Eating is now a risky business for millions of people who are exposed to such man-made contaminants as lead and mercury, according to a group of leading physicians.

Physicians for Social Responsibility (PSR) warns that the slow but steady poisoning of basic foods like milk or fish constitutes a growing concern for poor people in particular.

The 1985 Nobel Peace Prize-winning body released its findings in a 244-page report: Critical Condition: Human Health and the Environment. The study is a medical response to the 1992 Earth Summit in Rio de Janeiro.

PSR President Elizabeth Bowe and Howard Hu, assistant professor of Environmental Health at Harvard University, warn that poor people are more likely to ingest contaminated food than their richer counterparts.

"Exposure to environmental food contamination may not be borne equally," they say.

They report that roughly three quarters of US toxic waste disposal sites which have failed to comply with government safety standards are in impoverished black communities. They also say that contaminated food is more likely to affect poorly fed men, women and children because "malnutrition weakens the immune system, thus making an affected person more vulnerable to infectious pathogens and possibly to chemical agents."

Conditions in the developing world, including illiteracy, inadequate sanitation and the lack of personal protective equipment, also increase the risk of entire communities to contaminated food, they say. Bowen and Hu report that, increasingly, "the integrity of food is threatened by a number of man-made pollutants that can be introduced at any step in the food chain and in the food processing industry."

There have been a number of instances in which high-level poisoning has occurred through human error and negligence, including at least 37 epidemics directly due to pesticide contamination, the report says. Pesticides, including herbicides, insecticides, food preservatives and plant growth hormones, are the most common source of food contamination, particularly in developing countries where toxic pesticides continue to be exported.

Bowen and Hu say a recent study in Asia found high levels of chemical pesticides in preserved fruit, eggs and fish, while a study in Morocco found the presence of chlorinated pesticides in over 80% of sampled eggs, poultry and bovine meat.

The authors note that in the case of Morocco, 7.5% of samples had levels higher than international tolerance levels.

The PSR authors cite lead-contaminated food as a major concern because of its prevalence globally and because studies linking brain damage with relatively minute quantities of lead in human tissue.

One million children in the United States alone are exposed to enough lead in food to cause lead poisoning - a disease that takes its toll by impairing the learning capacity of the child. An estimated four million US women of childbearing age are exposed to excessive amounts of environmental lead, but even greater numbers may be at risk in Eastern Europe and the former Soviet Union.

Bowen and Hu say that lead is a frequent contaminant of water which may be used to irrigate crops or to process food in factories and homes, and can be found in glazed ceramic ware or in crystal glassware. In many countries still using leaded fuel, airborne particles and soil contaminants from its combustion still make up the dominant sources of lead exposure, especially for children.

The report says that food and beverage cans manufacured outside the United States still contain lead solder which can leach into food.

Lead compounds are also used deliberately in substantial quantities in a variety of folk medicines and cosmetics and such toxic exposures have been reported among residents of China, India, the Middle East and Latin America.

But lead is not the only metal to contaminate food. Cadmium, copper, and mercury are other highly toxic metals that enter food through agricultural and industrial applications. Moreover the processing or cooking of food is generally not effective in neutralising their impact. Common domestic sources of exposure to these toxic metals are teapots, cooking utensils, metal pans and packaging materials.

Source: Third World Resurgence No. 39.