heavymetals-02232006-wirgau.doc
a. Four groups collected data using different methods. Consult descriptions
below for details.
b. PI – Joe Wirgau
Integrated Laboratory – CHEM ___
For a more detailed description inquiries should be directed to Dr. Joseph Wirgau
(jiwirgau@radford.edu, 540-831-5650)
Unresolved questions regarding these data:
group 2 – which samples are soil and which are water?
Which blanks didn’t meet criteria, and which were not determined?
c.
Column 1 – sample
Data are nominal. Each sample is given a unique identifier, arbitrarily, starting with 1.
Column 2 – old sample
Data are nominal. These are the names of samples assigned by groups, who originally
used different naming systems. These names are needed to find spatial locations on the
appended maps.
Column 3 – sample type
Data are nominal. Soil samples are denoted “soil” and aqueous samples are denoted
“water”.
Columns 4-17 - e.g, Nitrate
NitrateCI
Data are continuous. The first column in each pair describes the chemical being
analyzed. Data are reported in parts per million (ppm). Values below the detection limit
are denoted with a “<” value. The second column in each pair is a 90% confidence
interval for that particular chemical.
Column 18 – pH
Data are continuous. pH values as read by instrument.
Column 19 – Specific Conductance
Data are continuous. Data are values as read by field instrument, and are expressed in
uS/cm at 25C (microsiemens per centimeter at 25 degrees Celsius).
Columns 20 -26 - e.g., Nitratespike
Data are percents, expressed as decimals and calculated as: Percent Spike Recovery =
experimental value / known value.
Columns 27-35
- e.g., Nitrateblank
Data are mixed format – nd = “no data”, “0” = blank didn’t read below detection limit,
“1” blank read below detection limit, and a numerical value indicates a specific reading
from a blank.
Column 36 – group
Data are nominal. This is a code to designate which group (1-4, see methods below)
collected which data.
METHODS COMMON TO ALL GROUPS:
Sample Collection:
All soil samples were collected in 4 oz glass jars pre-washed with surfactants, DI water,
0.1 M HCl, and DI water again until the pH of the rinses was the same as the DI water.
All water samples were collected in 1 L plastic bottles pre-washed with surfactants, DI
water, 0.1 M HCl, and DI water again until the pH of the rinses was the same as the DI
water. Soil samples were collected from the top few inches of soil and dried in an oven
at 40 oC. Within an hour of sampling, water samples were analyzed for pH (2 point
calibration with pH 4 and 7 buffer) and specific conductance (calibrated with 0 and 1000
S/cm standards). Water samples were then filtered (Fisher Brand Filter Paper P8) and
separated. 5 mL of concentrated nitric acid per liter of solution was added to the portion
to be analyzed for inorganic analytes. All samples were stored in the dark at 7oC.
Soil pH Determination:
Adapted from SSSA Book Series: Methods of Soil Analysis: Chemical Methods. Part 3.
1996. D. L. Sparks, editor, J. M. Bartels, managing editor.
10 g of dry sample was mixed with 10 mL of DI water and the pH of the resulting
solution was determined with pH probes (calibrated with pH 4 and 10 buffer solution).
Metal Determination in Soil Samples:
Followed EPA SW-846 Method 3051.
Briefly, 0.5 g of sample and 10 mL of concentrated HNO3 was heated in a closed
container by microwave to 175 oC over 5.5 minutes and held at that temperature for an
additional 10 minutes. The solutions were filtered diluted to 50 mL and analyzed by
FAA.
Metal Determination in Water Samples:
Followed EPA SW-846 Method 3015.
Briefly, 45 mL of sample and 5 mL of concentrated HNO3 was heated in a closed
container by microwave to 160 oC over 10 minutes and then increased to 170 oC over the
next 10 minutes. The solutions were then analyzed by FAA.
Nitrate and Nitrite Determination:
Adapted from SSSA Book Series: Methods of Soil Analysis: Chemical Methods. Part 3.
