New Developments in Standard Reference Materials (SRMs) for Environmental Forensics

Abstract

For nearly three decades the National Institute of Standards and Technology (Gaithersburg, MD) has been involved in the development of Standard Reference Materials (SRMs) for the determination of organic contaminants in environmental matrices. Classes of organic contaminants characterized in these materials include polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated pesticides, and most recently, brominated flame retardants (polybrominated diphenyl ethers [PBDEs]). Environmental matrices include fossil fuels, air and diesel particulate matter, house dust, coal tar, sediment, mussel and fish tissue, fish oil, and whale blubber. Recent SRM developments and activities have led to a number of environmental SRMs that are useful for assuring quality of analytical measurements in environmental forensics where source profiling of organic contaminants is often conducted in a range of environmental or biological matrices. Particle-related SRM developments include the issue of a new house dust material (SRM 2585 Organic Contaminants in House Dust), and the recertification of two SRMs: a diesel particulate matter material (SRM 1650b Diesel Particulate Matter) for certified and reference values for 97 PAHs and nitro-PAHs and a river sediment (SRM 1939b PCBs in River Sediment A) for a greater number of PCB congener concentrations relative to its former certification in 1998 as well as for total PCBs. A coal tar SRM (SRM 1597a Complex Mixture of PAHs from Coal Tar) has also been reissued with an expanded range of values for PAHs (including methyl- and dimethyl-substituted PAHs, PAH isomers of molecular mass 302, and polycyclic aromatic sulfur heterocycles [PASH]). The latest biological SRM developments include the issue of a new fish tissue SRM (SRM 1947 Lake Michigan Fish Tissue) and the recertification of a cod liver oil (SRM 1588b Organics in Cod Liver Oil) and a human serum (SRM 1589b PCBs, Pesticides, PBDEs, and Dioxins/Furans in Human Serum). SRM 1588b has values assigned for 124 constituents, and SRM 1589b has values assigned for 88 constituents. An overview of these recent SRM activities is provided in this paper, and selected organic contaminant values in newly developed particulate-related and biological SRMs are presented. The usefulness of these materials for assuring quality in environmental forensic measurements is also discussed.