Lead and cadmium are long established toxic and carcinogenic metals. Still, the mechanisms of their interaction with eukaryotic DNA are not unequivocally understood. New data provide evidence on the influence of both metals on DNA repair, particularly non-homologous end joining (NHEJ) and mismatch repair (MMR). This may help explain the weak direct mutagenicity of both Pb2+ and Cd2+ ions in the Ames test, as opposed to the proven carcinogenicity of both metals; it has long been proposed that lead and cadmium may induce an imbalance in mammalian systems of DNA damage repair and promote genomic instability. While new evidence for mechanistic interactions of metals with DNA repair emerges, some of the old questions involving dose distribution, pathways of exposure and bioaccumulation/detoxification kinetics still remain valid. To help place the current state of the art in the genetic toxicology of lead and cadmium within the context of ecotoxicology, the current authors propose an integrative approach and offer a review of other authors’ work as well as some of their own data on systemic and organ-specific toxicities in laboratory mice. The current chapter is a comparative analysis of the state of the art in the specific toxicity and genotoxicity of Pb and Cd, presenting some new and little-known information.
Part of the book: Genotoxicity and Mutagenicity
Radionuclide contamination poses serious hazards for terrestrial ecosystems. Beyond the readily apparent damage to the biota at high doses, low doses of ionizing radiation produce stochastic effects: mutation, carcinogenesis, and genomic instability. The proposed chapter is a review of the biological and ecological effects of radionuclides. The authors discuss, beyond the Chernobyl accident, other contamination events. The review includes the biological and ecological effects of the three principal technogenic contaminants in terrestrial ecosystems: Cs-137, Sr-90, and I-131. Ecological risks to terrestrial small mammals are assessed in detail. In addition, the chapter provides some of the lesser-known methods of remediation and detoxification, including the use of modified natural zeolites as environmental remedies and bio-sorbents. Presented herein is little-known information on environmental protection against radioactive contamination.
Part of the book: The Toxicity of Environmental Pollutants