r-~·-··-----~---·-·------ -------~-----~--~-=··~-~-·"-·-
!
CALIFORNIA STATE UNIVERSITY, NORTHRIDGE
LEVELS OF COLIFORMS IN SHELLFiSH
FROM SANTA MONICA BAY
h
A thesis submitted in partial satisfaction of the
requirements for the degree of Master of Science in
Environmental Health
by
Steven L. Saylors
~
July, 1976
. ,.
___
,_
.
.__
~,-~~~
1
l
The Thesis of Steven L. Saylors is approved•
Dr. R~S. Stasiak
California State University, Northridge
j
!
-------..--------------------"~---·-----·--··-·----·------,.)'
L--~-------~-~----~-
ii
TABLE OF CONTENTS
I
Page
I
vi
!ABSTRACT
,Chapter
i
1
INTRODUCTION
1
STATEMENT OF PROBLEM
HYPOTHESES
2
LITERATURE REVIEW
15
3
MATERIALS AND METHODS .
18
RESULTS
DISCUSSION
4
SUMMARY AND CONCLUSIONS . .
32
5
RECOMMENDATIONS . .
34
. .. .
.REFERENCES
iii
36
LIST OF TABLES
!
Page
!Table
i
i
'
1
WATER TEMPERATURES AND MPN'S FOR TOTAL
AND FECAL COLIFORMS FOR BOTH AREAS
21
2
SUMMARY TABLE FOR THE AN OVA
23
3
SUMMARY TABLE FOR THE ANOVA - Analysis of
the Data from the Hyperion Area
23
4
SUMMARY TABLE FOR THE ANOVA - Analysis of
the Data from the Point Dume Area
24
5
SUMMARY TABLE FOR THE ANOVA - Statistical
Analysis of the Data Comparing the Two
.
30-Foot Depths
25
MPN COUNTS FOR TOTAL COLIFORMS FROM SEAWATER TAKEN AT THE BKR AREA
25
. !
. . . . . .
. . .
. . . .
. . .
. . . . . . . . . . .
6
. . . .
. . . . . . . . .
iv
r
LIST OF FIGURES
Page
iFigure
I
!
I
1
Diagram of Hyperion Outfall Pipe Illustrating Depths and Distances . • . . . . • .
3
Diagram of the Top of the Big Kelp Reef
Showing Depths Versus Distances From
Shore
11
3
Graph of Depth Versus Temperature at the
Hyper ion Area
26
4
Graph of Depth Versus Tempe.rature at the
.
BKR Area
26
2
. . . . . . . . . . . . . ..
. . . .. . . . . . .
. . . . . . . . .
v
. . . .
ABSTRACT
LEVELS OF COLIFORMS IN SHELLFISH FROM
SANTA MONICA BAY
by
Steven L. Saylors
Master of Science in Environmental Health
The soft parts of the common rock scallop, Hinnites
'muZtirugosus, were tested to determine the levels of
sewage pollution indicators (coliforms1.
A positive con-
firmed test for fecal coliforms, as determined by multiple
tube fermentation, was considered as an indication of
sewage pollution.
Two different areas within the Santa
Monica Bay were compared.
One area was near the Hyperion
Treatment Plant outfall pipe; the other was near Point
Dume, where no sewage pollution was thought to exist.
In
each area, water and scallops from three different depths,
viz., 30, 60 and 100 feet, were sampled to determine the
levels of coliforms.
All scallops from the Hyperion area
were found to have very high levels of both total and
fecal coliforms.
The scallops from Point Dume exhibited
vi
the 30-foot depth and the deeper depths at both locations.
This disparity in indicator concentrations.was probably
related to a thermocline located between the depths of 30
feet and 60 feet.
At the Hyperion location a significant
difference in indicator organisms was also found between
' the 60-foot depth and the 100-foot depth.
vii
~~----
1j·
Chapter 1
l
INTRODUCTION
I
:
Shellfish have been associated with the spread of
'
!human disease since 1603 (Bengsch, 1972).
This spread of
:disease is not due to the shellfish themselves but rather
~to
the pollution of their aquatic environment by man's
sewage.
When untreated sewage is dumped into the marine
environment it enters a complicated. system, part of which
includes shellfish.
The term shellfish includes animals
from all of the following classifications: crustaceans,
echinoderms, and molluscs.
are the bivalve molluscs.
The animals of prime concern
They are filter feeders (Russel-
Hunter, 1968) and pump large quantities of water through
their gills in order to strain out small particles of food.
These bivalves are not particular about the particles they
ingest.
Accordingly, they filter out and concentrate what-
ever is present in the water.
If sewage solids are present,
:they too are filtered out and concentrated.
If viable
!pathogens are present in the sewage they will also be
1present in the bivalves.
Sewage and pathogens are not
I
jseemingly harmful to the bivalves, but if the bivalve is
I
·eaten raw by a human, disease can be spread.
The disease
:pathogens that are known to be transmitted by shellfish
!include enteric bacteria such as SaZmoneZZd typhi 3 Vibrio
1
2
.
.
...
r-:~------ _..,__,_.,.....,.w........,.._~-·----~--.,_,-.- ...-,....,.",."""'~..,., _.,,-,,.....,..,.,".=·""""'"'....,.~'·'7>.~>-~
jaholerae, and
th~
agent responsible for gastroenteritis.
l
iAlso enteric viruses such as those responsible for infectious hepatitis have been shown to be associated with
!.shellfish consumption (Bengsch, 1972).
Eating of raw
I
!shellfish, i.e., oysters, scallops,. mussels, etc., is a
f
:common practice in Europe and also for many people here in
!the United States.
The consumption of raw shellfish has
ibeen shown to be the cause of many disease epidemics
· (Earampoorty, 1975).
STATEMENT OF PROBLEM
It would seem reasonable to imagine that with our
modern day technology there would be no sewage pollution
'in the waters of the United States.
.is not the case.
Unfortunately, this
The Santa Monica Bay is a prime example.
The Hyperion Treatment Plant, located at Dockweiler Beach,
just west of Los Angeles International Airport, treats the
sewage for a large part of Los Angeles County.
Approxi-
mately 3.5 million people are served by the plant, with a
daily average of 347 million gallons of sewage handled.
