How important is the environment when it comes to human health? The 1962 publication Silent Spring not only rippled throughout the scientific community and public conscience but initiated a growing wave of research into the linkages between environment and human health. (1) Yet there is limited hard scientific proof that adverse health outcomes are caused by the contaminant load that human activities add to the environment. Most scientists remain concerned about the emerging epidemic of lifestyle diseases and are committed to genetic research as the next magic bullet, while the relations between human health and environmental exposures remain highly contentious.

For example, dichlorodiphenyltrichloroethane (DDT) was indicted as an extreme risk to human health in spite of a significant lack of human toxicological or epidemiological evidence. (2) Despite the chemical’s proven ability to control, if not eradicate, the spread of mosquito-borne malaria in human populations, animal studies were deemed sufficient to warrant the ban on the use of DDT-containing agents. But recent research does not support any association between DDE (p,p’-dichlorodiphenyldichloroethylene, the predominant DDT metabolite) and, for example, breast cancer. (3) Whether or not the ban on DDT was premature or in fact beneficial to human health is still debatable. DDT remains a significant part of mosquito-control programs in malaria-endemic countries and undoubtedly saves thousands of lives.

In fact, there is much scientific debate about the causes of all cancer. Lifestyle and behavioral factors such as tobacco use and unhealthy diets are the main drivers of the cancer burden, with the World Health Organization (WHO) estimating that just 2 percent of all cancers are attributable to air pollution and only 5 percent due to occupational exposures. (4) Diseases and conditions such as diabetes, cardiovascular disease, and certain cancers have emerged as what has been coined “the epidemic of lifestyle disease.”