NIST standard reference materials (SRMs) for polychlorinated biphenyl (PCB) determinations and their applicability to toxaphene measurements

In the past five years the National Institute of Standards and Technology (NIST) has developed several Standard Reference Materials (SRMs) to assist in the validation of measurements of polychlorinated biphenyl (PCB) congeners and chlorinated pesticides in environmental samples. The following natural matrix SRMs have been issued: SRM 1588, Organics in Cod Liver Oil; SRM 1939, PCB Congeners in River Sediment; SRM 1941, Organics in Marine Sediment; SRM 1974, Organics in Mussel Tissue (Mytilus edulis); and SRM 1945, Whale Blubber. All of these SRMs have been analyzed for selected PCB congeners and chlorinated pesticides, and three of these materials (SRMs 1939, 1941, and 1974) have also been analyzed for polycyclic aromatic hydrocarbons (PAHs). In 1982, SRM 1649, Urban Dust/Organics, was issued with certified concentrations for selected PAHs. Recently, SRM 1649 has been analyzed for selected PCB congeners and chlorinated pesticides. Toxaphene measurements have not been made at NIST for these SRMs; however, these SRMs represent the environmental matrices that are typically analyzed for toxaphene. Recommended values for toxaphene concentrations could be established on any of these materials through interlaboratory comparison exercises involving laboratories experienced in making toxaphene measurements. In this paper we describe these SRMs and discuss their suitability as potential reference materials for toxaphene measurements.