The concentrations of acid volatile sulfides (AVS) and simultaneouslyextracted metals (SEM) were 

 determined in the samples. The analytical methods employed selective generation of hydrogen sulfide 

 by acidifying the sample with IN HC1, cryogenic trapping of the evolved H2S, and gas chromato- 

 graphic separation with photoionization detection. This method gives high sensitivity, low detection 

 limits and very limited chemical interference with minimal sample handling. The AVS analytical 

 system is made of glass and Teflon because of the reactivity of sulfide with metals. The filtered acid 

 solution resulting from the AVS analysis was subsequently analyzed for SEM using graphite furnace 

 atomic absorption, cold-vapor atomic absorption, and inductively coupled mass spectrometry. 



Sediment samples were analyzed for total organic carbon (TOC) and total carbonate (TIC) by Global 

 Geochemistry Corporation, Canoga Park, CA. Before the samples were analyzed, LECO filtration 

 crucibles were precombusted for at least 2 hours at 450°C and allowed to cool. Between approxi- 

 mately 175 mg and 250 mg of dried, finely ground and homogenized sample was placed in a pretreated 

 crucible, and 6N HC1 added to remove inorganic carbon. After approximately 1 hr, deionized water 

 was flushed through the crucible removing the acid, and the sample was dried overnight. Immediately 

 prior to sample analysis, iron and copper chips were added to accelerate the combustion. A LECO 

 model 761-100 carbon analyzer was used to determine both the TOC and TIC content. The analyzer 

 converts all carbon in the sample to CO2 at high temperature in the presence of oxygen. The CO2 was 

 then quantified by thermal conductivity detection. Before sample analysis for TIC, the filtration cru- 

 cibles were precombusted for at least 2 hrs at 450°C and allowed to cool. Between approximately 175 

 mg and 250 mg of dried, finely ground, homogenized sample was placed in a pretreated crucible, and 

 the sample placed in a 450°C oven for 2 hrs to remove organic carbon. 



The methods used to determine sediment grain size are those according to Folk (1974). Briefly, coarse 

 and fine fractions were seperated by wet-sieving. The fine fractions (silt and clay) were further sepa- 

 rated by suspending the sediment in a deflocculant solution and taking aliquots of the settling sediment 

 at timed intervals after the solution was thoroughly mixed. The coarse fraction (sand and gravel) was 

 dried and then separated by sieving through a 2 mm screen. 



Chemical Analyses: Phase 2. In Phase 2 of the study, chemical analyses were performed by the 

 National Biological Service, Midwest Science Center laboratory in Columbia, MO. Analyses were 

 performed for total trace elements; SEM, AVS, PAHs; chlorinated pesticides; PCB congeners; and a 

 number of dioxins and furans. 



Five-gram subsamples of wet sediment were analyzed for SEM/ AVS by treatment with 100 ml 2N HC1 

 for 1 hr in a nitrogen atmosphere. A sulfide-specific electrode was used to measure sulfide liberated 

 from the HC1 treatment. The remaining sediment and acid was filtered through a 0.4 um polycarbonate 

 membrane for metals determination. A second 5 g subsample was taken for analysis of percent mois- 

 ture by oven-drying at 95° C. The remainder of the sample was lyophilized to a constant weight and 

 the dry sediment was utilized for digestion and analysis for total metals and organic carbon. A portion 

 of each filtered SEM extract (6 mL) was diluted with 5.7% nitric acid prior to Zeeman furnace atomic 

 absorption spectroscopy (AAS) to reduce the high chloride ion matrix. Another portion of the SEM 

 extract was similarly diluted and stored in a glass container, which was later used for the determination 

 of mercury by flow injection AAS. A final portion of the SEM extract was subjected to a nitric acid wet 

 digestion/magnesium nitrate dry ash procedure to prepare a digestate suitable for the determination of 

 arsenic and selenium. 



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