Effluent bioassays, biomonitoring and Whole Effluent Toxicity(WET) testing are all terms used to describe testing a wastewater discharge with aquatic organisms to assess the discharge's toxicity.  Required biomonitoring under National Pollutant Discharge Elimination System (NPDES) permits may include freshwater, marine, or estuarine species.   

Northwestern Aquatic Sciences has conducted thousands of effluent toxicity tests since 1979.   Test organisms are cultured at our facility, purchased from commercial suppliers, or collected from wild populations, depending on the species, availability and test requirements.  As an extra QC measure, a reference toxicant test is run concurrently with every toxicity test set up.  Sample kits are provided to our clients for overnight shipment of samples to our laboratory.  These sample kits are coolers that include chain-of-custody forms, sample containers, ice packs, instructions, and return labels. 

WET tests are most frequently tested in accordance with the U.S.EPA (Environmental Protection Agency) methods listed below:

• EPA/600/4-90/027F  Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, Fourth Edition, August 1993.
  
• EPA/600/4-91/002  Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Water to Freshwater Organisms.  Third Edition, July 1994.
  
• EPA/600/4-91/003  Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine Organisms, Second Edition, July 1994.
  
• EPA/600/R-95/136  Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to West Coast Marine and Estuarine Organisms, August 1995.