Whole Effluent Toxicity (WET)

GBMc & Associates provides expertise to industrial and municipal clients related to their NPDES required WET testing application. We have extensive experience in issues related to the implementation both routine WET testing and the development and implementation of TREs and TIEs in compliance with NPDES mandated toxicity testing.  Ever increasing focus on WET testing as a method to measure permit compliance requires increased attention to routine monitoring of WET test results to document both test success and test failures. EPA and State application of reasonable potential determination requires ever vigilant attention to both lethal and non-lethal WET test performance.  GBMc individualizes EPA/state methods to cost effectively address WET testing and TRE issues applying a tiered approach to facility WET test compliance.  

Experience and Capabilities

  • Completed TRE/TIE for numerous industrial facilities on both effluent and storm water runoff types of applications including mining and aluminum processing, poultry, agri-chemical production, pesticide/herbicide formulation, superfund remediation, metal plating and fabrication, wood products, municipal wastewater treatment (POTW), and specialty chemical production.
  • Completed review and evaluation of hundreds of toxicity test results for adherence to required protocols and appropriate interpretation by analytical laboratories and regulatory agencies.
  • Critically reviewed application of toxicity testing data in toxicological reports in litigation support for facilities in Arkansas, Texas and Louisiana.
  • Assessed potential aquatic toxicity of multiple pesticides and pesticide intermediates.  Compiled a research database of toxicity endpoints for each chemical derivative.
  • Completed numerous water effect ration (WER) studies for industrial and municipal wastewater plants.  Have evaluated water effects of copper, lead and zinc and successfully changed WQS to improve permit limits. 
  • Permit review and support to numerous industrial facilities and POTW’s in permit language development and support for permit appeal.
  • Completed numerous side-by-side effluent and receiving stream toxicity tests to document absence of instream effects despite effluent toxicity (WER application).
  • Developed and completed laboratory audits of toxicity testing facilities to evaluate adherence to EPA methods.
  • Developed documentation to eliminate /or reduce NPDES required WET testing based on historical results.


GBMc Contact Greg Phillips