title: It is time to develop ecological thresholds of toxicological concern to assist environmental hazard assessment.
abstract: The threshold of toxicological concern (TTC) concept is well established for assessing human safety of food-contact substances and has been reapplied for a variety of endpoints, including carcinogenicity, teratogenicity, and reproductive toxicity. The TTC establishes an exposure level for chemicals below which no appreciable risk to human health or the environment is expected, based on a de minimis value for toxicity identified for many chemicals. Threshold of toxicological concern approaches have benefits for screening-level risk assessments, including the potential for rapid decision-making, fully utilizing existing knowledge, reasonable conservativeness for chemicals used in lower volumes (low production volume chemicals (e.g., < 1 t/yr), and reduction or elimination of unnecessary animal tests. Higher production volume chemicals (>1 t/yr) would in principle always require specific information because of the presumed higher exposure potential. The TTC approach has found particular favor in the assessment of chemicals used in cosmetics and personal care products, as well as other chemicals traditionally used in low volumes. Use of the TTC in environmental safety is just beginning, and initial attempts are being published. Key questions focus on hazard extrapolation of diverse taxa across trophic levels, importance of mode of action, and whether safe concentrations for ecosystems estimated from acute or chronic toxicity data are equally useful and in what contexts. The present study provides an overview of the theoretical basis for developing an ecological (eco)-TTC, with an initial exploration of chemical assessment and boundary conditions for use. An international collaboration under the International Life Sciences Institute Health and Environmental Sciences Institute has been established to address challenges related to developing and applying useful eco-TTC concepts.
authors.affiliation: Procter & Gamble, Cincinnati, Ohio, USA.
authors.forename: Scott E
authors.initials: SE
authors.lastname: Belanger
authors.affiliation: Aarhus University, Roskilde, Denmark.
authors.forename: Hans
authors.initials: H
authors.lastname: Sanderson
authors.affiliation: International Life Sciences Institute Health and Environmental Sciences Institute, Washington, DC, USA.
authors.forename: Michelle R
authors.initials: MR
authors.lastname: Embry
authors.affiliation: Dow Chemical Company, Midland, Michigan, USA.
authors.forename: Katie
authors.initials: K
authors.lastname: Coady
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Dick
authors.initials: D
authors.lastname: DeZwart
authors.affiliation: International Life Sciences Institute Health and Environmental Sciences Institute, Washington, DC, USA.
authors.forename: Brianna A
authors.initials: BA
authors.lastname: Farr
authors.affiliation: Unilever, Colworth Science Park, Sharnbrook, United Kingdom.
authors.forename: Steve
authors.initials: S
authors.lastname: Gutsell
authors.affiliation: European Commission, Joint Research Centre, Ispra, Italy.
authors.forename: Marlies
authors.initials: M
authors.lastname: Halder
authors.affiliation: US Environmental Protection Agency, Washington, DC, USA.
authors.forename: Robin
authors.initials: R
authors.lastname: Sternberg
authors.affiliation: Sanofi, Bridgewater, New Jersey, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Wilson
mesh_terms: D000818:Animals; D004463:Ecology / Q000379:methods*; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000633:toxicity*; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D015386:Hazardous Substances / Q000633:toxicity*; D006801:Humans; D018570:Risk Assessment
chemical_list: D004785:Environmental Pollutants; D015386:Hazardous Substances
keywords: Animal alternatives; Risk assessment; Threshold of toxicological concern (TTC)