually, approximately
17 kg/yr. Finally, the arsenic flux from the water to the sediments was calculated using
an estimated 0.5 cm/yr sediment deposition rate (see Section 2.1) and a total arsenic load
for the top 15 cm of sediments of 1,200 kg to 1,920 kg (see Section 3.5.3). Using these
estimates the arsenic flux to the sediments is between 40 kg/yr and 64 kg/yr. Therefore,
according to the mass balance, 36 to 77 kg /yr is entering the Pond from sources other
than the stormwater system. The most likely culprit is groundwater entering the Pond
which led to an investigation of possible historical arsenic sources to Spy Pond.
66
4-21 k
me
17 kg/yr
/36
- 77 kg/yr?
40 - 64 kg/yr
Figure 3-17 Arsenic in Spy Pond
4. Historical Investigation
4.1 Introduction
The preliminary mass balance indicates that stormwater runoff is not the primary input of
arsenic to Spy Pond. A potential significant source may be an arsenic groundwater
plume, originating from previous land use, migrating to the Pond. Therefore, historical
land use and maintenance of the Pond was extensively researched in an attempt to explain
the presence and quantity of arsenic in the pond. Resources explored include:
" Arlington Public Library, including Arlington Advocate archives
e
Arlington Town Planning Office
e
Boston Public Library
e
Massachusetts Highway Department Library
e
Massachusetts State House Special Collections Library
* Arlington Historical Society
e
Arlington Spy Pond Committee
*
Residents of Spy Pond.
All available previous reports on Spy Pond were researched, as well as historical books
and maps of Arlington to understand development around and use of the Pond. Pictures
and anecdotal information were acquired from the Arlington Historical Society.
Arlington Advocate articles on market gardening and gypsy moth infestation were
reviewed to glean any information about arsenical pesticide use.
Information from the Sanborn Maps and Publishing Company, Limited, Fire Insurance
maps (Sanborn Maps) dating from 1885 to 1971 were digitized using Arcview 3.1 (see
Section 3.4) to create convenient maps displaying the changes around Spy Pond over a
period of almost 100 years. These maps show how Spy Pond's watershed changes from a
commercial and agricultural center to an almost purely residential area.
68
4.2 Methods and Discussion
4.2.1 Sanborn Fire InsuranceMaps of Spy Pond
An in depth investigation of the industry and use of the land surrounding Spy Pond was
conducted using Sanborn Maps and available historical literature. Arlington has a long
history of industry and mills. At its peak, Mill Brook had seven major mill ponds. The
watershed of Spy Pond has a somewhat less industrious history. Market gardens and ice
houses cropped up along its shores at the turn of the century. However, since the 1950s,
the vast majority of the watershed of Spy Pond has been residential (see Figures 4-1
through 4-5).
Figure 4-1 shows industry first appearing around Spy Pond in the late 1800s. By the
1900s, several ice houses began to appear to store and ship ice harvested from the pond.
In conjunction with the ice harvesting business, an ice tool manufacturing company
existed adjacent to the Pond. Several small businesses appeared along Massachusetts
Avenue, near the north end of the Pond including: a garage and blacksmith, a painting
shop, a barber, an upholsterer, a printing shop, and a large greenhouse farm. To the north
of the Pond, just out of the present-day drainage basin, a large lumber yard, a coal, wood
and hay distributor and an insecticide manufacturer existed along the railroad tracks (now
the Minute Man Bicycle Path).
The next decade, the 1910s, saw the ice tool manufacturing business being replaced by a
building materials shop, a greenhouse/market farm appearing along the east shores of Spy
Pond, and a livery opening on Massachusetts Avenue (see Figure 4-2).
Figure 4-3 describes the 1920s, which enjoyed the largest expansion of businesses along
Spy Pond. One truly understands how central the Pond was to the lives of those living
near it. Market gardens explode around Spy Pond in this decade. Several more ice
houses appear along the south shore and a foundry is shown along the southern shore of
69
Spy Pond - 1900s
Sc
AJw-
r
fIJA~
7.0
0-
Spy Pond Industry 1900s
boat house
coal pit
farm/green houses
garage
ice house
insecticide mfg.
