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The Agricultural Research Service of the U.S. Department of Agriculture has conducted a study showing that wastewater from large dairy farms is very high in estrogens which can persist for months, or even years. The levels found by the study are high enough to lower the sperm counts of fish living in the water, and cause them to develop female characteristics.
While the presence of hormones in dairy wastewater is nothing new, their ability to persist in lagoons, and their resistance to degradation is of note. Dairy waste water can contaminate drinking water, and is often stored to fertilize crops.
Hormone concentrations in livestock wastes are 100 to 1,000 times higher than those emitted from plants that treat human sewage, and large dairy farms are a primary source of estrogens in the environment, Zheng said. Recent studies have detected estrogenic hormones in soil and surrounding watersheds after dairy wastewater was sprayed on the land as fertilizer.
The study was led by scientists at the Illinois Sustainable Technology Center and appears in Environmental Science & Technology.
Via Science Daily