Physicians are increasingly called upon to address questions related to environmental health. Pollution of air and water, contamination of food, releases from industrial facilities or waste sites, and hazards in the home are all common causes for concern among patients, community members, the media, and public officials. All health care providers should understand how to approach clinical and public health problems in environmental health, as well as the similarities and differences between occupational health and environmental health.
Although environmental issues are important worldwide, the severity and nature of the problem differs geographically, with especially serious hazards in newly industrializing countries. Many developed countries have taken significant steps in recent decades to address pervasive problems such as air pollution and contamination of drinking water. These countries continue to face issues around the safety of chemicals in consumer products, legacy contamination from historic industrial uses, and emerging concerns about recently identified chemical hazards.
Developing countries, in contrast, have faced enormous increases in industrial pollution. The dramatic expansion in motor vehicles worldwide, the shift of industrial production to nations where environmental laws are less stringent and their enforcement is often nonexistent, and the practice of shipping hazardous waste to less-developed countries for recycling or storage, have all created massive and relatively new environmental problems around the globe. In particular, air pollution and contamination of the water and food supply are very serious concerns in the developing world. Meanwhile global threats such as climate change, depletion of natural resources, and the pervasive presence of persistent bioaccumulative chemicals in the environment threaten health throughout the world.
AN APPROACH TO ENVIRONMENTAL HEALTH
Although workplace exposures to industrial chemicals are often far higher than environmental pollution levels, the latter may still be a significant concern. Lower-level exposures are an issue when the size of the exposed population is sufficient to suggest that even fairly rare or subtle health effects may have public health importance. For example, a chemical that confers a cancer risk at environmental exposure levels of one extra case per 10,000 people is of considerable importance when the base population exposed includes millions of people. Similarly, a 10 μg/dL increase in blood lead is associated with a 2–3 point decrease in IQ of exposed children. A slight decrease in IQ may not seem significant on an individual basis, but across a population of children exposed to lead such a decrement shifts the entire distribution of child IQ scores downward, resulting in a substantial increase in the number of children falling into categories that require special education services.
Although environmental exposures are often significantly lower than exposures in the workplace, there are many exceptions. For example, the populations most highly exposed to organic mercury compounds are heavy fish consumers, not industrial workers. Exposures to arsenic are frequently higher from naturally occurring arsenic contamination in drinking water worldwide than in workplace settings. Inhalation ...