Little
V
-ook
C-16
shops
1 Wood &Co. Ice Tool Mfg.
2 New England Ice CoJArl.&Belmont Ice
3 New England Ice CoJAr.&Belmont Ice
4 Cambridge Ice Co/Gage Ice Co.
5
tool manufacturing
lumber yard
",SpyPond Watershed
41 I I
Data Sources:
Spy Pond Industry History digitized from Sanbom Map & Publishing Company., Limited
Fire Insurance Maps
Spy Pond Watershed boundaries adjusted from Metropolitan Area Planning Council
stormwater basin GIS data
6
Richard's Coal, Wood, Hay
Frost Insecticide Co.
7
Blanchard Kendall & Co. Lumber Yard
8
Rawson's Green Houses
9 Wood & Co. Ice Tool Mfg.
10 Menotomy Boat House
11 Wood & Co. Ice Tool Mfg. hot house
12 various shops
13
Garage, Blacksmith, Painting Shop
14
Garage & Repair Shop
hamess, barber, upholestry, printing
15
Figure 4-1
a t
Spy Pond - 1910s
r~
V
t,,
Spy Pond Industry 1910s
farm/green houses
tool manufacturing
lumber yard
3 livery
Spy Pond Industry 1900s
boat house
coal pit
farm/green houses
garage
ice house
insecticide mfg.
shops
tool manufacturing
lumber yard
Spy Pond Watershed
i
2 New England Ice GoJArl.&belmont Ice
3 New England Ice CoiArl.&Belmont Ice
L ittle
PO
Z
P,rAf
k
4 Cambridge Ice CoiGage Ice Co.
5 Richard's Coal, Wood, Hay
6 Frost Insecticide Co.
7 Blanchard Kendall & Co. Lumber Yard
8 Rawson's Green Houses
10 Menotomy Boat House
11 Wood & Co. Ice Tool Mfg. hot house
ilk
Data Sources:
Spy Pond Industry History digitized from Sanbom Map & Publishing Company., Limited
Fire Insurance Maps
Spy Pond Watershed boundaries adjusted from Metropolitan Area Planning Council
stormwater basin GIS data
12 various shops
13
Garage. Blacksmith, Painting Shop
14 Garage & Repair Shop
15 hamess, barber, upholestry, printing
16
Uvery
17
Arlington & Belmont Ice Co. (replaces 1)
18
Davis & Son Building Materials (replaces 9)
19
J. Lyons Green Houses
Figure 4-2
SpyPondIndustry
1920s
Icehouse
houses
shops
autorepairshop
foundary
ordIndustry1910s
farmfgreen houses
toolmanufacturing
lumberyard
Lfarmfgreen
if,
1ondIndustry19009
py 9
boathouse
coalpit
farm/green
houses
garage
Icehouse
Insecicide mfg.
/
shops
-J
tool manufacturing
lumberyard
SpyPondWatershed
2
3
4
5
6
I
-"Flvdan
' -
V
I
10 Menotomy Boat House
11 Wood &Co. e Tool M . hot house
I22
New England Ice CoiAzl.&Belmont Ice
New England Ice CoJAr.&Belmont eo.
Cambridge Ice CoiGage IceCo.
Richard's Coal, Wood, Hay
Frost Insecticide Co.
7 Blanchard Kendall & Co. Lumber Yard
nausea
~1 rsawson
0
rwwson aa '.,rean
Wrean riwuses
o
Data Sources:
Spy Pond Industry History digitized from Sanbom Map & Publishing
Company., Limited Fire Insurance Maps
Spy Pond Watershed boundaries adjusted from Metropolitan Area
Planning Council stormwater basin GIS data
15 hamess, barber, upholestry, printIng
|
Ii
II
16 | Livery
-1 I ~ninaron
& maimoni ice LO. ireoraces vi)
if
Anington a n
. ..
-.
r18 Is&
19
-
.
..
-
.
