Pure and Applied Chemistry

Abstract: The chlorinated organic compounds comprise a large group of compounds with a complex diversity of biologic effects and mechanisms of action. Based on the persistence and high toxicity of dioxins, PCBs, and DDT, this chapter focuses primarily on the toxicology of these organochlorine compounds. Not even these groups of compounds can be regarded as homogenous since the individual congeners show diverse environmental fates and toxicities. In this chapter, we will consider primarily the critical effects suspected to occur at human exposure at background levels, i.e. cancer, and effects on reproduction, neurobehaviour and the immune system. In recent years, interactions between these compounds and hormonal systems have received increasing attention. They have also been shown to be particularly toxic to the developing embryo, fetus and infant. In order to conduct accurate risk assessment, there is a need for further mechanistical data, and additional epidemiological studies, especially with regard to effects on reproductive, neurobehavioural and immune systems. The data presently available suggest that such effects already occur in the human population and thus, in order to reduce the exposure to these compounds, further release into the environment should be prevented.