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.

Revisiting bioaccumulation criteria for POPs and PBT assessments.

Scientists from academia, industry, and government reviewed current international regulations for the screening of commercial chemicals for bioaccumulation in the context of the current state of bioaccumulation science. On the basis of this review, several recommendations were proposed, including a scientific definition for "bioaccumulative substances," improved criteria for the characterization of bioaccumulative substances (including the trophic magnification factor and the biomagnification factor), novel methods for measuring and calculating bioaccumulation properties, and a framework for screening commercial chemicals for bioaccumulative substances. The proposed framework for bioaccumulation screening improves current practices by reducing miscategorization, making more effective use of available bioaccumulation data that currently cannot be considered, reducing the need for animal testing, providing simpler and cheaper test protocols for animal studies in case animal studies are necessary, making use of alternative testing strategies, including in vitro and in silico metabolic transformation assays, and providing a scientific foundation for bioaccumulation screening that can act to harmonize bioaccumulation screening among various jurisdictions.

Acute and chronic aquatic toxicity of ammonium perfluorooctanoate (APFO) to freshwater organisms.

Recent concerns have been raised concerning the widespread distribution of perfluorinated compounds in environmental matrices and biota. The compounds of interest include ammonium perfluorooctanoate (APFO, the ammonium salt of perfluorooctanoic acid, PFOA). APFO is used primarily as a processing aid in the production of fluoropolymers and fluoroelastomers.

Are PFCAs bioaccumulative? A critical review and comparison with regulatory criteria and persistent lipophilic compounds.

Perfluorinated acids, including perfluorinated carboxylates (PFCAs), and perfluorinated sulfonates (PFASs), are environmentally persistent and have been detected in a variety of wildlife across the globe. The most commonly detected PFAS, perfluorooctane sulfonate (PFOS), has been classified as a persistent and bioaccumulative substance. Similarities in chemical structure and environmental behavior of PFOS and the PFCAs that have been detected in wildlife have generated concerns about the bioaccumulation potential of PFCAs.

Animal use replacement, reduction, and refinement: development of an integrated testing strategy for bioconcentration of chemicals in fish.

When addressing the use of fish for the environmental safety of chemicals and effluents, there are many opportunities for applying the principles of the 3Rs: Reduce, Refine, and Replace. The current environmental regulatory testing strategy for bioconcentration and secondary poisoning has been reviewed, and alternative approaches that provide useful information are described. Several approaches can be used to reduce the number of fish used in the Organization for Economic Cooperation and Development (OECD) Test Guideline 305, including alternative in vivo test methods such as the dietary accumulation test and the static exposure approach.

Mode of action and aquatic exposure thresholds of no concern.

Threshold concepts of toxicological concern are based on the possibility of establishing an exposure threshold value for chemicals below which no significant risk is to be expected. The objective of the present study is to address environmental thresholds of no toxicological concern for freshwater systems (ETNCaq) for organic chemicals. We analyzed environmental toxicological databases (acute and chronic endpoints) and substance hazard assessments.

A rule-based screening environmental risk assessment tool derived from EUSES.

Within the context and scope of the forthcoming European Union chemical regulations (REACH), there is a need to be able to prioritise the chemicals for evaluation. Therefore, a simple, pragmatic and adequately conservative approach for the identification of substances of very low or no immediate concern at an early stage is presented. The fundamental principles and basic concepts are derived from the EU Technical Guidance Document and EUSES, and are translated into an easy-to-use rule-based system.

Removal of fragrance materials during U.S. and European wastewater treatment.

The concentrations and removals of 16 fragrance materials (EMs) were measured in 17 U.S. and European wastewater treatment plants between 1997 and 2000 and were compared to predicted values.