Son Building Materials (replaces 1)
J. Lyons Green Houses
a
20 Tires, upholstering (replaces 12)
21 Arlington Auto Co. Repair Shop (replaces 14)
Alington Auto Co. Repair Shop (replaces 13)
23 M.E. Moore Green Houses
24 Tappan Green Houses
25 Arlington Foundry Co.
26 1Wyman Bros. Farm
~.. I Lemunuuu ice ~,g.
t,8mon0GO see w.
4er
28 ICambriNdge Ice Co.
29 1Lyons Green Houses
30
Wyman Bros. Farm
31 George Hill Green Houses
Figure 4-3
at
Spy Pond - 1951
:j
c~
U3
IJ!
Spy Pond Industry 1951
Wshops
a33
"O
Data Sources:
321 Acme Window Conditioning Co.
Arlington Pipe &Supsoy Co.
34 Filling Station
Service
35&
Spy Pond Watershed
K'1 7 --
~urtd
0
36 Filling Station
37 Roofer
38 Arlington Center Motor Co.
Spy Pond Industry History digitized from Sanbom Map & Publishing
Company., Limited Fire Insurance Maps
Spy Pond Watershed boundaries adjusted from Metropolitan Area
Planning Council stormwater basin GIS data
Figure 4-4
16
Spy Pond - 1971
a
xl
-I
.lS
Spy Pond Industry 1971
dry cleaners
1968 condos
p Pond Industry 1951
shops
lumber yard
auto repair shop
gas station
Spy Pond Watershed
U2
I
32 Acme Window Conditioning Co.
33 Arlington Pipe &Supply Co.
34 Filling Station
35 iAuto
Sales & Service
rI
49
_ 41
Data Sources:
Spy Pond Industry History digitized from Sanbom Map & Publishing
Company., Limited Fire Insurance Maps
Spy Pond Watershed boundaries adjusted from Metropolitan Area
Planning Council stormwater basin GIS data
37
roorer
38 Arlington Center Motor Co.
39 Dry Cleaning & Pressing (replaces 36)
40 Condominiums
Figure 4-5
the north basin. The blacksmith shops along Massachusetts Avenue disappear and are
replaced by automobile tire and repair shops. The pesticide manufacturing, lumberyard,
and coal, wood, and hay distributor still exist to the north of the Pond.
The next Sanborn Map available is for 1951 (see Figure 4-4) and shows a dramatic
change in land use around the Pond. All of the industry and farming around Spy Pond
disappears and is replaced by residential housing. The exception is along Massachusetts
Avenue, where small businesses such as filling stations, a pipe supplier, a window
supplier, a roofer and automobile sales shops exist. The large businesses along the
railroad are no longer present. This is, for the most part, how Spy Pond looks today.
Condominiums are built along the east shore of the Pond in 1968, but otherwise no major
construction took place near the Pond after World War II (see Figure 4-5).
4.2.2 Present Day Uses
The entire watershed of Spy Pond is densely developed except for 11.9 hectares within
Menotomy Rocks Park [Chesebrough and Duerring, 1982]. The major land use in the
Spy Pond watershed is residential single family housing (see Figure 1-6). Apartment
houses and condominiums are found along portions of Pleasant Street, Massachusetts
Avenue, and adjacent to the pond. Massachusetts Avenue and portions of Pleasant Street
are also zoned for commercial use [MassGIS, 1998]. The entire area is serviced by the
Metropolitan Sewer District (MSD) with treatment provided by Deer Island and no
overflows or bypasses from the Arlington system are known to exist [Shanahan, 1997].
There is no current industrial water use within the Spy Pond watershed. The town
landfill, closed in 1969, is located downstream and outside of the watershed. No areas of
intense development or construction exist in the watershed, and all major farming ended
prior to 1950.
75
4.2.3 LiteratureReview
A review of literature regarding high arsenic concentrations in lake sediments was
conducted in an attempt to further comprehend the situation in Spy Pond. Three cases of
extremely high arsenic concentrations in sediments, each through different routes, are
presented.
Arsenic in sediments within the Aberjona River watershed has been heavily researched.
