Environmental Pollutants, a Threat for Children
The fetal and early postnatal are the most vulnerable periods of life, when even relatively small disturbances can lead to permanent damage. Relatively unknown risks for the fetus and young infant are environmental pollutants - compounds, present in the environment that can affect human health. Studies have shown that these compounds may have negative effects on birth weight, psychomotor and sexual development, endocrine organs like the thyroid gland, immune responses and the development of diseases in later life. Different sources of environmental pollutants and different products can be distinguished: 1. compounds produced and used шт industrial processes, 2. compounds used in household and personal care, 3. pesticides used in agriculture, 4. pollution caused by mining, 5. air pollution caused by traffic, 6. smoking by parents. Among dangerous compounds produced and used in industrial processes are Polychlorinated Biphenyls (PCBs) and Brominated compounds (BCs), among products which are used in households and personal care - bisphenol A, phthalates, lead, methyl mercury. Pesticides - DDT and organophosphates - are the compounds of special interest. DDT despite it had been used extensively in the 1950s and 1960s and was banned 50 years ago is known to be harmful even now. Traffic, producing gases like NO2, Co2 as well as very small particles (PM 10, PM 2.5) and elemental carbon, is an important source of environmental pollutants. Smoking, mainly by parents, is another very important thread to children. Studies have shown that nickel mining and smelting result in the production of high concentrations of sulferdioxide gas. The air is also polluted by very small particles, the most dangerous part of air pollution. Though theoretically living besides nickel mining and melting plants is dangerous, nowadays studies on the effects of nickel mining on children seem to be lacking. While almost all compounds have effect on the brain, the endocrine system, the immune system and the cardiovascular system, mode of their action might be different. The mode of action of many substances is not well known. PCBs and many other compounds are endocrine disruptors, affecting the thyroid and sexual hormones. It is unclear however if effects on the thyroid hormones are the cause of brain damage. There might also be a direct effect of PCBs and other substances on the development of organs. Another mechanism of action of these pollutants might be to influence gene expression by epigenetics. The activity of genes might be affected, what can have results in next generations. This epigenetic effect has been shown for pesticides in animal studies, effects were seen till the fourth generation. Epigenetics might also been involved in the effects of smoking.