%0 Journal Article
%T Effects of Pesticides on the Growth and Reproduction of Earthworm: A Review
%A Shahla Yasmin
%A Doris D'Souza
%J Applied and Environmental Soil Science
%D 2010
%I Hindawi Publishing Corporation
%R 10.1155/2010/678360
%X Scientific literature addressing the influence of pesticides on the growth and reproduction of earthworm is reviewed. Earthworms are considered as important bioindicators of chemical toxicity in the soil ecosystem. Studies on this aspect are important because earthworms are the common prey of many terrestrial vertebrate species such as birds and small mammals, and thus they play a key role in the biomagnification process of several soil pollutants. Majority of the studies have used mortality as an endpoint rather than subtler endpoints such as reproductive output. It is now emphasized that, whereas higher concentrations of a pollutant can easily be assessed with the acute (mortality) test, contaminated soils with lower (sublethal) pollutant concentrations require more sensitive test methods such as reproduction test in their risk assessment. 1. Introduction A greater proportion ( 80%) of biomass of terrestrial invertebrates is represented by earthworms which play an important role in structuring and increasing the nutrient content of the soil. Therefore, they can be suitable bioindicators of chemical contamination of the soil in terrestrial ecosystems providing an early warning of deterioration in soil quality [1¨C3]. This is important for protecting the health of natural environments and is of increasing interest in the context of protecting human health [4] as well as other terrestrial vertebrates which prey upon earthworms [5]. The suitability of earthworms as bioindicators in soil toxicity is largely due to the fact that they ingest large quantity of the decomposed litter, manure, and other organic matter deposited on soil, helping to convert it into rich topsoil [6, 7]. Moreover, studies have shown that earthworm skin is a significant route of contaminant uptake [8] and thus investigation of earthworm biomarkers in the ecological risk assessment (ERA) can be helpful [9] . Eisenia fetida is the standard test organism used in terrestrial ecotoxicology, because it can be easily bred on a variety of organic wastes with short generation times [10¨C13]. Its susceptibility to chemicals resembles that of true soil organisms. Sensitivity tests of multiple earthworm species have revealed that Eisenia fetida is comparatively less sensitive [14¨C16]. Although, earthworm species vary in their tolerance, reports have shown a decline in earthworm populations in response to large amounts of organic chemical deposition [17]. Mortality has been the most frequently used parameter to evaluate the chemical toxicity in earthworms [18¨C20]. It is postulated, however, that
%U http://www.hindawi.com/journals/aess/2010/678360/