Stable Chlorine Isotopic Compositions of Aroclors and Aroclor-Contaminated Sediments

Abstract

An exploratory investigation was conducted to evaluate if stable chlorine isotopic ratios of polychlorinated biphenyls (PCBs) could be useful in studying the processes that determine their transport and fate in the environment. First, we determined the variability of δ37Cl in the source materials for PCBs. Second, we determined if the δ37Cl values of contaminated environmental samples fell outside the range in source variability. The isotopic variability among the source materials (Aroclors) was rather small; δ37Cl values ranged from −3.37 to −2.11‰ (mean and standard deviation, −2.78 ± 0.39‰, n = 12). There was no correlation between the δ37Cl values and percentages of chlorine in the mixtures. We also found very similar values in several Clophen mixtures and one Phenoclor. The δ37Cl values in the total PCBs isolated from Aroclor-contaminated sediments from the Hudson River, New Bedford Harbor, and Turtle River Estuary ranged from −4.54 to −2.25% (n = 19). While most of the δ37Cl values were within 2 sta...