Pop s organico poluentes

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Children's Health and the Environment
WHO Training Package for the Health Sector World Health Organization www.who.int/ceh
July 2008 version


To learn about POPs (persistent organic pollutants) and related substances To learnwhy and how POPs may affect children's health To identify gaps in knowledge and research needs To review international agreements and recommendations on POPs To discuss how health care providers and different stakeholders can take action to prevent exposure


Synthetic organic chemicals Persistent in environment Long-range transport leads to global pollutionLipophilic Accumulate in food chain High levels in fish and marine mammals Acute toxicity well characterized



The POPs are: Synthetic (man-made) organic chemicals – they are all synthetic chemicals, either intentionally or nonintentionally produced/released. Some are pesticides, others are industrial products or unintended by-products resulting from industrial processes or combustions(see next slide). Persistent in the environment – their persistence in the environment is remarkable – it may take them decennia or centuries to be degraded. Long-range transport leads to global pollution – Some POPs will almost always be found if tested for in tissues or environmental samples from different parts of the world. As is the case with many environmental pollutants, it is most difficultto establish that illness or disease are directly attributable to exposure to a specific persistent organic pollutant or to a group of POPs. This difficulty is further underscored by (a) the fact that POPs rarely occur as a single compound, and (b) that individual field studies are insufficient to provide compelling evidence of cause and effect in their own right. Lipophilic – they have atendency to remain in fat-rich tissues. This affinity for the adipose tissues means that POPs are likely to accumulate, persist and bioconcentrate and could, eventually, achieve toxicologically relevant concentrations – even though exposure episodes may appear limited. Accumulate in food chain – POPs enter into a cycle in nature, accumulating in the bigger animals as they eat the smaller ones. Highestlevels found in marine mammals – immune dysfunction is considered as a plausible cause for increased mortality among marine mammals. It is postulated that the consumption by seals of fish contaminated with POPs may lead to vitamin and thyroid deficiencies and cause increased susceptibility to microbial infections and reproductive disorders. Acute, high-level toxicity is well characterized – acuteeffects after high-level exposure have been described for some of the organochlorine pesticides (e.g. aldrin, dieldrin and toxaphene). PCBs have caused welldocumented episodes of mass poisoning called "Yusho" and "Yu Cheng“, that occurred in China, Province of Taiwan, and in Japan. Pregnant women exposed had no or minor symptomatology, but their children presented adverse effects and developmentaldisorders. Some are potential endocrine disrupters – this will be addressed later in the presentation. Ref: •www.pops.int/documents/background/assessreport/en/ritteren.pdf Picture above: NOAA, NURP, Wicklund. Humpback whales cruising beneath a diver. www.photolib.noaa.gov/nurp/nur02001.htm Picture below: NOAA, Captain Budd Christman. Humpback whale. www.photolib.noaa.gov/animals/anim0800.htm POPs

PESTICIDES Aldrin Dieldrin Chlordane DDT Endrin Heptachlor Mirex Toxaphene INDUSTRIAL CHEMICALS PCBs HCB UNINTENDED BYPRODUCTS Dibenzodioxins Dibenzofurans Stockholm Convention: a global treaty ratified by the international community lead by UNEP – calls for the elimination and/or phasing out of 12 POPs

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