Cost-effective in situ technologies may be able to strengthen causal relationships between chemicals and adverse health effects. Some previously developed methods used to establish stressor-causality linkages, such as the U.S. Environmental Protection Agency laboratory toxicity identification evaluation (TIE) method, may be confounded by excessive sample manipulations and temporal limitations. In contrast, the in situ TIE (iTIE) protocol is a biological fractionation protocol where water from an impacted site is differentially fractionated through an array of diagnostic resins and test organisms are directly exposed. This project prototyped and evaluated the use of an iTIE system (iTIES) in two phases.

 The objective of Phase I was to develop a prototype that linked chemical exposures to effects, allowing for cost-effective, realistic monitoring to support remediation decisions. Results are available in the Phase I Final Report. The objective of Phase II was to further optimize the iTIE prototype to expand its applications in a user-friendly design. Results are available in the Phase II Final Report.

The iTIE technology is a biological-chemical fractionation system that systematically identifies health effects. The iTIE system was created to separate co-occurring chemicals frequently linked to adverse biological effects. The system has multiple applications and can be used to assess potential impacts of a variety of chemicals and exposure pathways (i.e., overlying waters, groundwater-surface water interactions, effluents, or porewaters) to a range of test organisms. Chemical analyses of water and resins or other absorbents used from each iTIE unit can also be compared to endpoints (e.g., lethality) and in situ exposure biomarkers for an integrated, environmentally realistic assessment.

During Phase I, an iTIE prototype was developed. The iTIE prototype was more sensitive at detecting ambient toxicity than the traditional laboratory-based TIE and required fewer resources to conduct an experiment. 

During Phase II, the iTIE prototype was expanded into the comprehensive iTIES, which can separate a wide range of chemicals, including ammonia, heavy metals, organophosphate pesticides, per- and polyfluoroalkyl substances (PFAS), polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and other organic chemicals of varying polarities. Numerous organisms and biological endpoints are compatible with iTIE testing, including fish teratogenicity and enzymatic bioassays. Following optimization, the iTIES was successfully used in a variety of field settings, both marine and freshwater, to identify and rank chemicals driving effects at particular sites.

The iTIES may be an option for tiered risk assessments at sites. If health effects are detected, the iTIES may be used to identify which chemicals are present, to establish causal linkages between chemicals and health effects, and to rank chemicals causing stress. The successful execution of this research yielded data essential for the development of advanced technologies aimed at enhancing ongoing remediation efforts at PFAS-impacted sites, thereby providing crucial safeguards for warfighters and installation communities. (Project Completion - 2025)

Burton, G.A., E.C. Cervi, K. Meyer, A. Steigmeyer, E. Verhamme, J. Daley, M. Hudson, M. Colvin, and G. Rosen. 2020. A Novel In Situ Toxicity Identification Evaluation (iTIE) System for Determining which Chemicals Drive Impairments at Contaminated Sites. Environmental Toxicology and Chemistry, 39(9):1746-1754. doi.org/10.1002/etc.4799.  

Steigmeyer, A. J., J. Zhang, J. Daley, X. Zhanfg, and G. A. Burton, Jr. 2017. An In Situ Toxicity Identification and Evaluation Water Analysis System: Laboratory Validation. Environmental Toxicology and Chemistry, 36:1-8. doi.org/10.1002/etc.3696.