The plan of the plant calls for secondary aereation treatment of all sewage, which would render all pathogens harmless (Callahan, 1976).
However, the plant is not large
enough to handle the tremendous amounts of sewage it.
receives each day.
1
Therefore only about 100 million
lons are subjected to secondary treatment.
gal~
The remainder
; is subjected only to primary treatment (settling), which
--------·--·------·------------------------
.
3
,.......-----·~-------···---"~----·-~·----·-~·~~---···~~··~·-··-··
jremoves only a portion of the bacterial population.
All
!effluent; primary and secondary treated, is pumped out
!through a pipe eight feet in diameter, that is five and
!one-half miles long.
I
.
This results in large amounts of
!sewage, and possibly pathogens, entering the Santa Monica
!
iBay on a daily basis. The depth of discharge is approxi'mately 33 fathoms
:1975}.
(U.S. Department of Commerce Chart 18744,
The depths and distances from shore of the outfall
ipipe are showri in Figure 1.
0 '
Seawater
~
<!.)
<!.)
so
~
s::
•r-1
100
Ocean Bottom
..c
'~
<1.)
,Q
150
200
~------------------------------------------------------~~
1
2
4
3
5
Miles From Shore
Figure 1. Diagram of Hyperion outfall pipe
illustrating depths and distances.
The length of the pipe is designed to take the sewage
out far enough and deep enough to prevent any pollution
from reaching shore (Callahan, 1976}.
The distance from
shore insures that a reasonable amount of dilution will
occur should the currents of the Bay or the phenomenon of
'
'upwelling carry the polluted water back near the beach.
It
4
fisimportantto "Insuretfla:tthebea-cl1
waTers-arecre·an~·anCi······
\
jfree from pollution so that the 25 milliort people that
I
/visit the beaches of Santa Monica Bay each year will be
lprovided with safe bathing (Los Angeles County, 1975).
I1
Depth is the most effective barrier to contamination
!
i
iOf the beach waters.
The Santa Monica Bay exhibits, as
!
'most ocean waters do, a thermocline (Callahan, 1976; Hardy,
1
1970}.
A thermocline is a layer of water where drastic
;temperature change occurs.
The body of water above the
thermocline is generally several degrees warmer than the
body of water below it (Friedrich, 1969).
The average
depth of the thermocline in the Santa Monica Bay is approximately 40 feet
(Callahan, 1976).
This agrees with the
Eastern Pacific average of 15 meters (CAL COFI, 1958} and
also with readings taken in the Atlantic, around England,
of 15 meters (Hardy, 1970).
A thermocline is capable of
acting as a barrier between the two bodies of water it
separates (Friedrich, 1969).
It tends to prevent the
transport of gases, nutrients, particles, and water from
one layer of water to the other.
Any particles of plankton
that are falling in the upper layer of water will tend to
'concentrate at the thermocline (Friedrich, 1969).
It is
this barrier ability of the thermocline that prevents the
influx of sewage into the swimming waters along the beaches
·of Santa Monica Bay (Callahan, 1976).
Even though the
, effluent is slightly warmer than the receiving water at the
J
end of the pipe it will still not be capable of rising or
5
- - - · - - - - - - - - - - - ------·-----~~---·.. ·~~=·-~--~·=··-·
;··-"··--·-·-·'"-"-·-----·--~-
ldiffusing up through the thermocline (Callahan, 1976).
;
l
'
I
l
This
barrie~
phenomenon dictates that pollution will
!normally be held down below 40 feet in depth ~nd almost a
I
~mile from the beaches of Santa Monica Bay..
The Bay is
!relatively flat and slopes off to qeeper depths gradually;
!
!therefore the depth of 40 feet is located quite a distance
i
!from shore.
A direct health problem could exist, though,
;for scuba divers.
An indirect health hazard exists for
i
i
;those ingesting shellfish harvested from the contaminated
region.
Many scuba divers participate in this sport for the
purpose of procuring food for their personal consumption.
They actively hunt fish, crustaceans, echinoderms, and
molluscs.
A prime target that is considered a delicacy is
the rock scallop, Hinnites muZtirugosus (Tasto, 1974).
This bivalve is one type of game that many divers actually
prefer to eat raw.
It is important to realize that rock
scallops are filter feeders.
They live attached to rocks
and are found at all depths from low tide out to depths in
-excess of 30 fathoms (Hancock, 1959).
They are also very
common in the Santa Monica Bay.
Locating rock scallops has been made easy for the
:diving public by the Department of Fish and Game.
!
There
lare several artificial fishing reefs located in the Santa
i
·Monica Bay that were constructed in the early sixties and
,are clearly marked {Carlisle, 1964).
These reefs are
'located in 55 to 75 feet of water and are constructed
6
r~~-------~~-··-·--·-~------~--~---··----------~~.,-·.··'"·~--~~~--
iffiainly of large rocks.
.
I
1
.
!rock scallops.
The reefs are also located below the
I
!thermocline in the Bay.
ildel
I!the
They make an ideal location for
One of these reefs, tpe Marina
Rey reef, is located only 3.4 miles from the end of
Hyperion outfall pipe (Chart 18744, 1975).
1
Another prime location for harvesting rock scallops is
the outfall pipe itself.
The pipe is constructed of con-
crete, a good, hard, porous material that meets the substrate needs of rock scallops perfectly.
Theoretically,
.there could be scallops growing at the very end of the outfall pipe where the sewage is discharged.
However, the
depth at the end of the pipe (198 feet) is too deep for
sport divers to chance.
But a logical maximum depth of
120 feet for sport divers would put them within 1.9 miles
of the end of the pipe (see Figure 1).
The dispersion of effluents is accomplished by many
mechanisms such as dilution, currents, and tides.
Dilution
by itself would be insufficient to move sewage miles in the
short time that pathogens are alive.
The movement of water
:by currents and tides is the fastest,most effective means
'of spreading sewage in the ocean (Stewart, 1971).
Wind
generated currents have been known to flow at speeds of up
1to 7 miles per hour (Friedrich, 1969).
These currents can
[also flow at depths in the same or opposite direction to
1
·the surface currents (Friedrich, 1969).
