Improving the biodegradability in seawater test (OECD 306).

Growth and extensive urbanisation of the human population has been accompanied by increased manufacture and use of chemical compounds. To classify the fate and behaviour of these compounds in the environment, a series of international standardised biodegradation screening tests (BSTs) were developed over 30 years ago. In recent years, regulatory emphasis (e.

Aquatic exposures of chemical mixtures in urban environments: Approaches to impact assessment.

Urban regions of the world are expanding rapidly, placing additional stress on water resources. Urban water bodies serve many purposes, from washing and sources of drinking water to transport and conduits for storm drainage and effluent discharge. These water bodies receive chemical emissions arising from either single or multiple point sources, diffuse sources which can be continuous, intermittent, or seasonal.

New approach to weight-of-evidence assessment of ecotoxicological effects in regulatory decision-making.

Ecological risk assessments and risk management decisions are only as sound as the underlying information and processes to integrate them. It is important to develop transparent and reproducible procedures a priori to integrate often-heterogeneous evidence. Current weight-of-evidence (WoE) approaches for effects or hazard assessment tend to conflate aspects of the assessment of the quality of the data with the strength of the body of evidence as a whole.

Future needs and recommendations in the development of species sensitivity distributions: Estimating toxicity thresholds for aquatic ecological communities and assessing impacts of chemical exposures.

A species sensitivity distribution (SSD) is a probability model of the variation of species sensitivities to a stressor, in particular chemical exposure. The SSD approach has been used as a decision support tool in environmental protection and management since the 1980s, and the ecotoxicological, statistical, and regulatory basis and applications continue to evolve. This article summarizes the findings of a 2014 workshop held by the European Centre for Toxicology and Ecotoxicology of Chemicals and the UK Environment Agency in Amsterdam, The Netherlands, on the ecological relevance, statistical basis, and regulatory applications of SSDs.

Toward the definition of specific protection goals for the environmental risk assessment of chemicals: A perspective on environmental regulation in Europe.

This critical review examines the definition and implementation of environmental protection goals for chemicals in current European Union (EU) legislation, guidelines, and international agreements to which EU countries are party. The European chemical industry is highly regulated, and prospective environmental risk assessments (ERAs) are tailored for different classes of chemical, according to their specific hazards, uses, and environmental exposure profiles. However, environmental protection goals are often highly generic, requiring the prevention of "unacceptable" or "adverse" impacts on "biodiversity" and "ecosystems" or the "environment as a whole.

Implementing systematic review techniques in chemical risk assessment: Challenges, opportunities and recommendations.

Systematic review (SR) is a rigorous, protocol-driven approach designed to minimise error and bias when summarising the body of research evidence relevant to a specific scientific question. Taking as a comparator the use of SR in synthesising research in healthcare, we argue that SR methods could also pave the way for a "step change" in the transparency, objectivity and communication of chemical risk assessments (CRA) in Europe and elsewhere. We suggest that current controversies around the safety of certain chemicals are partly due to limitations in current CRA procedures which have contributed to ambiguity about the health risks posed by these substances.

Application of the Activity Framework for Assessing Aquatic Ecotoxicology Data for Organic Chemicals.

Toxicological research in the 1930s gave the first indications of the link between narcotic toxicity and the chemical activity of organic chemicals. More recently, chemical activity has been proposed as a novel exposure parameter that describes the fraction of saturation and that quantifies the potential for partitioning and diffusive uptake. In the present study, more than 2000 acute and chronic algal, aquatic invertebrates and fish toxicity data, as well as water solubility and melting point values, were collected from a series of sources.

From Bioavailability Science to Regulation of Organic Chemicals.

The bioavailability of organic chemicals in soil and sediment is an important area of scientific investigation for environmental scientists, although this area of study remains only partially recognized by regulators and industries working in the environmental sector. Regulators have recently started to consider bioavailability within retrospective risk assessment frameworks for organic chemicals; by doing so, realistic decision-making with regard to polluted environments can be achieved, rather than relying on the traditional approach of using total-extractable concentrations. However, implementation remains difficult because scientific developments on bioavailability are not always translated into ready-to-use approaches for regulators.

A European perspective on alternatives to animal testing for environmental hazard identification and risk assessment.

Tests with vertebrates are an integral part of environmental hazard identification and risk assessment of chemicals, plant protection products, pharmaceuticals, biocides, feed additives and effluents. These tests raise ethical and economic concerns and are considered as inappropriate for assessing all of the substances and effluents that require regulatory testing. Hence, there is a strong demand for replacement, reduction and refinement strategies and methods.

Refinement of the ECETOC approach to identify endocrine disrupting properties of chemicals in ecotoxicology.

To use and implement an assessment scheme for the evaluation of endocrine disrupting properties of chemicals in ecotoxicology, the types of effect need to be agreed. Effects that merit further consideration in this context should fulfil the following three criteria: caused by an endocrine mode of action, be adverse, and be relevant at the population level to reflect the protection goal of ecotoxicological assessments. Thereafter, a comparison of effect values, regardless of the causative mechanisms, should be made, firstly to determine if endocrine toxicity generates the lowest endpoint within a taxon, and secondly if it is the lowest endpoint compared to that of other taxa living in the same compartment.

Characterisation and expression during sex differentiation of Sox19 from the sea bass Dicentrarchus labrax.

The Sox family of transcription factors are involved in a variety of developmental processes including sex determination and gonadal differentiation. Sox19 is a particularly interesting member of this family that has been found only in fish, though mammals have a very diverged orthologue that is designated Sox15 and assigned to a different Sox family subgroup. Here we describe the cloning and characterisation of sox19 from the European sea bass (Dicentrarchus labrax), an important aquaculture species in which sex ratios skewed in favour of males are frequently encountered.