The source of arsenic contamination in this region has been traced to its industrial
history, including the manufacturing of arsenical pesticides. Another example, Lake
Rotoroa, New Zealand, has elevated levels of arsenic due to heavy applications of sodium
arsenate for weed control. Finally, Coeur d'Alene Lake, Idaho, has significant arsenic
contamination from mine tailings. This case is significant because data indicates an
upward movement of arsenic concentrations in the sediment, potenitally due to eutrophic
conditions within the lake.
Aberjona Watershed
The Aberjona River watershed encompasses an area of 65 km and contains a multitude of
hazardous waste. Soils and sediments at and near one site, the Industri-Plex Superfund
Site, have been found to contain extremely high concentrations, up to 30,800 mg/kg (dry
weight) of arsenic [USEPA, 1986]. The geology of the Aberjona River watershed, like
the Spy Pond watershed, does not suggest a significant geological source for elevated
levels of arsenic [USGS, 1944; Aurilio, 1992]. For the Aberjona River watershed,
historical investigations reveal industrial sources.
Arsenic contamination has moved from the Industri-Plex site to sediments in the
Aberjona River and the Upper and Lower Mystic Lakes, strongly implying that the river
is an important migration route for arsenic from the Industri-Plex sites to the lakes (see
Figure x). Arsenic peaks from several cores from the lakes range from over 500 to
almost 2,000 mg/kg (dry weight), and 30 to 450 mg/kg (dry weight) for the Upper and
76
Lower Mystic Lakes, respectively [Aurilio, 1992; Knox, 1991; Spliethoff, 1992]. In the
Halls Brook Storage Area, which receives runoff from the Industri-Plex site,
measurements of arsenic in sediments range from 35 mg/kg (dry weight) to as high as
9,830 mg/kg (dry weight) [Aurilio 1992; Roux Associates, 1991; Knox, 1991].
Historical records compared to the current distribution of arsenic concentrations in soils
and sediments suggest that arsenical wastes produced during chemical manufacturing at
the Industri-Plex site was the most important source. The processes of producing sulfuric
acid and arsenical insecticides, specifically lead arsenate, continued in high volumes from
the late 1800s to the 1930s [Aurilio, 1992]. The Aberjona Watershed may be significant
to Spy Pond for two reasons. One reason is because research points to insecticide
manufacturing as a significant arsenic source, and insecticide manufacturing took place
near Spy Pond. Secondly, Figure 1-7 describes the surficial soils surrounding Spy Pond.
A highly transmissive soil, glacial outwash, underlies Spy Pond along the line of
maximum sediment contamination. This may mean that the source is further from Spy
Pond than initially perceived. The glacial outwash valley that underlies Spy Pond
includes the contaminated Aberjona River and the Upper and Lower Mystic Lakes
upgradient of the Pond.
Lake Rotoroa, New Zealand
Lake Rotoroa in New Zealand (370 48'S, 175' 16'30"E) is a 54-hectare urban lake with a
138-hectare residential catchment area and no significant anthropogenic or natural arsenic
inputs. In 1959, 39 hectares (70% of the lake surface area) were treated with 11,000
liters of sodium arsenate in addition to a 0.5-hectare trial, supplying over 5,500 kg of
arsenic to the lake or about 100 kg/ha. The application targeted the shallow weedinfested areas of the lake (0-3.7 m) and no other sodium arsenate applications were made
to the lake. This application successfully killed plants until 1970 [Nriago, 1994].
Elevated levels of arsenic were noted in sediments (540-780 mg/kg) and additional
sediment and core samples were collected. A close relationship between arsenic
concentration and lake depth was evident, with the highest arsenic levels recorded in the
77
deepest part of the lake. The overall mean arsenic sediment concentration was 224
mg/kg. This suggests little of the original 5,500 kg of arsenic applied for aquatic weed
control was lost from the lake [Nriago, 1994].
