Funding Program: Contaminant Biology

Statement of Problem: With the increasing interest in the application of passive sampling technologies to the environmental monitoring of emerging contaminants, there is a need for the determination of data on the uptake kinetics of these chemicals into the samplers. Knowledge of uptake rates will allow the estimation of the time-weighted average ambient water concentration of sequestered chemicals. A significant amount of data exists for traditional hydrophobic contaminants (i.e., PAHs, PCBs, organochlorine pesticides [OCs]), however, there is a lack of information regarding the emerging contaminants which are currently receiving world-wide attention. Two types of passive samplers will be used in this study. These samplers are described below. Semipermeable membrane devices (SPMDs) consist of a layflat polyethylene membrane tube containing a neutral lipid (triolein). They are designed to mimic key aspects of the bioconcentration process, which results in elevated contaminant concentrations is organism tissues after exposure to trace hydrophobic organic contaminants in aquatic environments. Sampling of compounds with moderate to high octanol to water partition coefficients (Kows) is integrative (i.e., extracted residues are constantly accumulated without significant losses back into the environment) and analyte concentrations are reported as time weighted average (TWA) values. Like an SPMD, the polar organic chemical integrative sampler (POCIS) is designed to mimic key aspects of the bioconcentration process and an organism¿s exposure to hydrophilic organic contaminants. The POCIS consists of a solid phase sorbent or mixture of sorbents contained between two sheets of a microporous polyethersulfone membrane. Sampling of compounds with low to moderate Kows is integrative and analyte concentrations are reported as TWA values.
 
Objectives: SPMDs and POCIS will be exposed in controlled flow-through chambers to water impacted by treated wastewater effluents (test) and water with little to no influence (reference) from effluents. Chemical concentrations in the water will be monitored at days 0, 7, 14, 21, and 28. Passive samplers will be processed and analyzed at days 7, 14, 21, and 28. Comparison of the chemical concentrations in the passive samplers to the measured water concentration will allow for the determination of the uptake rate of the chemicals.