Ref ID : 1915
D.J. Spurgeon, M.A. Tomlin, and S.P. Hopkin; Influence of temperature on the toxicity of zinc to the earthworm Eisenia fetida. Bull.Environ.Contam.Toxicol. 58:283-290, 1997
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A range of toxicity test have been proposed to assess the potential hazards of pollutants to earthworms. Of these, the two acute toxicity tests using Eisenia fetida recommended by the OECD (1984) and EEC (1985) have become routinely used in the risk assessment and regulation of new and existing chemicals. In addition to the acute tests, procedures have also been proposed for measuring the sub-lethal effects of chemicals on parameter such as reproduction and weight change. In both the lethal and sub-lethal toxicity test developed with worms, attempts have been made to standardise test conditions to allow results from different laboratories to be directly compared. However, variability in exposure conditions and responses are fundamental to determine the effects of pollutants under natural conditions. In the field, conditions such as light, moisture availability, pH, temperature and humidity all fluctuate over time. Such variations affect both the sensitivity and exposure of individuals to toxic chemicals. Hence when evaluating the potential effects of pollutants, it may be important to know how changes in test conditions influence toxicity. Temperature is one of the most important environmental conditions standardised in lethal and sub-lethal toxicity tests. However, little data are available on its influence on the responses of earthworms to toxicants. In the tests proposed by the OECD (1984), Kokta (1993) and Van Gestel et al. (1989) a standard temperature 20 degrees C is used to maximise growth and cocoon production, whilst maximising survival. In the field, earthworms can be exposed to toxicants at temperatures both above and below 20 degrees C. Hence, in the present paper we have assessed the effects of different temperatures on the lethal and sub-lethal toxicity of zinc for the earthworm Eisenia fetida. Zinc was chosen for this work, since previous studies have indicated that this metal is most likely to be limiting the abundance of earthworms close to a smelter situated at Avonmouth in South-west England.