The number of chemicals that are used in daily life is increasing at an exponential rate and are estimated to be about 50,000 with a total weight of 7 billion kg per year. Many are found in water and soil, and may act as pollutants that are hazardous to human health, and particularly to foetuses and young children. Among all these compounds, heavy metals, arsenic, phosphorus, sulfer dioxide, aflatoxines, radionuclides, tobacco smoke, and freon and other halogenated organic compounds, each are of concern.Polychlorinated organic compounds are known to be particularly dangerous because of their highly toxic effects. Among them, di oxins and dioxin-like polychlorinated biphenyls (PCBs) are by-products in numerous industrial processes. Processes involving combustion are of major importance in this regard. Other compounds that are used in agriculture or forestry, such as the pesticides DDT, hexachlorocyclohexane (HCH) and herbicides also are of concern. Each of all these lipophiliccompounds is persistent in nature and may enter the food chain and thus threathen human and animal health. After having been stored in human adipose tissues, each may cause serious consequences when released. At the Stockholm Convention on persistent organic compounds(POCs) in 2001, twelve were referred to as “the dirty dozen” because of their serious adverse effects on human well being.