Environmental toxicology is one of the most interdisciplinary sciences. Biologists, microbiologists, chemists, engineers, environmentalists, ecologists and other scientists work together in this new scientific discipline. Assessment of the environmental effects of chemicals is complicated as it depends on the organisms tested and involves not only the toxicity of individual chemicals, but also their interactive effects (including antagonistic and synergistic ones), and genotoxicity, mutagenicity and immunotoxicity testing. Hazardous waste management is closely related to environmental toxicology and there is a growing need for techniques and practices to minimize the environmental effects of chemicals. This volume contains the contributions presented at the 2nd Conference on Environmental Toxicology , which was held in Granada, Spain in 2008. The papers cover the following subject areas: Risk Assessment; Human Health Risk; Effluent Toxicity; Bioaccumulation of Chemicals; Biodegredation and Bioremediation; Biological Effects Monitoring; Laboratory Tests and Validation; Ecotoxicity of Emerging Chemicals; New Trends in Environmental Toxicology.