15_ 



dual-frequency (100 kHz and 500 kHz) towfish. The acoustic returns were relayed to an 

 EdgeTech 380 data recorder and 260 thermal printer to produce images of the bottom 

 features. The side-scan sonar survey lanes were spaced at 100 m intervals for 150 percent 

 bottom coverage. Bathymetric readings also were collected during the side-scan sonar 

 survey. Navigation data were obtained in NAD83 using DGPS. Similar to REMOTS® 

 data, the positions were converted to NAD27 for reporting purposes. 



2.7 Sediment Grab Sampling 



A series of ten sediment grab samples were collected from the identified potential 

 reference area, SE-REF. Prior to the collection of each sample, the grab sampler, sub 

 cores, bowl, and utensils were washed thoroughly with alconox and sea water, and then 

 rinsed with acetone. A 0. 1 m^ Young-modified Van Veen grab sampling device was 

 deployed at random locations within a 300 meter radius of the center. The grab samples 

 were brought on deck and described. Two titanium cores were used to extract four 

 subsamples of the grab sample, which were then homogenized in a stainless-steel bowl. 

 Next, the sediments were placed into labeled, 8 oz and 4 oz pre-cleaned containers from 

 the laboratory. The 8 oz containers were designated to be used for geochemistry analyses, 

 and the 4 oz were to be used for grain size analysis. The containers were sealed with 

 electric tape and placed in a cooler with ice for storage and transport to the lab. 



2.8 Laboratory Analyses and Quality Assurance/Quality Control Results 



This section describes the methods used for physical and chemical sample 

 preparation, extraction, and analyses of the grab samples. Samples were analyzed for all 

 chemical parameters by the Woods Hole Group Environmental Laboratories (WHO), 

 Raynham, MA. The methods used for analysis of each type of analyte are listed in 

 Table 2-1 and are described in detail in Test Methods for Evaluating Solid Waste EPA 

 SW-846 (EPA 1997). Grain size was analyzed using American Society for Testing and 

 Materials (ASTM) Method D422-63 by Normandeau Associates, Bedford, NH. 



2.8.1 Sediment Grain Size and Total Organic Carbon 



Grain size analyses were conducted using American Society for Testing and 

 Materials (ASTM) Method D422-63. A sieve analysis was performed in which the sample 

 was separated into size fractions of greater than 62.5 mm (<4 phi; sand and gravel), and 

 less than or equal to 62.5 mm (>4 phi; silt and clay). The gravel and sand fraction was 

 subdivided further by mechanically dry sieving it through a graded series of screens. The 

 wet sieve and dry sieve fractions less than 62.5 mm (silt and clay) were combined for each 

 sample. The silt and clay fraction was then subdivided using a pipet technique based upon 



Monitoring Cruise at the WLIS Disposal Site, September 1997 and March J 998 



