Academic journal article Environmental Health Perspectives

Assessment of Dietary Exposure to Some Persistent Organic Pollutants in the Republic of Karakalpakstan of Uzbekistan

Academic journal article Environmental Health Perspectives

Assessment of Dietary Exposure to Some Persistent Organic Pollutants in the Republic of Karakalpakstan of Uzbekistan

Article excerpt

A 1999 study heightened long-standing concerns over persistent organic pollutant contamination in the Aral Sea area, detecting elevated levels in breast milk and cord blood of women in Karakalpakstan (western Uzbekistan). These findings prompted a collaborative research study aimed at linking such human findings with evidence of food chain contamination in the area. An international team carried out analyses of organochlorine and o ormmophosphate pesticides, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofuram (PCDFs) on samples of 12 foods commonly produced and consumed in Karakalpakstan. Analysis consistently detected long-lasting organochlorine pesticides and their metabolites in all foods of animal origin and in some vegetables such as onions and carrots--two low-cost components of many traditional dishes. Levels of PCBs were relatively low in all samples except fish. Analyses revealed high levels of PCDDs and PCDFs (together often termed "dioxins") in sheep rat, dairy cream, eggs, and edible cottonseed oil, among other foodstuffs. These findings indicate that food traditionally grown, sold, and consumed in Karakalpahtan is a major mute of human exposure to several persistent toxic contaminants, including the most toxic of dioxins, 2,3,7,8-tetrachlorodibenzo-p-oxin (2,3,7,8-TCDD). Intake estimations demonstrate that consumption of even small amounts of locally grown food may expose consumers to dioxin levels that considerably exceed the monthly tolerable dioxin intake levels set by the World Health Organization. Data presented in this study allow a first assessment of the risk associated with the consumption of certain food products in Karakalpakstan and highlight a critical public health situation. Key words: Aral Sea, Central Asia, dioxins, exposure assessment, food, organochlorine pesticides, PCBs, persistent organic pollutants, Uzbekistan.

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Soviet-era introduction of cotton monoculture in Central Asia in the 1950s began a 40-year history of intensive agricultural chemical use. Karakalpakstan, an autonomous republic within Uzbekistan, bordering the Aral Sea, was no exception. During the 1970s and 1980s, insecticide and herbicide application rates there averaged 21 kg/hectare, compared with only 5 kg/hectare throughout the Soviet Union during the same period (Bakhritdinov 1991). In addition, several compounds that were used are now banned because of their toxicity, and other agents were of doubtful origin and low chemical grade (Hooper et al. 1998). Given the persistent nature of these agents, many researchers, public health practitioners, and residents of the affected communities are concerned that this historically intensive application of toxic and low-grade agricultural chemicals is having an adverse effect on the health of the area population (Crighton et al. 2003).

Numerous studies carried out in agricultural regions of Uzbekistan (Bakhritdinov 1991; Crighton et al. 2003; Iskanderov 1986; O'Hara et al. 2000, 2001; Shafer et al. 2001; Small 1999; Small et al. 2001; Smith 1991) have clocumented a wide range of serious health problems. Findings potentially related to environmental health and toxicology include elevated levels of developmental retardation, malabsorption, hypothyroidism, immunodeficiency, and chronic renal and lung diseases among area children (Jensen et al. 1997). At this point, however, a firm scientific link between agrochemical use and health outcomes has yet to be established. Nonetheless, evidence of elevated human exposure has kept concerns high.

Recent analysis of breast milk and cord blood of women and children in Karakalpakstan showed elevated levels of hexachlorobenzene (HCB), hexachlorocyclohexane (HCH), p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and of the most toxic of dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). Dioxins in breast milk were 2.5 times the levels found in the Ukraine, and maternal 2,3,7,8-TCDD body burdens were 5 times higher than in The Netherlands (Ataniyazova et al. …

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