grid was centered over CS-90-1, and the sixty-six-station orthogonal grid that was used in 

 1990 was repeated in June 1991 (Figure 2-2). Three replicate photographs were taken at all 

 REMOTS® stations. 



2.3 Sediment Sampling and Analysis 



Sediment samples were collected from the center of the reference areas (CLIS-REF, 

 4500E, and 2500W) with a 0.1 m 2 teflon-lined Van Veen grab sampler. Three samples 

 were collected for analysis at each reference area with each sample originating from a 

 separate grab. Subsamples from each grab were obtained using a 10 cm polycarbonate 

 plastic core liner (6.5 cm ID). A composite of the cores (0-10 cm) provided sufficient 

 sediment to fill precleaned 250 ml glass jars for chemical analyses (metals and PAHs). 

 Sediments for grain size and total organic carbon (TOC) were placed in plastic bags. 

 Samples were kept cold (approximately 4°C) and delivered to the NED laboratory. 

 Triplicate samples for each reference area were analyzed for TOC, PAHs, cadmium (Cd), 

 lead (Pb), and zinc (Zn). Grain size analyses were not run in triplicate, but on a composite 

 sample for each reference area at the NED laboratory. 



2.3.1 Grain Size Analysis 



American Society for Testing and Materials (ASTM) Method D422 was used for 

 grain size analysis (Table 2-1). Grain sizes were classified using the Wentworth 

 classification (phi scale) of grain size that assigns gravel phi values between -2 and -1, sand 

 between -1 and +4 inclusive, silts between 4 and 8 inclusive, and clays greater than 8. 

 Before initiating the analysis, a subsample (approximately 5-20 gm) was taken to determine 

 % total solids (% dry weight) and to allow for correction of percent moisture. Samples were 

 separated by a sieve analysis into size fractions greater than 62.5 fim (<4 phi), sand and 

 gravel, and less than or equal to 62.5 /xm (>4) silt and clay. Mechanically dry-sieving the 

 sediment through a graded series of screens subdivided the gravel-sand fraction. The wet- 

 sieved and dry-sieved fractions less than 62.5 /xm were combined for each sample. A pipet 

 technique that infers size by the settling rates of particles through a column of fresh water 

 subdivided the silt-clay fraction. 



2.3.2 Total Organic Carbon 



Total organic carbon, a measurement of organic matter (both labile and refractory) in 

 sediments, was measured using U.S. Environmental Protection Agency (EPA) Method 9060. 

 The analyzer converted organic carbon in the samples to carbon dioxide (C0 2 ). An infrared 

 detector measured the carbon dioxide. The amount of C0 2 is directly proportional to the 

 concentration of carbonaceous material in the sample. Inorganic forms of carbon (carbonate 

 and bicarbonate) are subtracted from the reported total organic carbon value. 



Monitoring Cruise at the Central Long Island Sound Disposal Site, June 1991 