The movement of
tides within a shallow bay tends to create a sloshing
;motion that helps to mix the water present and in so doing
·---
-------------------~----··•"·-----··--·-·····,_
....
7
fsl?re'a"d -wha-teveris pre sent:-rn-tlie--wa t.er.-"T11emove'inen't·-'"of ... ____ _
jcurrents and
tid~l
action is the probable means of dispers-
i
.
jing sewage dumped into the Santa Honica Bay.
.The disper-
lsion of the sewage could carry it into the areas where
I
;scallops grow and are harvested by divers.
I
l
There are no data concerning the speed of currents
i
'within the Santa Monica Bay.
It is therefore hard to pre-
!diet the distances sewage pollution could be carried while
still in a viable state.
Studies by Savage and Hanes, in
1971, showed that coliform bacteria were capable of living
up to 12 days in seawater.
Coliforms are only used as
indicators of the presence of sewage, but their life expectancy is similar to the pathogens whose presence they indicate (Clark, 1964).
However, viruses are capable of living
·for much longer periods of time (60 days or more) in seawater (Vaughn, 1975).
Considering the-amount of time that
· coliforms and viruses are capable of surviving in se·awater,
it is clear that even with a minimum of water movement that
extensive dispersion could occur.
In the ocean, miles are
small when steady movements over days are concerned.
The discharge of untreated and partially treated
!
sewage beneath the thermocline, along with the known harvesting of shellfish below this thermal barrier indicate
that a potential health hazard exists.
Divers and those
' ingesting the shellfish collected near the discharge are
potentially at risk to the acquisition of a variety of
! intestinal
diseases.
8
~--
l:-t"'
is important to examine thi~-i?~tial-~iih-~~~--~~"~"
!hazard to determine the actual danger of disease transmission.
Examination of the water alone would be insufficient
since the employees of Hyperion already do this, and state
that pollution standards for swimming areas are met
(Callahan, 1976).
However, there is a large difference
:between the standards for swimming areas (2400 mpn/100 ml)
land the standards for shellfish growing areas (70 mpn/100
'ml),
(Foster, 1971; Bengsch, 1972).
The difference is due
to the fact that shellfish concentrate pollutants well
beyond the levels found in the water.
This concentration
may be as high as 60 times the level of the surrounding
water (Bengsch, 1972).
Examination of the shellfish themselves is very important for it can indicate the amount of a pollutant a person
could ingest by eating a shellfish growing in a contaminated area.
scallop.
The best choice for a test animal is the rock
Its ability to live at all depths within the Bay
makes it possible to test all areas and depths.
Other com-
manly eaten shellfish from the Bay, i.e., mussels and
clams, live in a narrow band of depths and·are found close
'to shore.
1 thermocline
They are not found in deep water below the
(Ricketts, 1968).
By choosing an animal that
l
:lives at all depths of concern, greater consistency of
!
'results can be obtained than by using different animals
: from different depths.
'
Testing of different depths will
) indicate whether the thermocline really does restrict the
9
frising,_o:f-~ew~ged.Tscharged -below i~-·~---~--·=·~-",
I
Based on·probable levels of pollution,· two distinctly
!different
areas in the Santa Monica Bay were selected for
I
!analysis.
I
Ioutfall.
l
!
The main area of concern was the Hyperion sewage
Rather high levels of pollution were expected in
this location due to the large
amoun~s
of sewage being
t
!introduced on a daily basis.
The other area selected was
in the waters off of Point Dume.
There should be low
'levels of pollution, if any, in this area since there are
,no sewage outfalls within 4 miles.
The closest sewage out-
fall is from a plant that treats all of its sewage by
secondary methods, and has a relatively small volume of
.flow.
The Hyperion area is located off Dockweiler Beach,
just east of Los Angeles International Airport.
Locations
of possible scallop collection are the-Marina del Rey Fish
and Game Reef, the detached breakwater of Marina del Rey,
and the actual outfall pipe itself.
The first two loca-
tions are constructed of rock and are known by local divers
for their scallop production.
· structed of concrete sections.
The outfall pipe is conAt the joint of each sec-
'tion there is a small crack where scallops can establish a
firm attachment.
There are, in fact, many scallops
attached to this part of the pipe.
There was evidence, in
. the form of fresh scars on· the rocks and the pipe, that
indicate that scallops are being harvested regularly from
;
a~l ·three locations.
---
------·-----------~------··~·---·
.. ·---- ...
10
lection in the Hyperion
area~
There are many scallops
I
!available and finding the pipe is relatively easy.
jancho~
A small
drug along the bottom in a direction parallel to the
I
jshore,will attach itself to the outfall pipe.
The pipe
,sits on the bottom, from a depth or 20 feet, to the final
depth of 198 feet (see Figure 1).
This allows collection
ifrom all depths in the same area.
The breakwater and the Fish and Game Reef were both
tested once.
They presented limitations since they are
very restrictive in depth.
The breakwater is a maximum of
.35 feet deep, while the Fish and Game Reef is located in 65
feet of water.
Both of these
locat~ons
have ample supplies
of scallops and are the target of regular scallop collec·tion by many divers.
The Point Dume area is on the extreme north end of the
Santa Monica Bay.
A reef known to local fishermen as the
Big Kelp Reef (BKR) was selected as the sampling site.
The
reef is located halfway between Paradise Cove and Point
Dume.
It runs in an east-west direction starting in 30
feet of water and extends out to a depth in excess of 250
feet.
The BKR is an excellent fishing reef and until the
ilast few years was very seldomly visited by divers.
l
There
:are an abundance of scallops available here at all depths.
'Due to the lack of people collecting these scallops, most
•of them are very large in size, measuring some 6-10 inches
lin diameter.
This area is gaining in popularity as a diving
~~-- .. -~.~-~~- ... --.~-·---------.---·----------·- - - - - - - - -...- •. ~.__......,.__,_~~~~·~·~-.~·•->.>'
11
are being consumed.
Isewage
The only possible loca·l sources of
in this area are boats and faulty septip systems of
!houses on shore.
j
30'
I
50
;~
Q)
iQ)
!
~
100
150
200
2
Miles
1
Mile
Figure 2. Diagram of the top of the Big Kelp
Reef showing depths versus distances from shore.
