Thresholds of toxicological concern for endocrine active substances in the aquatic environment

The threshold of toxicological concern (TTC) concept proposes that an exposure threshold value can be derived for chemicals, below which no significant risk to human health or the environment is expected. This concept goes further than setting acceptable exposure levels for individual chemicals, because it attempts to set a de minimis value for chemicals, including those of unknown toxicity, by taking the chemical's structure or mode of action (MOA) into consideration. This study examines the use of the TTC concern concept for endocrine active substances (EAS) with an estrogenic MOA. A case study formed the basis for a workshop of regulatory, industry and academic scientists held to discuss the use of the TTC in aquatic environmental risk assessment. The feasibility and acceptability, general advantages and disadvantages, and the specific issues that need to be considered when applying the TTC concept for EAS in risk assessment were addressed. Issues surrounding the statistical approaches used to derive TTCs were also discussed. This study presents discussion points and consensus findings of the workshop.

[1]  Martin Scholze,et al.  Modeling effects of mixtures of endocrine disrupting chemicals at the river catchment scale. , 2006, Environmental science & technology.

[2]  Ioanna Katsiadaki,et al.  Use of the Three-Spined Stickleback (Gasterosteus aculeatus) As a Sensitive in Vivo Test for Detection of Environmental Antiandrogens , 2005, Environmental health perspectives.

[3]  R Kroes,et al.  The threshold of toxicological concern concept in risk assessment. , 2005, Toxicological sciences : an official journal of the Society of Toxicology.

[4]  Weida Tong,et al.  Prediction of estrogen receptor binding for 58,000 chemicals using an integrated system of a tree-based model with structural alerts. , 2001, Environmental health perspectives.

[5]  Mark Crane,et al.  Evaluation of probabilistic risk assessment of pesticides in the UK: chlorpyrifos use on top fruit. , 2003, Pest management science.

[6]  G. Ankley,et al.  Screening and Testing for Endocrine Disruption in Fish—Biomarkers As “Signposts,” Not “Traffic Lights,” in Risk Assessment , 2005, Environmental health perspectives.

[7]  Scott D. Kahn,et al.  Current Status of Methods for Defining the Applicability Domain of (Quantitative) Structure-Activity Relationships , 2005, Alternatives to laboratory animals : ATLA.

[8]  S Coecke,et al.  The use of metabolising systems for in vitro testing of endocrine disruptors. , 2008, Current drug metabolism.

[9]  Ioanna Katsiadaki,et al.  Three-spined stickleback: an emerging model in environmental endocrine disruption. , 2007, Environmental sciences : an international journal of environmental physiology and toxicology.

[10]  Arantzazu Urzelai,et al.  Minimum data required for deriving soil quality criteria from invertebrate ecotoxicity experiments , 1999 .

[11]  Birgit Sokull-Klüttgen.  Screening of the European Union New Chemicals Database concerning an aquatic exposure threshold of no concern. , 2007, Environmental toxicology and chemistry.

[12]  Watze de Wolf,et al.  Mode of action and aquatic exposure thresholds of no concern , 2005, Environmental toxicology and chemistry.

[13]  J R Wheeler,et al.  Species sensitivity distributions: data and model choice. , 2002, Marine pollution bulletin.

[14]  J. Hermens,et al.  Classifying environmental pollutants , 1992 .

[15]  G. Patlewicz,et al.  An evaluation of the implementation of the Cramer classification scheme in the Toxtree software , 2008, SAR and QSAR in environmental research.

[16]  C. A. Harris,et al.  Accurate Prediction of the Response of Freshwater Fish to a Mixture of Estrogenic Chemicals , 2005, Environmental health perspectives.

[17]  C. A. Harris,et al.  Evidence of estrogenic mixture effects on the reproductive performance of fish. , 2007, Environmental science & technology.