Arsenic migration within sediment and interstitial waters has been reported by Aggett and
O'Brien (1985) in association with seasonal hypolimnetic deoxygenation (present in Spy
Pond). When compared to several lakes in the Wisconsin area, with similar cumulative
sodium arsenite application rates (kg/ha), Lake Rotoroa has a significantly higher
concentration in its sediments [Nriago, 1994]. Section 4.3.3 and Table 4-1 discuss the
sodium arsenite and arsenic oxide applications to Spy Pond. The total amount of arsenic
applied to Spy Pond for weed control purposes is estimated to be less than 1 kg, which is
much less than Lake Rotoroa and the Wisconsin Lakes. Even if the amount applied to
Spy Pond is underestimated by a factor of two, the total arsenic input from herbicides is
still much less than the amount of arsenic found in the Pond.
Coeur d'Alene Lake, Idaho
Sediments of Coeur d'Alene Lake, Idaho, are heavily contaminated with mine tailings
that contain, among other toxic elements, high levels of arsenic. Several authors have
raised a concern that eutrophication and the concomitant development of a seasonally
anoxic hypolimimion, the case in Spy Pond, could combine to significantly raise
concentrations of toxic trace elements, as well as soluble nitrogen and phosphorus. The
possibility that lake eutrophication and the development of a seasonally anoxic
hypolimnion could mobilize arsenic from the sediments into overlying waters led
Harrington, et al., to evaluate arsenic phase associations. Although Coeur d'Alene Lake
is not currently classified as a eutrophic lake, it did experience periods of anoxia in the
1970s [Harrington, et al., 1998].
The mean concentration of arsenic in the Coeur d'Alene Lake sediments is 201 mg/kg.
In examining sediment core samples (-0.5 m deep), enrichment of arsenic within 15 cm
of the sediment-water interface is evident in nearly every core examined. Arsenic was
found to correlate strongly with iron and manganese, but not lead and zinc, in the
78
sediment core profiles. In general, Harrington, et al. (1998), found the lake sediments to
be highly reduced, with most redox potentials consistently below zero mV. They
concluded that the maximal abundance of redox-active elements (including As, Fe, and
Mn) occurs near the sediment-water interface in the region of the redox boundary (2-6
cm). This pattern suggests diagenetic cycling of these elements by oxidation-reduction
reactions resulting in the migration of arsenic upward, into surface sediments
[Harrington, et al., 1998].
Such a hypothesis as developed for the Coeur d'Alene Lake case may explain the high
arsenic levels found in the upper sediments of Spy Pond if the source is found to be
historic rather than current (see Section 2.1). Further sediment core analyses need to be
performed for Spy Pond before any conclusions can be drawn.
4.3 Potential Arsenic Sources in Spy Pond
A combination of the sampling results, preliminary mass balance, historical mapping and
literature review revealed several potential sources of arsenic. The following describes
each source, its potential relevance, and whether further investigation is required.
4.3.1 Ice Harvesting
Ice harvesting was the most prevalent industrial use of Spy Pond. Starting at a small
scale in the early 1800s, the industry steadily grew to several large ice houses from the
1840s to the 1920s. Gage, Cambridge Ice Co., and others built ice storage houses and
later built a spur railroad track to connect to Charlestown. The ice business thrived until
the 1920s when a combination of warmer weather and fires at the storage houses
destroyed the business [Sanborn Maps & Publishing, Limited; Duffy, 1997; Arlington
Heritage Trust, 1977]. Although ice houses themselves do not appear to be a source of
arsenic, their success brought the railroad to Spy Pond, which may have transported
and/or used arsenical pesticides.
79
4.3.2 Market Gardening
In the 1870s, one of the chief industries in Arlington was market gardening. The north
and east shores of Spy Pond and many hectares along Pleasant Street were used
extensively for commercial vegetable gardens. By 1907, it is said that Arlington was the
number one market garden producer in the country. Apparently, the land adjacent to Spy
Pond was heavily fertilized because the original land was not suitable for farming
[Cortell, 1973]. In the seventeenth century most of the area south of Spy Pond was
wetland. The "Great Swamp" stretched along the banks of Menotomy River (Alewife
Brook) and south of the Pond. Over the generations, this area has been filled and
fertilized to turn it into usable land [Arlington Historical Society Map Collection].
