Invertebrate Alternatives for Toxicity Testing: Hydra Stakes its Claim

A wide range of chemicals present in day-to-day life, including petroleum products, petrochemicals, surfactants, pesticides, pharmaceuticals, medicines, household products, food additives, agricultural run-off, by-products of farming, industrial wastes, etc., are released into the environment in large quantities. However, very little information is available about their effects on living and non-living components of the environment. For instance, several studies have shown accumulation of pesticides in groundwater in the original form (Zaki et al., 1982; Gooddy et al., 2001) or in the form of their equally or more toxic end products (Kolpin et al., 2001). A large group of chemicals derived from petrochemical sources have been reported in the ground water (Chen et al., 2000). Many pharmaceutical drugs have been detected unchanged or only slightly metabolized (Heberer, 2002) at low concentrations in sewage effluent and ground water and even in drinking water (Halling-Sørensen et al., 1998; Ternes, 1998). Around 80-100 pharmaceutical chemicals and their metabolites have been measured in both effluent and surface waters in several countries (Fent et al., 2006). Exposure of the public to inadequately tested drugs or environmental agents has resulted in several notable disasters. These include severe toxicity from the use of arsenic to treat syphilis, severe birth defects in children resulting from pregnant women using thalidomide, etc. (Melchert and List, 2007). 2 Assessment of toxicity