PT21 Environmental Assessment, Environmental Toxicology
Exhibit Hall
8:00 AM - Tuesday
(PT304) Occurrence of perchlorate in breast milk and milk available for purchase in the US.
Kirk, A1, Dasgupta, P1, Tian, K1, Anderson, T1, Smith, E1, 1 Texas Tech University, Lubbock, TX, USA
ABSTRACT- Since discovering the presence of perchlorate in cow's milk available for purchase in grocery stores in Texas, we have undertaken this study to determine the extent of perchlorate contamination of cow's milk on a national level, to determine if perchlorate is excreted in human milk, and to reach a better understanding of the contribution of non-water sources (milk) to human exposure to what has primarily been considered a contaminant of drinking water alone. We have found perchlorate to be a common milk contaminant. This finding is disturbing because it indicates that assessments of human exposures may be seriously underestimated, that perchlorate is being consumed by populations whose drinking water is free of perchlorate, and who had previously been considered unexposed, confounding a number of published epidemiological studies. The occurrence of perchlorate in the national milk supply is of great concern. Diminished exposure to maternal thyroid hormones or reduced production of thyroid hormones in the fetus, infant or young child, due to perchlorate exposure or to exposure to any other thyroid hormone disrupting factor, may result in impaired neurological development in the form of reduced intelligence or behavioral deficits. It is important to keep in mind that children are rarely, if ever, exposed to a single environmental contaminant. Lead, Polychlorinated Biphenyls (PCBs) and Polybrominated Deiphenyl Ethers all adversely affect thyroid hormone production, transport or receptor interaction. There are likely to be children in the U.S. who are exposed to multiple thyroid-hormone disrupting xenobiotics, including perchlorate, that are detrimental to their cognitive and behavioral development. Perchlorate has the potential to exacerbate the conditions of individuals hypothyroidism, or to push those with subclinical hypothyroidism to frank hypothyroidism. Lastly, perchlorate has the potential to reduce the iodide content of milk, reducing intake of this essential nutrient when adequate intake is most crucial.
Key words: breast feeding, human health, perchlorate, milk