The contamination of food by chemical hazards is a worldwide public health concern and is a leading cause of trade problems internationally…
- contamination may occur through environmental pollution of the air, water and soil, such as the case with toxic metals, PCBs and dioxins, or through the intentional use of various chemicals, such as pesticides, animal drugs and other agrochemicals. Food additives and contaminants resulting from food manufacturing and processing can also adversely affect health;
- more than 90% of the total daily human exposure to Polychlorinated Biphenyls (PCBs) and dioxins – for example - is made up of oral intake from food, whereas other routes, e.g., water, air and soil, contribute to less than 10% of total exposure.
- PCBs and dioxins belong to a class of chemicals called ‘persistent organic pollutants’ (POPs). Other POPs include furans and pesticides such as DDT/DDE, dieldrin, chlordane, toxaphene, aldrin, mirex, heptachlor and hexachlorobenzene. Years ago, these and a few other pesticides were labelled ‘the dirty dozen’ because of their nasty health effects; (1)
- besides cancer risks, especially breast cancer, POPs are associated with an array of chronic health problems: nervous system and immune system disorders, low sperm counts (these are half their historic levels in Europe), hormone disruption, learning disabilities, aggressive behaviour, reproductive problems, endometriosis and Parkinson’s disease;
- POPs are of particular concern because they persist in the environment for many years, and when they break down they sometimes degrade into substances that are no less potent. DDE, a breakdown product of the banned pesticide DDT, is an example. Some Western countries have banned many POPs for use or production, but they still remain in soils, sediments and most ominously, in the food chain;
- a 2000 study of POPs in US food found that all categories of foods – baked goods, fruit, vegetables, meat, poultry, fish and dairy products – contain POPs (the study did not test for PCBs). It wasn’t unusual for a single food item to contain residues of five or more POPs;
- many developing countries, however, still manufacture and use POPs, so the long range transport of POPs through water and the upper atmosphere remains a source of new contamination in countries where they are banned;
- once in the environment, POPs quickly migrate into the food chain, so everything contains some level of POPs. POPs concentrate in fatty tissues and they ‘bio-accumulate’ as they move up the food chain. For instance, dioxins bio-accumulate in fish at concentrations 59,000 times higher than in the water they swim in. Species and foods with higher fat content and towards the top of the food chain generally contain higher levels of POPs;
- humans, of course, are at the top of the chain, and so reap the greatest share of this toxic harvest. Scientists estimate that everyone alive today carries within her or his body at least 700 contaminants, most of which have not been well studied. According to Greenpeace, we carry in our bodies toxins at concentration levels thousands or even millions of times greater than in the surrounding environment;
- of the more than 85,000 chemicals in commerce, only a small percentage of them have ever been screened for even one potential health effect, such as cancer, reproductive toxicity, developmental toxicity, or impacts on the immune system. Among the approximately 15,000 tested, few have been studied enough to correctly estimate potential risks from exposure. Even when testing is done, each chemical is tested individually rather than in the combinations that one is exposed to in the real world. In reality, no one is ever exposed to a single chemical, but to a chemical soup, the ingredients of which may interact to cause unpredictable health effects.
(1) In this case, the word ‘organic’ has nothing to do with the certified organic food industry, which produces food without the use of pesticides, hormones, antibiotics or other chemicals. It refers instead to pollutants containing carbon-based molecules, as opposed to inorganic pollutants such as heavy metals (mercury, lead, arsenic).