Toxicity identification evaluations (TIEs) apply physico-chemical manipulations in conjunction with analytical tools to identify causes of toxicity in water and sediment samples. Depending on the biological receptor of concern, such studies may be performed with fish, invertebrates, aquatic plants or algae. Data from these studies have direct relevance to risk assessments, source identification, and design of effective treatment and remediation strategies.

Nautilus is a leading practitioner in the field of TIEs; our staff have developed a number of innovative methods that simplify the traditional TIE approach and provide more direct, cost-effective pathways through the identification process. In addition, Nautilus is at the forefront of determining cause(s) of toxicity in sediment quality investigations, and maintains close connections with analytical laboratories that provide unique capabilities in terms of identifying unknown toxicants at low concentrations. Finally, multiple independent lines of evidence and statistical verification are used in the TIE process to ensure rigorous conclusions with respect to the cause of toxicity.

While most TIEs involve a single cause of toxicity, Nautilus has unique capabilities related to identification of toxicants in complex samples in which multiple contaminants may contribute to toxicity, or where water chemistry conditions may alter toxicity (i.e., matrix effects). Moreover, we have specific experience with a wide range of contaminants, including ammonia, nitrite, sulfide, metals, pesticides, disinfectants, industrial chemicals and polymers, surfactants, petroleum hydrocarbons, ions and ion imbalances, and emerging chemicals of concern.

In addition to having detailed understanding of the chemical and toxicological properties of a wide range of potential toxicants, it is also important to have a working knowledge of different sample properties in order to properly implement a TIE and interpret the findings. In this regard, Nautilus has successfully performed TIEs on a wide variety of samples, including municipal and industrial wastewaters (e.g., sewage treatment plants, oil production and refining facilities, pulp and paper mills, sawmills, coal and metal mines), geothermal, agricultural and stormwater discharges, and contaminated sites (i.e., groundwater, and marine and freshwater sediments).