D10: Impact of Contaminants - Hydromod

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Integrated Water Resource Management for Important Deep European Lakes and their Catchment Areas EUROLAKES D10: Impact of Contaminants FP5_Contract No.: EVK1-CT1999-00004 Version: 4.0 Date: 25/07/01 File: D10-vers.4.0.doc Page 36 of 136 ten. Method development, validation and standardisation is necessary. Category V: tests which have actually not been conducted yet. Research should be carried out to determine whether these tests can be developed, and determine which purpose they can have in the endocrine disruption screening and testing program. The following non-mammalian tests were placed in these categories: Category II: avian reproduction, fish life cycle and mysid life cycle; Category IV: fish gonadal recrudescence; Category V: avian androgenicity screening test, invertebrate screening tests, avian multi-generation test, amphibian development and reproduction test and reptilian test. Endocrine Modulator Steering Group In June 1996 the chemical industrial organisation in Europe CEFIC (Conseil Européen de l’Industrie Chimique) - established the Endocrine Modulator Steering Group (EMSG). After a public call in The Lancet for tenders, a research programme was announced in a press release on 14 May, 1998. The EMSG programme is part of a global programme of the chemical industry, in which the Chemical Manufacturers of America (CMA) and the Japanese Chemical Industry Association (JCIA) are the other key players. With respect to wildlife EMSG will focus on fish, while the CMA concentrates on birds and reptiles. At the EDTA meeting in March 1998 the EMSG presented three proposals on tests with fish: • In vivo screening test: juvenile fathead minnows (Pimephales promelas) will be exposed for 21 days. Endpoints are induction of the egg yolk precursor vitellogenin and sex steroid levels. • Modified early life-stage (ELS) tests (enhanced OECD 210): randomly selected fathead minnow will be held without further exposure until maturity and subsequent egg-laying. In addition histological analyses of the gonads (presence of oocytes in testicular tissue and incorporation of yolk into oocytes) and biochemical analyses (vitellogenin, sex steroids and analysis of genetic sex) will be performed. • Partial life cycle test: sexually mature adult fathead minnow will be exposed for 28 days. Biological observations (daily counting of fertilised/unfertilised eggs) and histological analysis of the gonads (see above) will be carried out. On one occasion eggs will be collected. Eggs and hatched fry will then be exposed for 28 days posthatch and then follow the same procedure as described above for the ELS test. In the EDTA meeting it was discussed that also other fish species than the fathead minnow could be used for this type of toxicity testing.
Integrated Water Resource Management for Important Deep European Lakes and their Catchment Areas EUROLAKES D10: Impact of Contaminants FP5_Contract No.: EVK1-CT1999-00004 Version: 4.0 Date: 25/07/01 File: D10-vers.4.0.doc Page 37 of 136 6.4 OUTLOOK Many questions must be addressed before the overall magnitude, extent, and specific causes of this environmental concern can be resolved. Information is needed on what chemicals or class of chemicals can be considered to be genuine endocrine disrupters. The quantity (dose) of a chemical that is necessary to cause an adverse effect is important. Next, there is a need to know whether chemicals that are suspected of being endocrine disrupters act in an additive, synergistic, or antagonistic manner. While there are several available tests that are capable of evaluating a chemical for possible unique endocrine system disruption in some animal species, it is unclear which one or ones are the most useful. Therefore, it is important to determine how well current screening assays predict an adverse ecological effect due to endocrine disruption. Methods need to be (further) developed and validated to test for a cause-and-effect and a doseresponse relationship to allow for sound risk assessment and regulatory decisions to be made. Additional research is needed to (1) determine whether a (new) chemical or its metabolites have hormonal activity, and if so, what the mechanism of action is; (2) prioritise chemicals in relative potency terms of toxicity; (3) determine whether organisms are exposed to the chemical in the environment; (4) ascertain whether there are sensitive species and individuals, and (5) predict effects in the environment, including the effects on organisms, populations, communities, and ecosystems; (6) integrate the development of SAR in endocrine disruption with new data acquisition; (7) devise a source of auxiliary metabolism suitable for use with in vitro assays (8) To assess if in vitro assays can be developed to predict changes to the biosynthesis and degradation of hormones in whole organisms, and to predict changes to thyroid gland function; (9) devise novel whole organism assays for endocrine disruption in birds, fishes and invertebrates, both for their use to assess hazards to those species and to act as a possible replacement for rodent studies; (10) establish if endocrine disruption effects observed in neonates or weanlings can be predicted by measurements made in the exposed parent. Such research will resolve the question of whether there is an absolute need to conduct exposures in utero and during lactation; (11) establish a hierarchy of sensitivities for the markers of endocrine disruption in mammals, fish and birds, using a set of appropriately selected endocrine disrupters; (12) select sentinel wildlife species and endpoints for use in situations where the evaluation of an agent’s endocrine disrupting activity will most usefully commence in wildlife species. Specifically, test methods are needed to identify potential endocrine disrupters, quantify the potency of such action, and demonstrate any adverse outcome. "Sentinel" species (organisms used to detect effects of hazardous exposures) have been used to identify environmental contaminants. Therefore, there is a need to determine whether current sentinel species are adequate surrogates for identifying endocrine disrupters in wild and
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D10: Impact of Contaminants - Hydromod

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