Complex sentence: Classically, the term "environmental toxicology" refers to the study of the direct effects of environmental chemicals on human beings specifically, whereas "ecotoxicology" has been alleged to be the integration of toxicology and ecology.
Split into simpler sentences: Classically, the term "environmental toxicology" refers to the study of the direct effects of environmental chemicals on human beings, specifically. Whereas "ecotoxicology" has been alleged to be the integration of toxicology and ecology.