1. The document discusses various types of pollution caused by human activities and their impacts. It defines pollution and describes different forms such as air pollution, light pollution, and point source versus non-point source pollution.
2. DDT is used as a case study to illustrate the conflicts between the utility of a substance and its environmental impacts. While DDT was widely used for malaria control, it bioaccumulated in ecosystems and contributed to thinning eggshells and declines in bird populations like bald eagles.
3. The costs of pollution are extensive and include impacts on human health, natural systems, and economic losses. Air pollution alone results in over $200 billion in lost income annually due to premature deaths.