Both areas were tested at three different depths--25• 35 feet, 60-70 feet, and 90-100 feet deep.
were chosen as a
respresenta~ive
These depths
cross-section of the
depths to which divers would descend.
Water quality was assessed by testing for bacterial
indicators of pollution.
This was done following the
methods outlined in Recommended Procedures for the Examina:tion of Sea Water and SheZZfish.
The specific method
utilized calls for the multiple tube fermentation test for
the coliform group.
This is the most commonly used test
to indicate the purity or pollution of shellfish.
1
It
should be realized that coliforms are not pathogenic in
themselves, but are recognized only as indicators of recent
1
12
~(c-iart;-1964).
Ijfrom
·coliforms are capable of living
5 to 12 days in seawater, depending on the water tem-
i
jperature and the natural bacteria level of the seawater
!(Mitchell, 1971).
The coliform group includes all of the
l
;aerobic and facultative anerobic, gram-negative, nonsporef
I
:forming, rod-shaped bacteria .that ferment lactose with gas
'
:formation within 48 hours at 35° C.
)of coliforms were tested for,
. coliforms.
Two different groups
i.e. , total coli forms and fecal .
Coliforms are found in the feces of warm-
;blooded animals, the guts of cold-blooded animals, in soils,
.and also on many plants (Clark, 1964).
The total coliform
count includes all types of coliforms from all sources.
'The fecal coliforms are by definition supposed to be only
from the feces of warm-blooded animals.
Unfortunately,
there is no 100% sure way of separating fecal coliforms
from total coliforms.
The elevated temperature test
(44.5° c. for 24 hours in EC media) is capable of eliminating about 91 percent of non-fecal coliforms, but some will
still show positive (Kabler, 1964).
counts should be viewed accordingly.
Therefore all fecal
Of these fecal counts
there is no means at all of separating human fecal
.coliforms from other warm-blooded animal fecal coliforms
(Kabler, 1964).
As a result, the fecal counts could be
misleading as to the amounts of possible disease-containing
sewage.
For the above reasons, it is necessary-to consider
all fecal coliforms as indicators of recent human fecal
pollution (Kabler, 1964).
The presence of human feces
13
[-~-·--·--·- ~-
lmust be considered as indicative of dangerous contamination,
~possible
of spr.eading disease (Kabler, 1964).
Testing for
lcoliforms is the standard method of determining the saniltary quality of shellfish (Standard Methods, 1970). The
l
:maximum
allowable count of fecal coliforms for market shell,.
I
i
!fish is an MPN (most probable number) of 230 per 100 grams
:of tissue.
Also, an approved shellfish growing area has a
median coliform count of not more than 70 MPN per 100 ml.
of· water (Bengsch, 1972).
These stan.dards are based on
the exgmination of the entire animal, excluding shell.
For
oysters, mussels, and clams this is· applicable since the
entire animal is generally eaten.
sent a special situation.
However, scallops pre-
Commercially the only part of
;the scallop processed and sold is the single adductor
muscle, known as the eye (Willbout, 1961).
The eye must be
free of pieces of roe, gut, and shell particles (Homans,
1961).
By consuming only the adductor muscle, the chances
of ingesting pollution are greatly reduced.
Work with the
northern quahaug, Mercenaria mercenaria, by Cabelli and
Heffernan in 1970 showed that Escherichia coli, a fecal
coliform, tended to be concentrated in the digestive gland
and siphon.
The remaining parts of the
c~am
rarely
exceeded or equaled in concentration the levels of E. coli
present in the water.
If this also applies to scallops,
then the majority of people that collect and eat their own
scallops are relatively safe from disease.
Very few people
:eat the entire animal including digestive gland, gills, and
14
.
rg;~;;;ds- .--Ho~;;;t~r;-;r~-pur i ~-th~t-;a't""th~·~·-~-- --~.,,,,
!entire artimal
I
lsta~king
the<
r~w,
as suggested in Euell Gibbonst book,
.
B~ue
Eyed
Sca~~op.
These people ,need to be
I
!assured that they will not be exposing themselves to pos1
!sible disease.
i
HYPOTHESES
1.
There is no significant difference in bacterial indicators of sewage, in rock scallops,
between the Hyperion area and the Point Dume
area.
2.
If a thermocline is
nificant difference
between the layer of
cline and the layer
cline.
3.
Levels of coliforms in test samples do not
exceed accepted standards for water quality
at any of the depths sampled.
4.
The coliform concentrations found in the rock
scallops in the test areas do not exceed the
recommended standards for shellfish.
5.
The coliform levels in the \vaters at the test
areas do not exceed the standards for shellfish growing areas.
present, there is no sigin ind~cator organisms
water above the thermoof water below the thermo-
15
Chapter 2
LITERATURE REVIEW
There is very little information concerning the rock
scallop Hinnites multirugosus.
The only sources were
descriptions of the animal by Tasto in 1974 and Hancock in
1959.
They stated that
th~animal
lives in depths ranging
from low tide out to greater than 30 fathoms.
covei:ed the range of the scallop.
and
~eeding,
They also
In regards to metabolism
no studies were discovered.
Fortunately most of the bivalve filter feeders exhibit
similar feeding, pumping, and filtering characteristics.
R. D. Purchon in his book The Biology of the Mollusca,
describes the pumping action of the mussel Mytilus.
states that M.
He
edu lis pumps an average of 1. 5 liters per
hour at 14° C.; also that M. californianus will pump even
more (5.1/hour) in colder water farther north.
Oysters
showed the highest rate of pumping with averages from 33
to 48 liters per hour, depending on temperature (Bengsch,
;1972).
It is apparent that bivalves will pump large
amounts of water through their gills, depending on the tem\perature and the animal in question.
Due to a lack of
l
'literature on the rock scallop, it is necessary to assume
that it is similar in filteration rate to the rest of the
bivalve group.
16
~---Th~- pumpi~;t~-;I·-hlval;~~comp ii~h~7-two···-thl~g~:
lit supplies
ampl~
water for the respiration of the animal
land enables the animal to filter large numbers of plankton
lJfrom
l
the water as food (Bengsch, 1972).
The particles fil-
tered from the water range in size from 111 on up to larger
,sizes (Morton, 1960).
