Chlorobiphenyls compositions

In the United States PCB preparations are marketed under the trade name Aroclor and consist of complex mixtures of chlorobi-phenyls. Table I gives the chlorobiphenyl composition of some... 

The composition of the chlorobiphenyl mixtures present In the surface sediment, particulate matter In the water column, filtrate from water column samples, and mussels reflect a combination of Aroclor 1242 and 1254 mixtures of chlorobiphenyls although there are distinct differences In each sample type. The chlorobiphenyl composition of water column samples (gas chromatograms not shown) resembles that of the mussels and surface sediments, although further measurements of a larger set of samples may reveal small but significant differences In composition. 

Examination of the gas chromatograms of PCBs In the samples of lobster and crab reveals the marked contrast In composition of PCBs In these types of biota samples and the composition of PCBs In water, sediment, bivalves and Aroclor mixtures. For example, the chlorobiphenyl composition of the lobsters are dominated by lUPAC chlorobiphenyl (CB) numbers 118, 153 and 138 while numbers 118 and 153 dominate the composition In the crab (Figure 2). Several more chlorobiphenyls, e.g. 28, 52, 44, 70, 95, 101, 110, are present In the mussel and sediment samples In addition to 118, 153 and 138 (Figure 2). PCBs In flesh of flounder species (L. maculata and P. amerlcanus) were Intermediate In composition between the lobsters and the mussels based upon examination of the gas chromatograms (not shown), I.e. 118, 153 and 138 predominate but not as much as In the lobsters. The possible reasons for these differences will be discussed below. 

We report here on the distributions of several chlorobiphenyls In samples of water, sediment and biota of the Acushnet River Estuary - New Bedford Harbor, Buzzards Bay, Massachusetts, U.S.A. Our general objective Is to gain Information of generic utility In addition to providing specific data and Interpretations of assistance to remedial action at this Superfund site. Our specific objectives In this paper are to 1) document the composition of Individual chlorobiphenyls In biota normally harvested by commercial and recreational fishermen and discuss factors which could lead to the observed distributions and potential Implications for public health standards for PCBs In fish and 11) to Investigate, In a preliminary manner, the adherence of bloconcentratlon of PCBs to predictions based on equilibrium assumptions and octanol/water (Kg ) partition coefficients (, 22). 

The visual inspection of gas chromatograms (Figures 2-4) provides only a qualitative impression of the relative differences in composition of PCBs in the biota and their habitat. Therefore, we have calculated a parameter to provide a more quantitative means for evaluating the differences in composition. We have chosen a chlorobiphenyl, lUPAC No. 153, which is present in appreciable quantities in the industrial mixture of Aroclor 1254 and was identified as one of the major components in the samples of biota from the study area, and calculated the following ratio ... 

The approximate weight percent of chlorobiphenyls in some commercial Aroclors is summarized in Table 4-4, and the congener composition of Aroclors is shown in Table 4-5. The congener composition of commercial PCBs may vary from lot to lot even in products from the same manufacturer. In addition, no two descriptions of commercial PCB mixtures, even from the same lot or a manufactured product, are identical because of slight differences in the conditions of the chlorination process or the use of different analysis procedures. For example, a late production Aroclor 1254 lot (Aroclor 1254 Late ), with greatly... 

Hansen LG, Green D, Cochran J, et al. Chlorobiphenyl (PCB) composition of extracts of subsurface soil, superficial dust and air from a contaminated landfill. F J Anal Chem 357 442-448. 

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