Effluent Toxicity Reduction
 Whole effluent toxicity (WET) testing, which uses test organisms to directly measure adverse effects of effluents, is an important component of NPDES permitting programs. When toxicity is identified during WET testing, a toxicity reduction evaluation (TRE) may be called for. TREs help to pinpoint the sources of toxicity and identify causative agents of effluent toxicity. They may also be used to evaluate the effectiveness of toxicity control options and confirm reductions in effluent toxicity.
In continuous operations since 1978, PBS&J’s environmental toxicology laboratory provides clients with timely, high-quality analytical services to support TRE needs from its 8,500-square-foot, state-of-the-art facility in Houston, Texas. PBS&J offers a full range of TRE services for municipal and industrial clients with either marine or freshwater receiving streams, including:
- Acquisition of toxicity information and data
- Facility performance evaluations
- Toxicity identification evaluations
- Toxicity source evaluation
- Toxicity control evaluations
 Toxicity Identification Evaluations
TIEs are a three-phased approach that must be conducted following established EPA procedures. PBS&J offers clients a proven resource for toxicity identification evaluations (TIEs) with experienced professionals that use procedures developed by the EPA to characterize and identify causative toxicants.
Phase I: Toxicity Characterization
A Phase I TIE is a logical, step-wise procedure for determining the classes of compounds responsible for the effluent toxicity. Phase I procedures are based on simple physical separation techniques, or the sorption or solubility properties of causative toxicants. Treated effluents are used in bioassays to determine if the treatment is effective in reducing toxicity.
Phase II: Specific Toxicant Identification
Phase II of the TIE is designed to allow identification of specific toxicants from the classes of compounds discovered in Phase I, or further delineation of other factors associated with the effluent that are causing toxicity.
Phase III: Toxicity Confirmation
Phase III of the TIE is designed to confirm that the compounds or problems identified in Phase II are the actual toxicants / problems. The method selected for this phase is dependant on the toxicant identity.
 Sediment Toxicity Identification
Sediments are a source of contamination within a watershed when the toxic compounds they contain are accumulated by fish and bottom-dwelling organisms and transferred up the food chain. EPA has developed a Contaminated Sediment Management Strategy that addresses this concern and will be tracking the activities of its program offices as they implement the strategy.
PBS&J has unique experience performing sediment TIEs through our activities associated with total maximum daily load (TMDL) studies. Our toxicologists, chemists, and environmental engineers investigate and identify the causes and sources of toxicity and provide cost-effective solutions for compliance with federal and state regulatory requirements.
- Sampling plan/data quality objectives design
- Sample collection
- Biological and/or chemical analysis of contaminated sediments
- Whole sediment and/or pore water TIEs
- Benthic community/habitat quality assessment
- Data evaluation
- Sediment quality triad assessment
- Dredged material disposal option analysis
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