47 



physical and chemical "mosaic". In ambient sediments, the contaminant-laden particles settle 

 to the bottom from a relatively uniform suspension and are subsequently mixed into the 

 sediment column. This contributes to a lower between-sample variance in chemical and 

 physical properties. 



Data collected as part of the National Oceanic and Atmospheric Administration's 

 (NOAA) National Stams and Trends Program (NS&T) were compared with the WLIS data to 

 provide a frame of reference (Table 4-2). The NS&T Program has collected and analyzed 

 coastal and estuarine sediment data from 300 sites since 1984. Several sites in Long Island 

 Sound were sampled over the period of 1984-1989 (NOAA 1991) and compared to the WLIS 

 reference area data. Of the NS&T sites in Western Long Island Sound, all are nearshore 

 except for the Western Long Island station (WLI); (Figure 4-3). In general, the Throgs 

 Neck station (the farthest west station in Long Island Sound) and the Sheffield Island station, 

 located northwest of WLIS, had the highest PAH concentrations (Table 4-2). Hempstead and 

 Huntington Harbors on the north shore of Long Island, and the Mamaroneck station on the 

 southern coast of Connecticut had the lowest PAH concentrations. Since the WLI station had 

 intermediate PAH values and is located nearest to WLIS, it will be used as a primary 

 reference to the WLIS data. PAH data were normalized both to the fine-grained fraction and 

 to TOC for comparison purposes (Table 4-2). 



PAHs are organic trace contaminants in estuarine and marine environments and 

 consist of carbon and hydrogen arranged in the form of two or more fused benzene rings in 

 linear, angular, or cluster arrangements. They encompass a wide range of chemicals, with 

 the principal sources in esmaries including industrial and mimicipal wastewater effluents, oil 

 spills, combustion of fossil fuels, commercial and recreational boating activities, riverbome 

 influx, nonpoint source runoff of materials from terrestrial habitats, and in situ diagenesis of 

 organic matter in sediments. Petroleimi spillage and atmospheric deposition are regarded as 

 the major sources of PAHs in the aquatic environment (Kennish 1992). 



Low molecular weight PAHs (including naphthalenes, anthracenes, fluorenes, and 

 phenanthrenes) tend to be more soluble, more volatile, and acutely toxic to some organisms, 

 but are noncarcinogenic. LMW PAH compounds originate principally from relatively fresh, 

 unbumed petroleum (Kennish 1992). Higher molecular weight PAHs (containing 4 to 7 

 rings) are carcinogenic, mutagenic, or teratogenic to a wide variety of organisms, including 

 fish and other aquatic life (Keimish 1992, Pequegnat et al. 1990). These compounds are less 

 volatile and have longer residence times in the aquatic environment. They include 

 fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(a)pyrene, and 

 benzo(g,h,i)perylene. HMW PAH compounds are generally derived from fossil fuel 

 combustion (Kennish 1992). It is currently thought that these pyrogenic PAHs are more 

 tightly bound to the particles than petroleum source PAHs (McGroddy et al. 1992). 



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



