Quantitative Microbial Risk Assessment
- Challenge: Cardno ChemRisk evaluated the risk of pathogen-related disease associated with discharges from Combined Sewer Overflow (CSO) systems for the lower Passaic River in New Jersey. These risks were assessed and compared to the risks associated with exposure to contaminated sediment, fish and shellfish in the same area of the Passaic River.
- Approach: Cardno ChemRisk collected and analyzed water samples from six locations along the Passaic River and analyzed them for fecal coliforms, total coliforms, fecal Streptococcus, fecal Enterococcus, Giardia lamblia, Cryptospordium parvum and several viruses. These data were used to conduct a quantitative microbial risk assessment.
- Findings: Nearly all pathogen concentrations exceeded health-based water quality criteria. Risk estimates for illness associated with transient exposure to Giardia-contaminated sediments exceeded 1 in 100. The risk of pathogen-related disease was much higher than the estimated theoretical cancer risk and noncancer hazard associated with chemical exposures.
- Value: This analysis helped the client put chemical risks in perspective for the U.S. EPA, the lead agency for the site.
- Donovan E., D.F. Staskal, K. Unice, J.D. Roberts, L.C. Haws, B. Finley and M. Harris. 2008. Risk of gastrointestinal disease associated with exposure to pathogens in the sediments of the Lower Passaic River. Appl Environ Microbiol. 74: 1004-1018
- Donovan E., K. Unice, J.D. Roberts, M. Harris and B. Finley. 2008. Risk of gastrointestinal disease associated with exposure to pathogens in the water of the Lower Passaic River. Appl Environ Microbiol. 74: 994-1003