Treated sewage, stormwater runoff and industrial waste are sources of chemical contamination in coastal sediments. Although studies of sedimentary chemistry have resulted in stringent laws on discharging toxic chemicals into the sea, the more toxic chemicals can have lasting effects on the environment.

Polychlorinated biphenyls (PCBs) are an important class of industrial pollutants that areubiquitous in the marine and freshwater environments (NAS, 1979). Although the “planar” or“non-ortho” PCB congeners are present in much lower concentrations than other PCBcongeners, they can be responsible for much of the dioxin-like (TCDD) toxicity in the marineecosystem. Further, their environmental fate may be different from other PCBs. Theirdetermination is, therefore, crucial for assessment of contaminant status of environmentalcompartments. Mono-ortho PCBs and polychlorinated naphthalenes (PCN) although less potent,also exhibit TCDD-like toxicity. Yet, only total PCBs are usually reported and the levels of non-and mono-ortho PCBs relative to total PCBs have rarely been studied and data on PCN areuncommon in oceanic samples (Jarnberg et al., 1993). Among the known sources, municipalwaste dischargers could be a significant contributor of these synthetic compounds to the ocean(i.e., Venkatesan, 1998; Zeng and Venkatesan, 1999).