METABOLIC FATE OF CHEMICAL AND BIOLOGICAL CONTAMINANTS
Location: Animal Metabolism-Agricultural Chemicals Research
Title: Estrogenic activity – a frame of reference for some foods, agricultural wastewaters, and animal feedstuffs.
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 19, 2011
Publication Date: November 13, 2011
Citation: Shappell, N.W. 2011. Estrogenic activity – a frame of reference for some foods, agricultural wastewaters, and animal feedstuffs. Society of Environmental Toxicology and Chemistry North America 32nd Annual Meeting, November 13-17, 2011, Boston, MA. Abstract 302. p. 70.
In the last decade, several in vitro estrogenic activity assays have been used to assess municipal and agricultural wastewaters and surface waters. Some work has been published to provide context by measuring activity from waters collected in pristine or “control” sites, but the relative estrogenic activity of “healthful” foods such as milk, or rice prepared in microwavable bags had yet to be determined. Using the E-Screen - a proliferation assay using untransfected human mammary epithelial cells, estradiol equivalents (E2Eq) were determined for extracts of milk, rice, defatted soybean meal (animal feed), water used to clean chicken eggs from a commercial processing facility (egg wash wastewater) and a 1.25mg pill of Premarin (used for human hormone replacement therapy). On a serving basis, E2Eq were: skim milk 31 -317 pg (8 oz., 5 different weeks of supermarket collection), vitamin D 4 pg (as fortified in 8 oz of milk), rice 0 – 7303 pg (48 g dry rice, 6 extracts from 4 lots), folic acid 220 pg (as fortified in 48 g rice); with no activity detected from vitamin A, niacin or thiamin (other fortifications in milk or rice). The microwavable bags used to prepare the rice contained 2 - 18 pg of E2Eq per serving (n = 6);, no estrogenic activity was found in 3 of 6 rice samples prepared in bags, and in 2 of 6 rice samples prepared without bags. The variability in E2Eq of both milk and rice is to be expected. Milk is a composite product coming from animals at various stages of lactation with variable estrogen secretion. The estrogenic activity in rice is most likely the result of trace mycotoxin contamination, such as zearalenone, and therefore highly variable. To put these values in context, Premarin contained ~300,000 pg/pill of E2Eq and defatted soybean meal used as an animal feed contained ~ 120,000 pg/g dry matter. The highest untreated egg wash wastewater contained 10 ng/L of E2Eq, approximating the proposed lowest observable effect concentration for E2 in fish. Analysis of egg wash wastewater from the holding lagoon indicated a 66% reduction in E2Eq. These data provide a broader context in which to frame past, present and future measures of estrogenic activity.