Examination of soil values with regard to protection of soil organisms and validation of soil assessment methods
On the basis of ecotoxicological tests performed with soil organisms, recommendations for precautionary values were given for 16 metals and 10 organics. In the case of three substances (antimony, beryllium, vanadium), the amount of data was not sufficient for such a derivation, while for arsenic, lead, cadmium, chromium, cobalt, copper, molybdenum, nickel, mercury, selenium, thallium, uranium, zinc, benzo[a]pyrene (BaP), 3,4-dichloroaniline (DCA), 2,4-dichlorophenol (DCP), 1,1-bis(4-chlorphenyl)-2,2,2-trichlorethan (DDT), hexachlorocyclohexane (HCH), linear alcylbenzolsulfonic acid and -sulfonate (LAS), polycyclic aromatic hydrocarbons (PAH), pentachlorophenol (PCP), tributyltin (TBT) and trinitrotoluol (TNT), detailed proposals could be made. All recommended values were examined in a plausibility check, which focussed on similar values derived in other countries, for those substances with no existing precautionary value also regarding the background values in Germany. In contrast to previous projects where EC50 values were used, the present calculations are based on NOEC/EC10 values. Therefore, these values do not refer to the level of harm but to the level of precaution (soil values derived from EC50 values correspond to trigger values). It is recommended to close the identified data gaps in order to improve the derivation of precautionary values. Thus, in particular soil invertebrates should be tested in standard tests, but using species not yet included in the standard test guidelines.