USING PASSIVE SAMPLERS at Contaminated Sediment Superfund Sites A cost-effective and scientifically robust method to measure contaminant concentrations in aquatic systems WHAT DO PASSIVE SAMPLERS DO? • Measure freely dissolved concentrations (i.e., bioavailable) of contaminants in aquatic systems • Collect time integrated, average samples that account for variations in concentrations • May serve as surrogate for organism bioaccumulation • Applications in water column and sediment interstitial waters LOW DENSITY POLYETHYLENE (LDPE) JR Mussels Water Column Passive Samplers Benthos SOLID PHASE MICROEXTRACTION (SPME) Sediment PCBs PAHs DDT Deployment of Passive Samplers in Aquatic Systems Wildlife WHY USE PASSIVE SAMPLERS? • Improve accuracy and precision of measuring freely dissolved concentrations • Assess bioavailability and risk to benthic organisms • Reduce uncertainty in eco-risk assessment • Delineate Exposure Units, Decisions Units, or Sediment Management Units • Assess remedy effectiveness and monitor risk reduction • Target hydrophobic organic contaminants, such as PCBs, PAHs, dioxins, furans, and chlorinated pesticides 189672 TYPES OF PASSIVE SAMPLERS POLYOXYMETHYLENE (POM) United States MkKM Environmental Protection OFFICE OF SUPERFUND REMEDIATION AND TECHNOLOGY INNOVATION Agency ------- HOW DO PASSIVE SAMPLERS WORK? Samplers are cleaned and sealed in clean containers until deployment. DEPLOY Contaminants partition into polymer until equilibrium with the environmental media is achieved. Samplers are recovered, cleaned, and submitted to laboratory for analysis. ANALYZE Laboratory conducts chemical analysis of sampler. Dissolved contaminant concentrations in adjacent media are calculated. CONTAMINANT CONCENTRATIONS IN PASSIVE SAMPLER OVER TIME Actual concentration in media Concentration measured by passive sampler (B) UPTAKE Resuspension Event Time-Averaged Measurement (A) DEPLOYMENT (C) EQUILIBRIUM XbASM rfi- Time United States Environmental Protection i Agency Learn more at: Webinar: http://bit.ly/1BxsQKH SAMS: http://1 .usa.gov/1 E6j4gR OSRTI Contaminated Sediments Site: http://1 .usa.gov/1 InwNUO ------- |