M.
edu~is
can filter out and retain
particles as small as 1 11 (Purchon, .1968).
Ostria virginica,
;an oyster, filters out particles from 1 11 up to 60 11 in
size.
Anything smaller or larger is not retained by the
animal (Purchon, 1968).
When particles are filtered out they are retained in
the mucous sheets covering the gills (Bengsch, 1972).
This
filtering process results in a net concentration of whatever particles are present in the water (Morton, 1960).
The concentration of particles can be up to 60 times the
levels of the surrounding water (Bengsch, 1972).
If coliforms are present in the water, they will also
be concentrated by the bivalves.
Coliforms fall in the
2-3 11 range, a size within bivalve capacity (Davis, 1973).
This is the reason that shellfish growing areas must have
water that is much cleaner than swimming water (Bengsch,
1972).
Whatever the number of coliforms present in the
,water, it will be much higher in any shellfish present.
{
Viruses present a special situation.
smaller than bacteria (Mitchell, 1971).
They are much
By theory, they
should not be concentrated by bivalves due to their small
:size.
However, viruses have the ability to adsorb to
17
fU- vingtissu~and
in-so-dOing ,=1Ive-aTong--Eime~in. ~seawat'er-
!(Mitchell, 1971).
Hepatitis virus is a common problem with
l
.
.
!shellfish growing in contaminated water
I
(Bengs~h,
1972).
!viruses may be an even greater prob~em than bacteria, due
!
jto a longer survival period in seawater (Mitchell, 1971).
Any sewage dumped into the oceap waters becomes part
of that water and moves with it (Stewart, 1971}.
Stewart,
'in a study of an ocean outfall, found that water movement
{currents) are the main factor in the distribution of
sewage around the outfall.
He found that 100 feet from
the opening {at the surface) dilutions ranging from 42:1 to
92:1 were common.
Ten thousand feet downstream a further
dilution of 10:1 was the average.
The distance sewage
moved was in relation to the speed of the current (Stewart,
1971).
C. W. Chen, in a study of the San Diego outfall,
also found that current was the main factor affecting
spread of sewage.
Information presented by Friedrich in Marine Biology
states that currents are known to exist flowing in all
directions, at all depths, and at many different velocities.
Hardy in the Open Sea states the same thing concerning cur!rents.
Most currents are driven by winds at the surface,
but a counter-current at depth is very common (Friedrich,
: 1969).
!
This would explain the movement of water below the
· thermocline.
~-----~
Chapter 3
I
MATERIALS AND METHODS
Samples were collected from the Hyperion area and the
BKR on 3 different dates.
Equal numbers of samples were
taken from 3 different depths at each location, i.e., 25-35.
feet,
60-70 feet, and
90~100
feet.
The first sampling con-
sisted of 2 specimens taken from each depth; the second,
3 from each depth; the third, 5 from each depth.
In order
to process the samples in the laboratory-immediately after
collection, only one location was sampled on any one day.
Specimens were taken by hand while using scuba diving
gear.
Since scuba diving requires at least 4 to 5 feet of
visibility in the water, collection was attempted only on
days that were relatively calm with clear skies.
With
these conditions the water was adequately clear and sufficient light was available to see when working at the 100foot depth.
As a result, all samples were collected under
• very similar weather and ocean conditions. ·
An attempt was made to only collect scallops that were
; 2 to 4 inches in diameter.
This worked very well at all
: locations and depths except at the 100-foot depth at the
'
• BKR.
Due to the extreme dep·th; the amount of time allowed
·on the bottom is limited to 10 minutes.
Therefore selec-
• tivi.ty \•las reduced to taking what was immediately
18
19
r·-----'
javailable.
---------·----~-'~<--<~w"•--<~·,0<''-~'''--=,',W~'"'
All scallops found at this location and depth
iexceeded
6 inches in diameter.
t
This size differential
should have no bearing on the data as results ·are expressed
MPN (most probable number) per 100 grams of animal.
The scallops were removed from the rocks and placed
in plastic bags while still at the'depth of collection.
,The temperature of the water at each depth was recorded at
this time.
A
u.s.
Divers Aqua-Lung Temperature Gauge was
used to record all water temperatures.
Upon surfacing, the
plastic bags containing scallops were placed in an ice
chest full of ice.
This procedure insured fresh living
samples upon arrival at the lab.
Time from collection to
processing in the lab was approximately 30 to 90 minutes.
The dates of collection were as follows: BKR February 24,
March 16, and March 31; Hyperion March 2, March 30, and
April 13.
The scallops were processed individually according to
the· methods i i Recommended Procedures for the Examination
of Sea Water and Shellfish (APHA, 1970}.
The completed
multiple tube fermentation test was run, using lauryl
tryptose media for the presumptive test, brilliant green
lactose bile broth 2 percent for the confirmed test for
itotal coliforms, and EC media for the confirmed test for
:fecal coliforms.
l
. necessary.
For the completed test 3 steps were
Tubes of lactose broth were inoculated from the
presumptive tubes and examined for gas production.
;Nutrient agar slants were inoculated with material from the
20
p~e-;~p.t;;;~·test ~d examined-;i~pical-iYfu;-g~:~~-·-..~"···"··
l:taining charac.teristics.
1
l
Also plates of eosin methylene
blue were streaked, incubated, and examined for typical
/coliform colonies.
In all fermentation tests that were positive, i.e.,
I
'produced gas, an MPN was determined for that sample from
the appropriate MPN table in Recommended Procedures for the
:Examination of Sea Water and SheZZfish (APHA, 1970).
There was only one problem in using rock scallops for
this
Part of the procedure calls for the
e~periment.
sterilization of the lip of the shell by scrubbing with a
brush and alcohol.
On most bivalves this is rather easy
and effective since their shells are rather smooth.
How-
ever, the rock scallop shell has many radiating ribs and
short spines that make an ideal attachment surface for
encrusting organisms.
pletely
cover~d
Many of the samples taken were com-
with encrusting organisms to the point that
it was hard to determine where the scallop's lip or opening
was.
In these cases a wire brush was used to clear away
all encrustations before sterilization.
