Structure-activity relationships in toxicology and ecotoxicology: An assessment.

A critical assessment of the scope, applicability and limitations of structure-activity relationships (QSARs) in toxicology and ecotoxicology opens with a general explanation of QSARs and a description of the components of a QSAR (chemical descriptors, biological descriptors and the techniques used to seek a relationship between them). The main statistical terms used to assess the validity of certain types of QSAR are briefly explained and attention is drawn to a number of common errors in the statistical assessments. This is followed by a detailed analysis of 18 typical QSAR publications, which were chosen to represent the main types of chemical and biological descriptors that have been studied and a range of techniques for deriving the structure-activity relationships. A discussion of the strengths, weaknesses, applicability and limitations of QSARs is based on the above analysis, and some conclusions and recommendations are offered. The most important recommendation is that, at present, QSARs should not be used in isolation for making decisions that affect the health of humans or other species.