2.3 Sediment Sampling and Analysis 



Triplicate sediment samples were collected at the WLIS 

 "A" disposal mound and the Reference station using a 0.1 m 2 

 Smith-Mclntyre Grab Sampler. Six polycarbonate plastic core 

 liners (6.5 cm ID) were pushed into the sediment grab sample and 

 extracted; the six cores were combined and placed into bags for 

 subsequent chemical and physical analysis by the NED laboratory. 

 The top 2 cm of the cores were bagged for separate analysis to 

 determine whether the surface sediment was relatively more or 

 less contaminated than the deeper sediment due to the desorption 

 of contaminants or the deposition of cleaner material. The 

 samples were kept cold and returned to the NED laboratory where 

 they were stored at 4°C until analyzed. Parameters measured 

 included grain size, trace metals, and several organic 

 constituents . 



Sediment analyses were conducted using methods 

 described by the U.S. Environmental Protection Agency (Plumb, 

 1981) . Mercury analysis was performed using acid digestion and 

 cold vapor atomic absorption spectrophotometry; arsenic analysis 

 was accomplished using acid digestion and gaseous anhydride 

 atomic absorption spectrophotometry. The other trace metals (As, 

 Pb, Zn, Cr, Cu, Cd, and Ni) were analyzed using acid digestion 

 and flame atomic absorption spectrophotometry. 



Carbon, hydrogen, and nitrogen analyses were conducted 

 with an autoanalyzer using a combustion technique. Oil and 

 grease measurements were made by extracting the sediment with 

 freon and then analyzing the freon by infrared spectrophotometry. 

 PCBs were extracted with hexane and also analyzed by electron 

 capture gas chromatography. 



2.4 Benthic Community Analysis 



Quantitative benthic samples were obtained with a 

 Smith-Mclntyre grab at the center of the WLIS "A" mound and the 

 Reference station. Five sediment samples were collected and 

 sieved onboard the research vessel through nested 2 and 0.5mm 

 mesh screens. The material retained on the sieves was preserved 

 with buffered formalin for later sorting and identification in 

 the laboratory. Only three of the samples from each of these 

 stations were analyzed while the remaining two were archived for 

 future reference if necessary. A small subsample of each grab 

 was collected for grain size analysis by the NED laboratory using 

 a 3.0 cm inner diameter core tube. A visual description of each 

 sediment grab was recorded prior to sieving. In the laboratory, 

 benthic samples were stained with 0.2% rose bengal and sieved on 

 1.0 and 0.1 mm screens immersed in water. All samples were 

 analyzed under the supervision of Mr. Sheldon Pratt at the 

 University of Rhode Island. 



