Assessment of the potential germ cell mutagenicity of industrial and plant protection chemicals as part of an integrated study of genotoxicity in vitro and in vivo.

An approach is described that enables the germ cell mutagenicity of chemicals to be assessed as part of an integrated assessment of genotoxic potential. It is recommended, first, that the genotoxicity of a chemical be defined by appropriate studies in vitro. This should involve use of the Salmonella mutation assay and an assay for the induction of chromosomal aberrations, but supplementary assays may be indicated in specific instances.

Identification of immunotoxic effects of chemicals and assessment of their relevance to man.

Immunotoxicity is defined as the adverse effects of foreign substances (xenobiotics) on the immune system. Two types of effects are possible: immunosuppression (which may result in an increased susceptibility to infection or to the development of tumours) and immunopotentiation (which may manifest as an allergy or as autoimmunity). There is, as yet, little evidence that well controlled occupational exposure to industrial chemicals has led to clinically significant immunosuppression.

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.