Risk assessment of endocrine active chemicals: identifying chemicals of regulatory concern.

The European regulation on plant protection products (1107/2009) (EC, 2009a), the revisions to the biocides Directive (COM[2009]267) (EC, 2009b), and the regulation concerning chemicals (Regulation (EC) No. 1907/2006 'REACH') (EC.2006) only support the marketing and use of chemical products on the basis that they do not induce endocrine disruption in humans or wildlife species.

Science based guidance for the assessment of endocrine disrupting properties of chemicals.

The European legislation on plant protection products (Regulation (EC) No. 1107/2009) and biocides (Directive 98/8/EC), as well as the regulation concerning chemicals (Regulation (EC) No. 1907/2006 'REACH') only support the marketing and use of chemical products on the basis that they do not induce endocrine disruption in humans or non-target species.

Multi-criteria decision analysis of test endpoints for detecting the effects of endocrine active substances in fish full life cycle tests.

Fish full life cycle (FFLC) tests are increasingly required in the ecotoxicological assessment of endocrine active substances. However, FFLC tests have not been internationally standardized or validated, and it is currently unclear how such tests should best be designed to provide statistically sound and ecologically relevant results. This study describes how the technique of multi-criteria decision analysis (MCDA) was used to elicit the views of fish ecologists, aquatic ecotoxicologists and statisticians on optimal experimental designs for assessing the effects of endocrine active chemicals on fish.

The fish embryo toxicity test as an animal alternative method in hazard and risk assessment and scientific research.

Animal alternatives research has historically focused on human safety assessments and has only recently been extended to environmental testing. This is particularly for those assays that involve the use of fish. A number of alternatives are being pursued by the scientific community including the fish embryo toxicity (FET) test, a proposed replacement alternative to the acute fish test.

Coordination of deiodinase and thyroid hormone receptor expression during the larval to juvenile transition in sea bream (Sparus aurata, Linnaeus).

To test the hypothesis that THs play an important role in the larval to juvenile transition in the marine teleost model, sea bream (Sparus auratus), key elements of the thyroid axis were analysed during development. Specific RT-PCR and Taqman quantitative RT-PCR were established and used to measure sea bream iodothyronine deiodinases and thyroid hormone receptor (TR) genes, respectively. Expression of deiodinases genes (D1 and D2) which encode enzymes producing T3, TRs and T4 levels start to increase at 20-30 days post-hatch (dph; beginning of metamorphosis), peak at about 45 dph (climax) and decline to early larval levels after 90-100 dph (end of metamorphosis) when fish are fully formed juveniles.

Different sox17 transcripts during sex differentiation in sea bass, Dicentrarchus labrax.

Sox genes participate in several developmental processes, including sex determination and differentiation. In this study, the genomic structure of sox17 was characterized in the sea bass (sb). Two transcripts, one producing a normal protein (sb Sox17) and another producing a truncated protein (sb t-Sox17) were detected.

Thyroid hormone receptor expression during metamorphosis of Atlantic halibut (Hippoglossus hippoglossus).

Flatfish such as the Atlantic halibut (Hippoglossus hippoglossus) undergo a dramatic metamorphosis that transforms the pelagic, symmetric larva into a benthic, cranially asymmetric juvenile. In common with amphibian metamorphosis, flatfish metamorphosis is under endocrine control with thyroid hormones being particularly important. In this report we confirm that tri-iodothyronine (T(3)) levels peak at metamorphic climax during halibut metamorphosis.

Molecular characterization and seasonal changes in gonadal expression of a thyrotropin receptor in the European sea bass.

The thyroid stimulating hormone (TSH) is a glycoprotein synthesized and secreted from thyrotrophs of the anterior pituitary gland. It acts by binding to and activating its specific receptor, the TSHR, to induce the synthesis and secretion of thyroid hormones. Recent studies conducted in diverse fish species suggest a direct role of TSH on gonadal physiology.

Identification of two isoforms of Atlantic halibut insulin-like growth factor-I receptor genes and quantitative gene expression during metamorphosis.

Insulin-like growth factor-I (IGF-I) is an important regulator of growth and development in vertebrates. Both the endocrine and paracrine actions of IGF-I are mediated through ligand-binding to a membrane-bound IGF-I receptor (IGF-IR). The characterization of this receptor and subsequent expression studies thus help elucidate the endocrine regulation of developmental processes.

Cloning of Atlantic halibut growth hormone receptor genes and quantitative gene expression during metamorphosis.

To gain insight into the possible regulatory role of the growth hormone (GH)-insulin-like growth factor I (IGF-I) system in flatfish metamorphosis, body GHR gene expression as well as IGF-I protein content was quantified in larval Atlantic halibut throughout metamorphosis (developmental stages 5-10). The cDNA of the full-length GH receptor (hhGHR) was cloned from adult liver and characterized. The hhGHR shows common features of a GHR, including a (Y/F)GEFS motif in the extracellular domain, a single transmembrane region, and an intracellular domain containing a Box 1 and Box 2.

Cloning of the promoter from the gonadal aromatase gene of the European sea bass and identification of single nucleotide polymorphisms.

Aromatase contributes to sex differentiation by catalysing the conversion of androgens into estrogens. We have cloned the promoter of the gonadal aromatase gene from the sea bass, Dicentrarchus labrax, a species whose farming is complicated by male-skewed sex ratios. The promoter shows a conserved binding site for SF-1 as well as two cAMP response elements (CREs) and putative binding sites for transcription factors belonging to the Sox and forkhead families.