From the late 1800s to mid-1900s, inorganic arsenicals were used extensively as
pesticides in agriculture [Nriago, 1994]. The local production of lead arsenate (see
Section 4.2) likely resulted in this being the pesticide of choice around Spy Pond. Frost
Insectide, a manufacturer and distributor of insecticides, was located near Spy Pond (see
Figures 4-1 through 4-3). Whether Frost Insecticide produced lead arsenate has not been
determined. However, the historical use and production of lead arsenate as a pesticide in
the vicinity of Spy Pond should be investigated further.
4.3.3 Treatment History of the Pond
1871 marks the first report of nuisance vegetation growing in Spy Pond. In 1880, Spy
Pond was declared unfit for domestic use due to the presence of a large amount of the
weed Clathrocytis [Cortell, 1973]. The 1920s saw several attempts to improve the
condition of the lake including raising its elevation, dredging, and copper sulfate
treatments to kill the weeds [Cortell, 1973].
Annual records from the Department of Public Health between 1932-1951 show that Spy
Pond was considered suitable for bathing. In 1951, it was confirmed that no sewerage
entered the pond and that the entire area surrounding the pond was sewered [Cortell,
80
1973]. The pond enjoyed a period of good health in the early 1950s, although note was
given to a 2-acre truck farm in the northeast cove that likely used fertilizers. By 1956,
the pond was in need of weed control again and 0.55 ppm of copper sulfate was applied
in the summers of 1956 and 1957 [Cortell, 1973].
In 1960, the Massachusetts Department of Public Health hired the Northeast Weed and
Brush Control Corporation of Worcester to do a 5-year weed control project [Cortell,
1973]. A summary of treatments follows in Table 4-1 [Cortell, 1973]. The author made
an attempt to quantify the amount of arsenic that entered Spy Pond through weed control
(see Section 3.5). Using the highest application of sodium arsenate recorded (-5,000
gallons) and applying this amount to applications where the amount was not determined,
the total amount of arsenic applied to the lake is less than 1 kg.
In the summer of 1963, it was very evident that the fish population was undergoing a
severe decrease. Three or four out of every 100 yellow perch had one or two eyes in
various stages of deformity and in some cases empty eye sockets were present. At the
time, sodium arsenate was believed to be the cause, and the Massachusetts Department of
Fish and Game recommended that it no longer be used to treat the pond [Cortell, 1973].
Up to 1970, the Commonwealth of Massachusetts had expended approximately $25,000
on vegetation control of Spy Pond. In 1970 a total of $500 to $750 was appropriated for
the next 3 years of weed control [Cortell, 1973]. This implies that measures to control
the weed population in the Pond were extremely limited between 1970 and 1973. Further
weed control application information was not determined.
Unless an extraordinarily large weed control application (much larger than any recorded)
occurred, the application of sodium arsenate and arsenic oxide to control weeds is not a
major source of arsenic contamination in Spy Pond.
81
Table 4-1
Summary of Weed Control in Spy Pond
[Cortell, 1973]
Date
1921
8/1956
9/1956
Chemical
Applied
Copper Sulfate
Copper Sulfate
Copper Sulfate
Phygon experimental
Contractor
Weston & Sampson
Unspecified
Unspecified
Location
Unspecified
Unspecified
Unspecified
Unspecified
Amount/Dose
Unspecified
0.55 ppm
Unspecified
Unspecified
Unspecified
Unspecified
0.5 ppm
Unspecified
Unspecified
Up to 200 ft into
pond
Entire shoreline
144 lbs at 2 ppm
4 L at 2 ppm
Emergent
20 lbs/acre
herbicide
8/1957
Copper Sulfate
Rotenone
6/6/60
Silvex
6/24/606/27/60
Silvex
Weed & Brush Corp. of
Worcester
Weed & Brush Corp. of
Worcester
Amino Triazole
vegetation
6/30/60 7/2/60
9/60
Sodium
Arsenate
Copper Sulfate
Weed & Brush Corp.