RESULTS
Table 1 gives the MPN's of total coliforms and fecal
coliforms for the samples tested.
This information is
presented according to area and depth.
In addition to the
, estimated concentrations for the indicat.or organisms, water
·temperatures at the collection site are presented ..
)
'·~
......,....... ......... ~ -.... ,,.---,-~.--_..._~.....-.~... ~-~-~_
21
r·-·
......... ,..,....,.._.=>..,.>-,,...'<'~¥;tt", ... ~
on--~-~
~--.--~,
Table 1
I
l
WATER TEMPERATURES AND MPN'S FOR TOTAL
AND FECAL COLIFORMS FOR BOTH AREAS
l
I
1
HYPERION -
!
Total
i
1
2
3
3,500
9.000
16,000
4
9,000
5
6
7
8
9
10
16,000
6,000
16,000
6,000
6,000
3,500
Fecal
4
5
6
7
8
9
10
4
5
6
7
8
9
10
Total
Fecal
16,000
16,000
9,000
25,000
25,000
16,000
25,000
25,000
25,000
. 6, 000
9,000
6,000
2,500
2,500
9,000
3,500
2,500
2,500
2,500
2,500
Total
Fecal
35,000
9,000
35,000
35,000
25,000
35,000
25,000
35,000
35,000
25,000
9,000
6,000
6,000
9,000
9,000
6,000
3,500
9,000
6,000
6,000
~- •'<-'•""""~·'·'··~··•· ~-"'·•·-·•"""'~"-'"'"'-.·""c.u--~·F•'
'"
Total
58°
58°
57°
57°
57°
60°
60°
60°
60°
60°
Total
52°
52°
50°
50°
50°
52°
52°
52°
52°
52°
Total
51°
51°
49°
49°
49°
51°
51°
51°
51 o.
51°
.... '
.
--·~
.......
...,_...,._
.._,....,,..____
- -
Temperature F.
0
0
0
0
0
0
0
0
0
0
51°
51°
52°
52°
52°
49°
49°
49°
49°
49°
100 Feet
Temperature F.
Eecal
3,500
2,500
500
800
1,300
2,500
3,500
1,300·
1,300
1,300
~-
60 Feet
BKR -
Temperature F.
59°
59°
56°
56°
56°
59°
59°
59°
59°
59°
Fecal
9,000
9,000
6,000
3,500
800
1,300
3,500
3,500
6,000
6,000
100 Feet
Temperature F.
0
0
0
0
0
0
0
0
0
0
BKR -
Temperature F.
••&.,.-~....._•'-¥'~•·
30 Feet
Fecal
16,000
16,000
2,500
500
9,000
9,000
3,500
16,000
6,000
6,000
60 Feet
HYPERION -
1
2
3
BKR -
Temperature F.
250
250
900
250
900
250
250
900
250
250
HYPERION
1
2
3
30 Feet
0
0
0
0
0
0
0
0
0
0
v~•---~
~·--~~-·'""•-c-•
50°
50°
51°
51°
51°
49°
49°
49°
49°
49°
.Jo~
·•
~·
.
-~·"
··-~···"
__ ,_- ...
-
22
~---T~ d;t"; were te-;t~;d~-~g-~-f;;t-o~ial-·d~s-ig;;-f~;;""o""~""w·""
I
!analysis of vari~nce.
The least squares method was used to
l
·reduce the error term to a minimum.
Comparisons were made
between the MPN' s for tc>tal coliforms of one area versus
the other, the 30-foot depth versus all deeper depths, and
the 60-foot depth versus the.lOO-foot depth.
By analyzing
.in this wav differences that existed between locations or
depths were distinguished.
In the factorial analysis of variance of the MPN's for
total coliforms from the scallops, the following symbols
were used to designate certain comparisons:
yl
=
the comparison of the two areas relative to
total coliforms.
y2
=
the comparison of the 30-foot depth with all
deeper depths regardless of area.
y3
=
the comparison of the 60-foot depth with the
100-foot depth regardless of area.
y4 + 5 = the intersection between the factors.
e
=
y
= the
the error term.
deviation scores for the raw data.
The results of this analysis are pr~sented in Table 2.
The data in Table 2 indicate three important points:
(1) yl is significant,
is also significant.
probability level.
(2) y2 is significant, and {3) y4 + 5
They are all significant at the 0.01
Since the interaction terms were sig-
nificant, additional evo.luation of relevant factors was
i
required.
A graph of the means at the two locations shows that
the means cross, giving a dis ordinal interaction.
This type of
23
,-~-~--
------------------------------------------Table 2
...
~--_....,_ _,..,""""'"'~"''""""'''
~
SUMMARY TABLE FOR THE ANOVA
!====================================================================
!source
lI
Sums of Squares
d.f.
Mean Square
F
R
y1
y2
3,101,766,000
1
3,101,766,000
84.7
.64
360,810,720
1
360,810,720
9.8
.22
y3
108,570,240
1
108,570,240
2.9
.12
_y4 + 5
1,821,376,980
2
910,688,490
24.8
.49
e
1,976,327,803
54
36,598,662
y
7,380,942,593
59
interaction dictates that the two locations be analyzed
separately.
By using the same analysis of variance for one
factor with three levels, and doing each area separately,
more specific information was obtained.
Analysis of the data from the Hyperion area yielded
the results presented in Table 3.
Table 3
SUMMARY TABLE FOR THE ANOVA
Analysis of the Data from the Hyperion Area
Source
l
Sums of Squares
d. f.
Mean Square
R
F
1,601,873,280
1
1,601,873,280
27.2
.66
460,800,000
1
460,800,000
7.8
.35
e
1,586,600,000
27
58,759,260
y
3,648,860,540
29
y30
y60-90
These results show that a significant differenceexists
between not only the 30-foot depth and deeper
dept~s,
but
24
.. ..
r-~------~-----·-· --·----·---·~-·----~··~--·--·--·~~-----~~~-- "~
also between the_ 60-foot depth and the 100-foot depth.
1
i
!These differences are significant at a probability level of
I10.01.
Analysis of the data from the Point Dume area yielded
l
I
ithe results shown in Table 4.
Table 4
SUMMARY TABLE FOR THE ANOVA
Analysis of the Data from the Point Durne Area
·Source
Sums of Squares
d. f.
