CONSULTING SERVICES
Toxicity Identification Evaluation / Toxicity Reduction Evaluation (TIE/TRE)
When standard toxicity testing identifies a sample as being "toxic", the first question is often "What is causing this toxicity?" A toxicity identification evaluation (TIE) is an organized progression through a number of published methods, to isolate and identify the toxicity causing agent.
Once the toxicity-causing agent is identified, toxicity reduction evaluation (TRE) addresses the "How can we resolve this toxicity?" question. TRE employs another set of recognized methods to determine the most efficient and effective method for reducing the toxic effect.
The three phases of the U.S. EPA developed TIE/TRE program are:
Phase 1) Toxicant Characterization - Tests that can tentatively categorize the toxicants as cationic metals, non-polar organics, oxidants, substances whose toxicity is pH dependent, etc. as well as development of physical/chemical characteristics of the toxicant such as filterability, degradability, volatility and solubility.
Once the toxicant has been isolated by the TIE/TRE program, an investigation can be completed to determine the internal source of the toxicant and the method to source control or enhance a water treatment system to reduce toxicant levels.
It is necessary to the success of a TIE/TRE program that the toxicity is frequently present in the effluent so that the toxicant(s) of concern can be characterized and subsequently identified and confirmed through repeat testing.
It has been our experience that, though the EPA has developed specific protocols for TIE/TRE investigations, most users of these protocols utilize them as a guide for evaluating toxicity problems. We approach the problem of effluent toxicity similar to how one would evaluate and solve any problem through the review, assessment and implementation of common sense investigative techniques.