of Worcester
Allied Biological
Center portion of
pond in sections
Spot treatments
4,624 gal at 10 ppm
Unspecified
Submerged
aquatic growths
Emergent Growth
1400 lbs of 0.5 ppm
Unspecified amount
at 10 ppm
Unknown
Entire Pond
600 lbs
Spot treatment
15 gal
15 acres
Unspecified
Unspecified
Control
8/24/61
7/18/62
7/66
Copper Sulfate
Arsenic Oxide
(As2O3)
Dalapon and
Amitrol T
Copper Sulfate
Diquat
Unspecified
Allied Biological
Control
Allied Biological
Control
Allied Biological
Control and
Northeastern Weed and
Brush Control Corp. of
Worcester
Diguat
Arsenic Oxide
(As2O3)
Copper Sulfate
Unspecified
Unspecified
6/68
Copper Sulfate
Unspecified
Spot Blooms
6/69
Copper Sulfate
Unspecified
Unspecified
7/70
Copper Sulfate
Unspecified
Unspecified
7/28/71 to
9/17/71
7/72
Copper Sulfate
Allied Biological
Control
Unspecified
Unspecified
Unspecified
Unspecified
at 7.5 ppm
Unspecified
0.3 ppm
Unspecified
0.3 ppm
Unspecified
0.3 ppm
Unspecified
0.3 ppm
Unspecified
Unspecified
Unspecified
70 lbs
200 lbs
8/67
5/68
Aquathol-K
Copper Sulfate
Unspecified
82
amount
amount at
amount at
amount at
amount at
4.3.4 Gypsy Moth Infestation
In the 1900s, Menotomy Rocks Park and other forested areas throughout Massachusetts
were faced with an infestation of Gypsy Moths. There are chronicles in history books
and the local paper describing the devastation. In 1892, F.C. Moulton of the
Massachusetts Gypsy Moth Commission discovered the effectiveness of lead arsenate
against gypsy moths and lead arsenate grew quickly in popularity [Aurilio, 1992; Hayes,
1954]. Historical records show that lead arsenate was used extensively in the Fells in
Medford, Massachusetts to control the moths. An examination of available information
on the history of Menotomy Rocks Park does not mention the use of this arsenical
pesticide as a method to control gypsy moths, but it seems likely that it may have been a
standard method for moth control in this area. Further investigation should reveal any
significance gypsy moth control procedures had on the amount of arsenic in Spy Pond.
4.3.5 Other PotentialSources
Several other sources are worth investigating in the future based on this study's
conclusions. The foundry or the large market garden located adjacent to the arsenic "hot
spot" (see Section 3.3.3) may reveal historical uses of significant amounts of arsenic.
Also, no information on the fill associated with the expansion of Route 2 could be found.
Sampling of the soil between Route 2 and Spy Pond would confirm if this is a source of
arsenic. The soils adjacent to the railroad (now the Minute Man Bike Path) may be
contaminated with arsenic due to sodium arsenate applications for brush and weed
control. Furthermore, lumber yards and funeral homes use small amounts of arsenic for
preservation purposes. These businesses may add to the total arsenic loading to the Pond.
Finally, historical records mention a pipe connecting Spy Pond to the Arlington
Reservior. This may be a conduit for contaminants from other areas of Arlington.
83
4.4 Conclusions
The investigation both concluded the consideration of some potential arsenic sources and
revealed new sources to investigate in the future. According to sampling results and
historical research, stormwater runoff and weed control applications are not likely the
major source of arsenic input to the Pond.
Several steps need to be taken in the future. This study implicates groundwater as the
major conductor of arsenic pollution. Groundwater and soil sampling around the Pond
need to be conducted in an attempt to discover the plume, if one exists.
84
References
1) Arlington Heritage Trust. (1977) Arlington Celebrates: The Growing Years: 18751975.
2) Arlington Historical Society. Historical Map Collection.
3) Aurilio, A. (1992) Arsenic in the Aberjona Watershed. Massachusetts Institute of
Technology.
4) Chesebrough, E.W. and Duerring, C. (1982) Spy Pond: A DiagnosticStudy 19801981. Massachusetts Department of Environmental Quality Engineering Division of
Water Pollution Control Technical Services Branch.