Mean Square
F
R
y30
172,992,240
1
172,992,240
12.46
.53
y60-90
45,300,500
1
45,300,500
3.26
.27
e
374,745,413
27
13,879,459
y
608,394,643
29
These results show that there is a significant difference between the 30-foot depth and the deeper depths at a
probability level of 0.01.
It also shows that there is no
significant difference between the 60-foot depth and the
100-foot depth.
A significant difference in total coliforms exists
between the different areas.
However, there did not appear
to be any difference between the shallow depths (30 feet)
of the two areas.
Table 5 presents the results of the
30-foot data for both collecting areas.
The analysis shows
, that there is no significant difference between the 30-foot
depths of the two different areas.
25
r · - ·-------
Table 5
SUMMARY TABLE FOR THE ANOVA
Statistical Analysis of the Data Comparing
the Two 30-Foot Depths
1
i====================================================================
jSource
Sums of Squares
Mean Squar-e
d.f.
y
1,056,250
1
1,056,250
e
441,625,000
28
15,772,321
y
483,237,500
29
R
F
.06
The seawater was also tested at each area to determine
the quality of the water by itself.
once at each area and depth.
This was done only
The testing date was the same
as the last scallop collecting date for each area.
Unfor-
.tunately the samples for the Hyperion area were destroyed
accidentally while in transit from the collecting area to
the lab.
Therefore only MPN's from the BKR are available
for review.
Table 6
MPN COUNTS FOR TOTAL COLIFORMS FROH SEAWATER
TAKEN AT THE BKR AREA
30 Feet
60 Feet-
100 Feet
5/100 m1.
3/100 ml.
3/100 ml.
Figures 3 and 4 show the temperatures in the collect; ing areas as related to depth.
In both areas the thermo-
cline is located between 30 feet and 60 feet.
This thermal
26
60
.. - -....
59
58
(J)
(J)
'!-f
0.0
(J)
0
\
-----\
\
57
U'l
.
------
March 2
March 30.
......
April 13
56
+J
•r-1
(J)
~
~
(J)
55
54
!-f
"@ 53
J:L.
\.::_ ~--= ::;...·.-~ ;;..; :..·..: :..-.:..:.,:. :.::..:..:. -:..-..::
52
51
50
,49
48
30
60
100
Depth in Feet
Figure 3.
Graph of depth versus temperature at the Hyperion area.
60
59
U'l
(J)
(J)
!-f
0.0
(J)
0
(J)
!-f
;:I
+J
cd
!-f
(J)
0..
s
(J)
E-
+J
•r-1
(J)
..r::
~
(J)
!-f
..r::cd
1:-L.
__ ..,_,._,.. . _
February 24
March 16
58
------
57
....... March 31
56
-----
55
'
54
53
-,_
52
51
so
'\
49
'- -~ - ...
--- -- ------
-- - ·- - - -- - - -- - -- ----
48
30
60
100
Depth in Feet
Graph of depth versus temper; aFigure 4.
ture at the BKR area.
27
rb~;i·~;--;;-·~~~~~1 mov~nt-was-preS'~nt:On~ll-~~~;piing·~····-·»;
days.
The location of the thermocline agrees with the
!California Cooperative Oceanic Fisheries
!<cAL
Inves~igation
COFI) studies conducted along the coast and also with
I
ithe measurements made by the employees of the Hyperion
!
Treatment Plant.
DISCUSSION
The two study areas are generally similar in water
conditions, but the influence of man and his sewage has
added a new dimension.
By introducing sewage effluent at a
depth of 198 feet in the Hyperion area the total coliform
distribution is reversed, i.e., the concentration of these
;bacteria increases with depth and distance from shore.
The
:Point Dume area can be considered a natural condition due
to a minimal impact by man.
In this latter area numbers of
coliforms decrease with depth and distance from shore.
The
large number of coliforms introduced with the sewage effluent in the Hyperion area produces coliform concentrations
in the water which are extremely high when compared with
the normal situation.
At both locations a statistically significant difference in coliform concentrations was found between the 30-
i foot depth and the deeper depths.
This difference was
'
:shown to be related with the thermocline, which was found
·to be present between 30 feet in depth and 60 feet in depth.
It is possible that the thermocline was responsible for the
28
,-~-~-"·~···~---·~~~·-..~---~-- ---------·--·-·~------·--~--~·-·-·--·.. ·-··~····~--.-~.. ., ...... ~··•'>• ............... ..
!difference by acting as a barrier to downwards· dispersion
1in
the Point Dume area and conversely to upwards dispersion
lin the Hyperion area.
I
Another factor must also be considered.
This variable
i
(is distance from the source of the coliforms.
In the Point
:nume area all coliforms found were of the non-fecal
;variety.
Non-fecal coliforms are considered to be from
soil and/or plants.
The Point Dume location is not heavily
populated by humans.
Therefore there are still large areas
of uncovered soil that are subject to wind and rain erosion.
This exposed soil is probably the source of the
coliforms found in the scallops taken from this location.
As the soil is blown or washed into the ocean it is diluted
as it spreads out to sea.
Therefore the farther from shore,
the more diluted the soil coliforms.
from shore, the deeper the water.
Also, the farther
It follows that as the
coliforms are carried farther out to sea and diluted, the
fewer the counts that would be found in the water and
resultantly the scallops.
The Hyperion area is completely different.
neighboring shores are heavily
p~pulated
'very little soil is left unexposed.
is out of the west, or on shore.
soil tends to be blown inland.
The
with humans and
The predominant wind
Therefore, any exposed
Although some coliforms in
this marine environment undoubtedly originate on land, the
imain source of coliforms seems to be the Hyperion outfall.
The data show that as distance from the outfall increases,
29
jthecOiifo;;.
c;;~tsdema:se(seeFig~tth~---·
IHyperion location a statistically significant difference in
!coliform concentrations was found between all ·three depths.
!This difference probably was due in part to the dilution as
I
jpollutants are dispersed vertically and horizontally.
This
j
part of the Santa Monica Bay -is shallow and larger horizontal distances must be traveled to change depths.
In
·fact, almost three-quarters of a mile separates the differ-ent depths that were sampled.
