December 2008
Microbial Exposure Assessment in the Lower Passaic River
Our Challenge
- ChemRisk evaluated the risk of pathogen-related disease associated with discharges from combined sewer overflow (CSO) systems
- During precipitation events, CSO systems often release untreated human sewage into surface water bodies to avoid overloading wastewater treatment plants
Our Approach
- We collected and analyzed water samples from six different locations along the Passaic River
- Analyzed for fecal coliforms, total coliforms, fecal Streptococcus, fecal Enterococcus, Giardia lamblia, Cryptospordium parvum, and several viruses
- Data used to conduct a quantitative microbial risk assessment
Our 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