Statistical Treatment of Ecotoxicological Data based on Hazard Modelling

When characterising complex chemical pollution i.e. pesticide polluted groundwater or testing the effects of chemical compounds on the environment, ecotoxicological tests are of great value. This is due to their sensitivity and their expression of the overall toxicity. Since environmental pollution is increasing it is judged that ecotoxicological assays will have increasing impact on the toxicity- and risk assessment of environmental pollution.
Evaluating results from ecotoxicological tests inevitably include estimation of dose-response relations. Conclusions about toxicity of the pollution or tested chemicals are summarised in characteristics extracted from the dose-response relationship.
A revision of the statistical methods for extracting these measures has been internationally recommended by the scientific community. The dose/time-response models used are based on biological considerations, the key assumption is that the hazard rate is proportional to the concentration of the chemical compound in the animal as far as it exceeds the no-effect level. The uptake dynamics are described by a one compartment model involving the uptake rate and elimination rate. The dynamic models are compared with the traditional models, regarding the number of parameters, description of experimental data etc.