The term ecotoxicology is defined it as "the branch of toxicology concerned with the study of toxic effects, caused by natural or synthetic pollutants, to the constituents of ecosystems, animal (including human), vegetable and microbial, in an integral context". Ecotoxicology is alleged to be the integration of toxicology and ecology or, "ecology in the presence of toxicants". It aims to predict the effects upon natural populations, communities, or ecosystems - 'the ecosystem' -- of stressors, be they anthropogenic in origin or otherwise. It differs from Environmental Toxicology in that it integrates the effects of stressors across all levels of biological organisation from the molecular to whole communities and ecosystems, whereas environmental toxicology focuses upon effects upon the individual. This book brings together important research from around the world in this subject.