General recommendations for soil ecotoxicological tests suitable for the environmental risk assessment of genetically modified plants

Abstract

Before a genetically modified plant (GMP) can be placed on the market in the European Union (EU), an environmental risk assessment has to be conducted according to EU-Directive 2001/18/EC or Regulation (EC) No. 1829/2003 of the European Parliament and of the Council. However, no harmonized concept for ecotoxicological testing is available today that considers the characteristics of GMPs as a whole. In fact, to date, mainly ecotoxicological tests originally developed and standardized for pesticides are used for this purpose. Frequently in these tests, not the whole GMP is tested but only specific transgene products (mainly toxins). In this contribution, ecotoxicological methods developed for the testing of pesticides are evaluated for whether they are suitable for risk assessment of GMPs as well. In total, 105 test methods covering a wide range of terrestrial invertebrates, microbes, and plants (laboratory, semifield, and field levels) were assessed. Only 7 of them had already been used with GMPs, and in about 20 studies the existing tests methods were modified, mostly in a way such that nonstandard species were used. In the laboratory, few earthworm and nontarget arthropod (NTA) species as well as collembolans and isopods were tested, and, in the field, only the litter-bag test was used. Clearly, more species than these few standard organisms currently in use have to be selected for testing purposes. A more detailed analysis of GMP tests with soil invertebrates published in the literature revealed that some of the relevant GMP exposure routes, such as via bulk soil, soil porewater, and litter from GMPs, are well covered. However, studies addressing either consumption of GMPs themselves or secondary exposure after GMPs have been taken up by invertebrates that feed on living or dead GMPs are underrepresented.