Chemrisk.Com Area of Expertise

Persistent chemicals are substances that do not degrade in the environment, may bioaccumulate through the food web, and have the potential to cause adverse effects to human health and the environment. The majority of these chemicals have low water solubilities, tend to partition to organic matter in soil and sediment, and tend to partition to lipids in humans and biota.

Because these chemicals persist in the environment and many of them bioaccumulate through the terrestrial and aquatic food webs, the key risk assessment and exposure assessment issues associated with these chemicals are:

The movement of these chemicals from the primary impacted source (soil, sediment, or facility emissions) through the food web;
the need to understand indirect exposure pathways such as consumption of dairy products, eggs, meat, and poultry from impacted agricultural areas or consumption of fish and shellfish from impacted water bodies;
the potential for exposures to indoor dust for those chemicals that are found in consumer products;
the impact of the long environmental and biological half-lives in relation to their exposure potential and toxicity, and;
the ability to understand human exposures to these chemical using biomonitoring data.

ChemRisk^® has extensive experience with many persistent chemicals, including: polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs), polyfluorocarbon chemicals (PFCs), and various pesticides.

We have performed evaluations for over twenty sites where persistent chemicals have been chemicals of interest, have over 100 combined years of professional experience with these chemicals, and have published over 100 published abstracts, peer-review publications, and book chapters related to persistent chemicals. Several of our professionals have served as consulting or testifying experts for litigation involving these chemicals as well as testifying before different state and federal government panels regarding the human health and ecological risks associated with these chemicals.

Some of our relevant project experience in this area includes:

Comparative analysis of risks associated with PCDD/Fs and PCBs in fish caught and consumed from the Passaic River in New Jersey
Development of refined methodologies for derivation of the PCDD/F and PCB toxic equivalent factors
Evaluation of PCDD/F levels in serum of workers at a magnesium facility
Historical exposure reconstruction of PFOA emissions from a fluoropolymer manufacturing facility

ChemRisk^® Publications

Connor K.T., M. Eversen, S.H. Su, and B.L. Finley. 2005. Quantitation of polychlorinated biphenyls in fish for human cancer risk assessment: a comparative case study. Environ Toxicol Chem. 24(1):17-24.

Ferriby, L.L., J.S. Knutsen, M. Harris, K.M. Unice, P. Scott, P. Nony, L.C. Haws, and D.J. Paustenbach. 2007. Evaluation of PCDD/F and dioxin-like PCB serum concentration data from the 2001-2002 National Health and Nutrition Examination Survey of the United States Population. J Exp Sci Env Epidemiol. 17:358-371.

Finley, B.L., K.T. Connor, and P.K. Scott. 2003. The use of toxic equivalency factor distributions in probabilistic risk assessments for dioxins, furans, and PCBs. J Toxicol Environ Health A. 66(6):533-550.

Gaffney, S.H., F.C. Curriero, P.T. Strickland, G.E. Glass, K. Helzlsouer, and P.N. Breysse. 2005. Influence of geographic location in modeling blood pesticide levels in a community surrounding an EPA Superfund site. Environmental Health Perspectives. 113(12):1712-6.

Paustenbach, D.J., K. Fehling, P. Scott, M. Harris and B.D. Kerger. 2006. Identifying soil cleanup criteria for dioxins in urban residential soils: How have 20 years of research and risk assessment experience affected the analysis? J Toxicol Environ Health. B Crit Rev. 9(2):87-145.

Paustenbach, D.J., J.M. Panko, P.K. Scott and K. M. Unice. 2006. A methodology for estimating human exposure to perfluorooctanoic acid (PFOA): A retrospective exposure assessment of a community (1951-2003). J Toxicol Environ Health. 70:28-57.

Staskal D.F., Scott L.L., Haws L.C., Luksemburg W.J., Birnbaum L.S., Urban J.D., Williams E.S., Paustenbach D.J., Harris M.A. 2008. Assessment of polybrominated diphenyl ether exposures and health risks associated with consumption of southern Mississippi catfish. Environ Sci Technol. 42(17):6755-61.

For Additional information, please contact Paul Scott at pscott@chemrisk.com; (412) 281-6900, ext 1021