Assessment of bioconcentration and secondary poisoning of surfactants.

The relevance of the bioconcentration behaviour of surfactants for the secondary poisoning assessment and for the risk characterisation in the bird and mammalian food chain has been investigated. The approach used is described in the recently revised EU Technical Guidance Document for the Risk Assessment of Substances. The results demonstrate that, based on experimentally derived bioconcentration factors, environmental concentrations and effects in animals, there is a clear level of safety for both linear alkylbenzene sulphonate (LAS) and alcohol ethoxylates (AE), the most important surfactants by volume. To assess other surfactants used in detergents, a bioconcentration factor that would need to be attained for secondary poisoning to be of concern has been estimated from predicted environmental concentrations and known long-term effects data in animals. Based on the known structural similarity of these surfactants to LAS and AE and the ubiquitous nature of the enzymatic systems that are present in biotransformation processes in organisms, it is concluded that bioconcentration of these surfactants to these levels is highly unlikely. Therefore the potential for secondary poisoning effects of these surfactants is extremely low.

Ecological risk assessment of endocrine disruptors.

The European Centre for Ecotoxicology and Toxicology of Chemicals proposes a tiered approach for the ecological risk assessment of endocrine disruptors, integrating exposure and hazard (effects) characterization. Exposure assessment for endocrine disruptors should direct specific tests for wildlife species, placing hazard data into a risk assessment context. Supplementing the suite of mammalian screens now under Organization for Economic Cooperation and Development (OECD) validation, high priority should be given to developing a fish screening assay for detecting endocrine activity in oviparous species. Taking into account both exposure characterization and alerts from endocrine screening, higher tier tests are also a priority for defining adverse effects. We propose that in vivo mammalian and fish assays provide a comprehensive screening battery for diverse hormonal functions (including androgen, estrogen, and thyroid hormone), whereas Amphibia should be considered at higher tiers if there are exposure concerns. Higher tier endocrine-disruptor testing should include fish development and fish reproduction tests, whereas a full life-cycle test could be subsequently used to refine aquatic risk assessments when necessary. For avian risk assessment, the new OECD Japanese quail reproduction test guideline provides a valuable basis for developing a test to detecting endocrine-mediated reproductive effects; this species could be used, where necessary, for an avian life-cycle test. For aquatic and terrestrial invertebrates, data from existing developmental and reproductive tests remain of high value for ecological risk assessment. High priority should be given to research into comparative endocrine physiology of invertebrates to support data extrapolation to this diverse fauna.

Derivation of predicted No-effect concentrations for lindane, 3, 4-dichloroaniline, atrazine, and copper.

Environmental risk assessment is a key feature of regulations controlling the placing of new, and the maintenance of existing, chemicals products in the market place. For example, European Commission Directive 93/67/EC on Risk Assessment for New Notified Substances and Commission Regulation (EC) No. 1488/94 on Risk Assessment for Existing Substances requires that risk assessments be carried out for new and existing substances in the European Community. The process of environmental risk assessment seeks to determine the balance of probability of species and communities being damaged by chemical releases. The process relies upon a valid estimation of a predicted environmental concentration (PEC) in relevant environmental compartments and a predicted no effect concentration (PNEC) below which the organisms present in that compartment are unlikely to be significantly affected. If the PEC exceeds the PNEC there is a potential for damaging effects to occur. This article focuses on the determination of PNECs for risk assessment. Methods for determining a PNEC described in OECD Monograph 26 (1989, Report of the OECD Workshop on Ecological Effect Assessment, Paris, France, have been applied to data derived for the four chemicals lindane, 3,4-dichloroaniline, atrazine, and copper in a series of collaborative research projects funded by the European Commission.

Development of methods to assess the effects of xenobiotics in outdoor artificial streams.

Two collaborative research projects were designed to develop and validate methods for determining the chronic effects of xenobiotics in freshwater ecosystems. The work reported here focuses on the development of methods for measuring effects on fish, invertebrates, and algae in outdoor artificial streams. 3,4-Dichloroaniline (3,4-DCA), has been used as a reference xenobiotic in two artificial stream experiments. The first used five stream channels: a control and treatments ranging from 70 to 2400 microg/liter. The second used eight stream channels--a control and treatments ranging from 0.45 to 4700 microg/liter and four coupled, 510-liter-capacity, downstream ponds-a control and treatments of 1.7, 37, and 820 microg/liter. Effects on the biota of the stream channels and the downstream ponds were examined using a range of sampling techniques and in situ toxicity tests.