Therefore horizontal disper-
sion is probably more important than vertical dispersion in
producing the reduction in coliform concentrations which
were noted.
Determining which fac·tor, distance or thermocline,
predominates will be left to future studies.
Vertical
(surface to bottom water) sampling of the marine water in
the test area would help to clarify the significance of
these factors.
The data taken in this study does not
specify which factor is dominant, but both must be considered as important.
An especially interesting aspect of the data is the
fecal coliform counts.
Not a single fecal'coliform was
'found from scallops taken at the Point Dume area.
This
leads one to believe that the area is indeed clean and
unpolluted by man.
Water contact sports in these waters
seem to entail no health hazard due to the presence of
enteric pathogens.
Even the collecting and consumption of
ga.me should be considered safe and t..>lorry free.
30
r-~-Thef~~li~-;ta~ion found in the
------:~--"~-~-~~~---~--
Hyper ion area d.eserves special notice.
.
~·-
All of the scallops
!taken and tested exhibited fecal coliform counts above the
!maximum level allowable for the marketing of shellfish.
I
!
)In fact, all of the scallops taken from the two deeper
l
;depths had counts that were ten times in excess of the
allowable level.
If these levels are representative in the
area, it is highly possible for some unsuspecting person
:to take and consume shellfish from these waters and-contract a serious intestinal disease.
Levels of fecal coliforms found in the shellfish
taken from the Hyperion area justify testing for specific
·enteric pathogens.
Testing for pathogens might answer
questions about the degree of health hazard involved.
This
.study has shown that bacterial indicators of sewage pollution are present in high numbers.
Because of the large
numbers of total and fecal coliforms, the presence of
pathogens must be assumed.
The State Regional water Quality Control Board and
the Federal Environmental Protection Agency have imposed
new water quality standards that would require 100 percent
'secondary treatment of all sewage handled by the Hyperion
;Treatment Plant (Evening OutZook, May 12, 1976, p. 1).
t
:unfortunately some of the people that are served by the
i
'plant are opposed to the cost of upgrading the system,
_which has been estimated at $194 million.
The Santa Monica
, City Council has demanded that the two above agenci:es prove
31
r,~-~---·---·o<--~·-----·-··--·-·-----------~----~·----·-"-····-···-~-~~~-·-"--·-···'·····-·
,.,,....... .
tthat the sewage discharge is harmful to the fish and marine
l
!environment before charging them their share of the upgrad-
ling costs (Evening Outlook, May 12, 1976).
What they have
!not considered is the potential danger to man and that
i
isecondary treatment would eliminate almost all pathogens in
I
.·the sewage.
---~--------------·----·-··~~-·~''·
Chapter 4
SUMMARY AND CONCLUSIONS
This study has demonstrated the following:
1.
That a thermocline does exist in the Santa
Monica Bay between the depths of 30 feet and
60 feet;
2.
The thermocline appears to act as a barrier
to the vertical movement of pollution indicator bacteria;
3.
That excessive numbers of coliforms, total
and fecal, are present in the Hyperion area
(especially below the thermocline);
4.
That there was no significant difference
between the surface waters (above 30 feet in
depth) of the two areas;
5.
That distance from source of coliforms is
important relative to the concentrations of
coliforms;
6.
That the rock scallop Hinnites multirugosus
is an excellent shellfish to test for pollution indicators when depth is an important
factor; and
7.
That the sewage effluent discharged into the
Santa Honica Bay may represent a serious
health hazard to both divers and to those
who consume their game.
The above points describe what this study has shown,
but of equal importance are the questions raised by this
:study.
There are many important questions that need to be
• addressed.
has
be~n
The fact that pollu·tion indicators are present
shown.
The null hypothesis that no difference
'
. e.xists bet'Vveen the two areas has been rejected.
32
The
33
_forsl1eii£'fsli____ ,~__,., . """:
fh:ypothe;is~·-thatwaterquailtystand.arcts..
!growing areas·is
Iibe
I
answered.
~et,
needs more information before it can -
The levels of fecal coliforms
p~esent
!scallops were well above acceptable standards.
I
(thermocline does exist and play a
~ole
in the
And a
in the movement of
!
;particles vertically through the water layers.
But how
1
effective is the thermocline in restricting particle move-
ment?
How polluted is the water and how much do the seal-
lops concentrate the pollutants?
What types and how viable
·are the pathogens present in the sewage dumped?
r----·~
!
I
I
Chapter 5
RECOMMENDATIONS
Studies should be conduc-ted to answer the following
questions.
How effective is the thermocline?
A series of
water samples should be tested from each of many different
-depths to determine the levels of particles above and below
:the thermocline.
This should tell if it really restricts
the movement of particles.
The levels, types, and viability of ·specific disease
pathogens should be determined for the waters and shellfish
in the Hyperion area.
If viable disease pathogens are
present, then a public information program should be conducted to educate the public of the danger present.
The
type and effectiveness of the sewage treatment plant should
be upgraded to insure that a possible disease spread will
not occur.
The upgrading of the Hyperion Treatment Plant is
already being considered for the near futur~, but public
sympathies are leaning toward saving monies rather than
upgrading.
The possible health impact should be considered
all important.
Saving a few dollars could mean loss of
life.
Another question to be answered is the amount of dis!persion ·the sewage effluent undergoes.
34
How far does it
35
r;;~~=ho~ fas~e answers to thes~~ue~~i~·~~-;ii~""-·w··
l
frell the extent of the pollution problem.
~-
Many questions remain unanswered at this ·,time, but
ihopefully they will be answered in the near future, before
l'a
j
problem develops, such as disease, that cannot be cured.
------··-- - - - ·
r~-·-·
~---=--<'j
l
I
I
REFERENCES
!
!
!American Punlic Health Association. Recommended Procedures
I
for.; the Examination of Sea Water and Shellfish.
4th
t
ed.; New York, 1970.
Bengsch, H.
"The nature of shellfish and ecological factors contribute to their role in food borne human
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..
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!
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f
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38
,bi
fTa~to ;.,·R~,N~ne
v7:L;~~r~ c~1i~i~~~i~-~;;~:;:~,~-~-"l
Marine Resources Leaflet No. 6, State of California.
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