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Consulting and Environmental Studies

Environmental Systems Service, Ltd. (ESS) provides many aquatic programs to both monitor and manage natural resources. From basic groundwater monitoring to biological studies of lakes and streams, ESS is able to assist with your program development.   With a highly skilled staff of environmental scientists, biologists, field sample technicians, and in-house laboratory, clients can be confident that their environmental issues will be adequately addressed.

Services provided include:
  • Lake Management Studies
  • Stream Surveys
  • Wetlands Delineation and Mitigation
  • Toxicity Reduction Evaluations
  • Trace Metal Water Effect Ratio (WER) Studies
  • Metals' Translator Evaluation
  • Permitting

Recognizing the need to protect and preserved the natural environment, while also moving forward with technology, ESS is able to assess and provide solutions for a range of aquatic programs. Each assessment is tailored to meet the specific client requests and any governing requirements. With tremendous experience, we are able to provide consulting expertise.

Client list includes federal and state government agencies, municipalities, Fortune 100 industrial companies, school systems, commercial and residential clients.

Trace Metal Water-Effect Ratio Studies

Many VPDES permits for wastewater treatment facilities contain very stringent effluent limits for Copper and/or Zinc.  These imposed limits were inserted in discharge permits by the Virginia Department of Environmental Quality in response to EPA criteria designed to protect aquatic species from metals’ toxicity.  Permit limits are typically established using EPA toxicity criteria derived from toxicity testing using laboratory water rather than actual stream or final plant effluent.  In many cases the actual toxicity exerted by the plant effluent on the receiving stream is significantly less than that expressed by the EPA laboratory criteria.  EPA has developed a methodology designed to determine and compare actual site water toxicity to EPA criteria.  Water Effects Ratio studies provide a means of evaluating actual discharge toxicity as compared to EPA established criteria.  A study plan for each case must be developed and submitted to DEQ and EPA for approval prior to beginning the study.  A series of samples are collected using both receiving stream and plant effluent, and side by side toxicity tests are used to compare toxicity of laboratory water with actual site water.  Depending on results of the study it may be possible to receive a significant adjustment of actual effluent limits, especially for Copper.


ESS conducts trace metal water-effect ratio (WER) studies, consistent with State and U.S. EPA guidance to adjust metals criteria, based on site-specific water quality characteristics, as allowed under DEQ and EPA protocol.  ESS provides work plan preparation and negotiation with state regulators, sample collection and transport, data analysis, final WER determination, and report preparation. Finally, ESS staff work closely with state regulators to modify VPDES permit limits based on the site-adjusted metals criteria determined from the WER study.



Metals’ Translator Evaluation


Discharge permit limits imposed by EPA are based on total recoverable metal concentration.  In some cases, the actual toxicity exerted by the metal of question is less than that demonstrated in EPA laboratory results used for permit limit determination.  This is especially true if the plant effluent contains total organic carbon.  Organic carbon tends to absorb a fraction of the metal, thus reducing its toxic impact on the receiving stream.  This impact can be measured and evaluated by conducting a metals translator study. Metals translator studies are designed to evaluate the actual toxicity of specific metals using both total and dissolved fractions.  Samples of plant effluent are collected using clean technique and a portion of each sample is filtered in the field using EPA protocol for ultra low trace metal sampling and analyses procedures.  Samples are delivered to the laboratory under strict ESS sample handling protocol and analyzed for both total and dissolved metal content.  A comparison of total vs. dissolved concentrations is conducted.  Based on the results of the comparison, it may be possible to receive a permit modification allowing for less stringent total metals limits using the dissolved metal fraction for determination of toxicity.  ESS will structure a complete metals translator evaluation package including study plan development, field sampling using clean technique, laboratory analyses, data review, and preparation of a final report for submittal to regulatory agencies.  If the study is successful in producing  a change in metals concentration contained in the VPDES permit, ESS will work with the client and regulatory agencies to modify the discharge permit to take advantage of the relaxed limits.




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Corporate Office    

ESS, Ltd.    
218 North Main Street    
Culpeper, VA 22701    

toll free 1-800-541-2116    
office 1-540-825-6660    
fax 1-540-825-4961    

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Environmental Systems Services, Ltd. (ESS) - Culpeper - Virginia
Corporate Office: 1-800-541-2116 -

ESS is a member of the Culpeper Chamber of Commerce

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