1996. D. L. Sparks, editor, J. M. Bartels, managing editor.
Samples were extracted by shaking 5 g of soil with 50 mL of 2 M KCl for one hour. The
resulting solutions were decanted and filtered.
For detection a copperized cadmium column was prepared by the following method. mix
50 g Cd with 250 mL 6 M HCl for 1 min. Decant liquid and rinse Cd with DI water.
Mix Cd with 250 mL of 20 g / L CuSO4.5H2O solution for one minute then decant and
rinse. Add an additional 250 mL of 20 g / L CuSO4.5H2O solution for one minute and
again decant and rinse. Load resulting solid into a column and fill with a solution of 5g
NH4Cl / L. Make sure to always keep the column wet.
For each sample 1 mL of a solution containing 200 g NH4Cl / L and 5 mL of the sample
were loaded onto the column and eluted with 75 mL of a 5 g NH4Cl / L solution into a
100 mL volumetric flask. To the eluted solution 2 mL of a 5 g sulfanilamide / L in 2.4 M
HCl solution(store cold) was added. After 5 minutes, 2 mL of a 3 g N-(1-naphthyl)ethylenediamine dihydrochloride in 0.12 M HCl solution was added (store cold and keep
out of light). The solution was then diluted to 100 mL and after 20 minutes analyzed by
UV-vis spectroscopy (peak centered on 540 nm).
Note: standard curve should range from solutions containing 2 to 20 g of nitrate.
Phosphorus Determination:
Adapted from SSSA Book Series: Methods of Soil Analysis: Chemical Methods. Part 3.
1996. D. L. Sparks, editor, J. M. Bartels, managing editor.
Phospohrus was extracted from the soil by combining 2 g of sample with 30 mL of 70%
HClO4 and heating to 130 oC. Once most of the dark color dissipates the solution was
heated at 203 oC for 20 minutes, cooled and diluted to 250 mL. A portion of this solution
was transferred to a volumetric flask and combined with 5 drops of 0.25% p-nitrophenol
indicator. The pH of the solution was adjusted with NaOH until the solution changed
from a clear to yellow color.
Phosphorus detection was accomplished using the ascorbic acid method. Solution A –D
A = 2.5 M H2SO4
C = 2.728 g K(SbO).C4H4O6.1/2H2O / L
B = 40 g / L (NH4)6Mo7O24.4H2O
D = 0.1 M ascorbic acid
were prepared and mixed using 50 mL of solution A, 15 mL of solution B, 30 mL of
solution D and 5 mL of solution C (solutions A, B, and C may be stored solution D
should be made fresh each day). 8 mL of this resulting mixture was added to 42 mL of
the sample (yellow solution from above) and after 10 minutes the UV-vis spectrum was
collected (peak centered on 880 nm).
Note: standard curve should contain 8 mL of the mixed solution with 42 mL of a solution
containing from 2 to 40 g of phosphorus.
GROUP 1 METHODS:
1)
2)
3)
Samples collected 2/23/06. Data generated from 2/23/06 to 3/31/06 by Eric
Eberhardt, Robert Moore, Melissa Page, and Carmen Reedy
Sample W7 was analyzed in triplicate.
A map of the sampling plan is included below and P denotes the location of
preexisting poles in the wetland.
GROUP 2 METHODS:
Samples collected 2/23/06. Data generated from 2/23/06 to 3/31/06 by Mark Bouley,
Robin Pulliam, Emily Ward, and Kyle Wilmsmeyer
GROUP 3 METHODS:
Samples collected 2/23/06. Data generated from 2/23/06 to 3/31/06 by Stephanie Clary,
Mary Crawford, Danielle Underwood, and Kaleb Woldeamanuel
Circled numbers indicate that both water and soil samples were collected at that site.
GROUP 4 METHODS:
Samples collected 2/23/06. Data generated from 2/23/06 to 3/31/06 by Ashley Anderson,
Julia Hasty, Jonathon Patterson, and Sara Sturgill.
Red letters indicate a soil sampling site and blue numbers represent a water sampling site.