5) Cortell, Jason M and Associates (1973) Report of Conditions in Spy Pond,Arlington,
Massachusetts:A HistoricalSynopsis. Jason M. Cortell & Associates, Wellesley
Hills, Massachusetts. Prepared for Massachusetts Department of Natural Resources.
6) Duffy, Richard A. (1997) Images of America: Arlington. Arcadia Publishing, Dover,
New Hampshire
7) Gawel, J., Chin, M. (1998) Unpublished Drain Outfall Sampling Results.
Massachusetts Institute of Technology.
8) Harrington, J.M., LaForce, M., Rember, W., Fendorf, S., and Rosenzweig, R. (1998)
Phase Associations and Mobilization of Iron and Trace Elements in Coeur d'Alene
6 5 0 6 56 .
Lake, Idaho. Environmental Science Technology. Volume 32, No. 5. p 9) Ivushkina, T (1999) Toxic Elements in the Sediments of the Alewife Brook and Mill
Brook Watersheds: Spatial Distributionand DepositionalHistory Tufts University.
10) MacLaughlin, K., Gawel, J., Senn, D. and Lukacs, H. (1998) Logbooks for Spy Pond
Fieldwork. Massachusetts Institute of Technology.
11) Massachusetts Executive Office of Environmental Affairs. (1998) MassGIS
Geographic Information Systems Database.
12) Nriagu, J.O., Arsenic in the Environment: Part I: Cycling and Characterization1994.
John Wiley & Sons, Inc. NY, NY
13) Robertson, J., Cassidy, J., Chaudhry, M. (1988) Hydraulic Engineering.Houghton
Mifflin Company, Boston, MA.
14) Sanborn Map & Publishing Company, Limited. (1885 - 1971). State Library of
Massachusetts Special Collections Department
85
15) Shanahan, P., Spink, J., Morales, A. (1997) Review of Recommendationsfor the
Restoration of Spy Pond,Arlington, Massachusetts. HydroAnalysis, Inc., Acton, MA
and MNS Consultants Inc., Wellesly, MA.
16) Senn, David (1998) Analysis of Spy Pond Sediment Core. Unpublished.
Massachusetts Institute of Technology.
17) Senn, D. and Gawel, J. (1999) Unpublished Water Column Data. Massachusetts
Institute of Technology.
18) Spliethoff, H. (1995) Biotic and Abiotic Transformationsof Arsenic in the Upper
Mystic Lake. Massachusetts Institute of Technology
19) Thomas, C. (1999) Personal communication. Lupine Information Systems.
20) United States Geological Survey. (1944) Surficial Geologic Map of the Mystic
Lakes-Fresh Pond Buried Valley Area between Wilmington and Cambridge,
Massachusetts. Scale 1:31,680.
86
Acknowledgements
My list of people to thank seems endless. This is a very challenging program and would
be impossible without the support, assistance and patience of others. First, I would like
to thank the Spy Pond investigation team who not only made this thesis possible, but
made it a truly fun and enjoyable experience: Jim, Heather, and Dave. A special thanks
goes to Cord, who showed extraordinary patience and enthusiasm even after months of
teaching GIS mapmaking to a woman who never can ask enough questions. I would also
like to thank Jim for introducing me the mystery and intrigue of Spy Pond and helping
me stay grounded.
Help throughout the project came in the form of the Parson's Volunteer Rescue Team
including, Megan, Dan, Chris and John, who volunteered to wait for rain that refused to
appear. Also, Dan and Rachel where always willing to assist with sediment sample
preparation and analysis. Finally, I'm grateful to the students of the Hemond Lab, who
welcomed me with open arms, and made the hours of analysis fly by with their humor
and helpfulness.
Other help came from John Durant of Tufts University and Pete Shanahan of
Hydroanalysis, who gave their notes and knowledge on the pond, Mark Shea, of
Arlington Public Works, who spent a morning without complaint assisting a strange
graduate student who wanted samples of catch basin muck, and Lisa Welter, of the
Arlington Historical Society, who came out in a snow storm to share the history of
Arlington.
Finally, I would like to thank my family and friends. It is though their unwavering
support and encouragement that I am able to accomplish my goals and dreams.
87