The popular misconception that oral contraceptives are the main reason behind the oestrogen content in drinking water supplies has been disproved in a new study.
Scientists have found that the pill accounts for less than 1 percent of the estrogens found in drinking water.
The report suggests that most of the sex hormone - source of concern as an endocrine disruptor with possible adverse effects on people and wildlife - enters drinking water supplies from other sources.
Analysis by Amber Wise, Kacie O'Brien and Tracey Woodruff found that 17 alpha-ethinylestradiol (EE2) has a lower predicted concentration in U.S. drinking water than natural estrogens from soy and dairy products and animal waste used untreated as a farm fertilizer.
And all humans, (men, women and children, and especially pregnant women) excrete hormones in their urine, not just women taking the pill.
Some research cited in the report suggests that animal manure accounts for 90 percent of estrogens in the environment.
Other research estimates that if just 1 percent of the estrogens in livestock waste reached waterways, it would comprise 15 percent of the estrogens in the world's water supply.
The report appears in ACS' biweekly journal Environmental Science and Technology.