Quality Assurance Project Plan Including Sampling And Analysis Plan (Page 37 of 67) in pdf

Hunters Point Shipyard Parcel F ESTCP Demonstration Plan

Appendix A: Quality Assurance Project Plan

To assess the depth and homogeneity of the mixed AC in the sediment, the total organic carbon

(TOC) of each cross section will be measured by elemental analysis, as it has been found to be an

effective indicator for the amount of AC added in the sediment. Each cross section will be

homogenized by stirring manually with a stainless steel spatula, and then approximately 1 g of

sediment will be subsampled for elemental analysis. These subsamples will be dried and ground using

an agate mortar and pestle. Duplicate subsamples of approximately 4 mg each will be weighed into

silver boats. Weighed samples will be then acidified twice in situ with 6% sulfurous acid to remove

carbonate phases. These sediment samples will be analyzed for total organic carbon (TOC) using a

Carlo Erba NA1500 elemental analyzer at Stanford University. For well-mixed sediment in Plots D

and F, we expect an average TOC of 3.8 wt.% (original sediment TOC = 1.0 wt.%) with a small

standard deviation among samples within a plot.

Sediment PCB Concentrations

Sediment samples will be extracted three times with sonication in a 50% acetone and 50% hexane

mixture, following a procedure based on EPA Method 3550A. The acetone portion will be removed

and exchanged with hexane by a nitrogen blowdown apparatus. Then, the extract will be concentrated

using a nitrogen blowdown apparatus and cleaned using the same two-step procedure mentioned

previously for the SPMD extracts. The PCB analysis of the resulting sediment extracts will be

performed according to Section A.3.4.1.3.

Aqueous Equilibrium PCB Concentrations

Equilibrium distribution of PCBs between sediment and aqueous phases will be measured by placing

approximately 30 g of activated carbon-treated or untreated wet sediment in 780 mL glass bottles

with 31 ppt seawater and 1 g/L sodium azide (practical grade, Mallinckrodt, Paris, KY) to inhibit

microbiological growth. The bottles will be capped with Teflon-lined caps, shaken, and rotated at

approximately 2 rpm on a roller for 14 d, after which the sediment/water mixture will be allowed to

settle and the supernatant cleared of any floating particles with a Pasteur pipette. Colloids will be

removed using a flocculation procedure described previously (Ghosh et al. 2000). PCBs will be

extracted from the aqueous phase with hexane. The extract will be concentrated by a rotary

evaporator and followed by a nitrogen blowdown apparatus. Extract cleanup will follow the same

procedures mentioned previously for the SPMD extracts. The PCB analysis of the resulting extracts

will be performed according to Section A.3.4.1.3.

A.3.4.1.3 Stanford PCB Congener Analysis

PCB congener specific analysis will be performed using a modified EPA Method 8082. An Agilent gas

chromatograph (model 6890) with a fused silica capillary column (HP-5, 60 m x 0.25 mm ID) and a

micro electron capture detector will be used for analysis. A 5-level PCB calibration table will be prepared

using a known PCB mixture containing 250 µg/L of Aroclor 1232, 180 µg/L of Aroclor 1248 and 180

µg/L of Aroclor 1262 yielding a total PCB concentration of 610 µg/L. The known PCB calibration

mixture has been already obtained from the EPA's National Health and Environmental Effects Research

Laboratory in Grosse Ile, Michigan. Concentrations of individual PCB congeners in this mixture have

been obtained from Mullin. Two internal standards will be used: PCB-30 (2,4,6-trichlorobiphenyl) and

PCB-204 (2,2’,3,4,4’,5,6,6’-octachloro biphenyl), which are not present in commercial Aroclor mixtures.

Using this protocol, 92 PCB congeners or congener groups can be identified and quantified. With this

analytical method, there are some coeluting PCB peaks in the analysis. Where this occurs, coeluting peaks

will be calibrated as a sum of congeners.

A.3.4.2 Analytical/Testing Methods for ERDC

A.3.4.2.1 Extraction of PCBs in Clam and Amphipod Samples

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Quality Assurance Project Plan Including Sampling And Analysis Plan Page 37

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