Analysis of Breast Milk to Assess Exposure to Chlorinated Contaminants in Kazakstan: High Levels of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) in Agricultural Villages of Southern Kazakstan

Abstract

To assess levels of chlorinated contaminants in breast milk, we measured organochlorine pesticides, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) in breast milk samples collected in 1994 according to the World Health Organization protocol from 92 donors that were representative of regional populations in southern Kazakstan. High levels (10-120 pg/g fat) of 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic of the PCDD/PCDF congeners, were found in breast milk samples from an agricultural region. TCDD was the major contributor (75%) to the international toxicity equivalents of these samples. The same distinctive PCDD/PCDF congener pattern was found in 15 breast milk samples and 4 serum samples collected in 1996 in a follow-up study, and has now been confirmed by three analytical laboratories.

Chemical contaminants in breast milk: time trends and regional variability.

“…Dioxins and furans have been measured in the breast milk of women from at least 35 countries, including Albania, Cambodia, Croatia, Estonia, the Faeroe Islands, India, Jordan, New Zealand, Pakistan, South Africa, Thailand, Vietnam, most European countries, and the United States (12,13,28,(69)(70)(71)(72)(73)(74)(75)(76)(77)(78)(79). The general time trend in many countries seems to be toward a slight decrease of dioxin levels in breast milk over the past decade (3).…”

Assessment of dietary exposure to some persistent organic pollutants in the Republic of Karakalpakstan of Uzbekistan.

“…A realistic hypothesis is that water and food have been contaminated with 2,3,7,8-TCDD from use of 2,4,5-trichlorophenoxyacetic acid (a component of Agent Orange), a phenoxy acid herbicide that often contains dioxin and related compounds as impurities. Although use of dioxin-contaminated 2,4,5-trichlorophenoxyacetic acid defoliant in cotton cultivation has been documented in neighboring Kazakhstan (Hooper et al 1998) and hypothesized in a recent study on prenatal dioxin exposure in the study area (Ataniyazova et al 2001), no official data confirming use of this substance in Uzbekistan are currently available.…”

“…A study in neighboring Kazakhstan lends weight to this concern over exposure via contaminated food. That study detected elevated levels of 2,3,7,8-TCDD in animal fat samples (Hooper et al 1998).…”

“…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).…”

Pesticides and Breast Cancer Risk: A Review of DDT, DDE, and Dieldrin

“…The most prevalent breakdown product of DDT-dichlorodiphenyldichloroethylene (DDE)-persists in the environment, concentrates up the food chain (20), is stored in fatty tissues of animals, fish, and humans (21)(22)(23)(24)(25)(26)(27)(28)(29), is widely detected in breast milk (30)(31)(32)(33)(34) and cows' milk (35)(36)(37), and has been detected in household dust and air (38,39).…”