Estrogen Levels in Water Alarm Scientists

Estrogen and estrogen-like compounds enter water rivers, steams and reservoirs from many sources and remain there even after passing through water treatment plants. About 80% of 139 U.S. rivers are contaminated with trace estrogen compounds. Naturally occurring estrogen compounds come from livestock urine and feces, and from human excretions which also contain contraceptives and hormone replacement medications. Other estrogen-like compounds are found in products such insecticides and plastic bottles, and they all find their way into the water supply including the drinking water supply.

The most damning evidence of the impact of estrogens in water was found in male fish swimming downstream from estrogen-containing water sources. In 2004, in Colorado, male fish were found to have both male and female sexual characteristics, such as partially developed ova, or eggs, in their testes. Fish damaged in this way have been found in the United States, Great Britain, Italy and other countries. This sex-related damage to fish may not be significant but researchers suggest that it's a warning of potential dangers to humans. Estrogens in drinking water may affect male fertility by interfering with sperm production. Links between environmental estrogenic compounds and several kinds of cancer, especially breast and testicular cancer, also have been suggested.

A 2007 study from the University of Pittsburgh Cancer Institute's Center for Environmental Oncology found that fish caught in Pittsburgh's rivers contain substances that mimic the actions the female hormone. Fish concentrate chemicals from the surrounding water in their bodies. The study results suggest that "feminizing chemicals" may be making their way into the Pennsylvania waterways.

Existing water treatment processes, which often involve naturally occurring bacteria in sewage sludge, can only remove as much as 94% of estrogen from untreated water, but what remains is still potent enough to cause damage to fish, and, researchers fear, humans. Although harmful estrogens often remain in water after treatment, this performance is not surprising, says Texas A&M Zachery Department of Civil Engineering Assistant Professor Kung-Hui (Bella) Chu, because conventional water treatment processes weren't designed to deal with estrogens.

Chu's research interests is in biological approaches to water quality problems. In wastewater treatment, this means using bacteria to clean up the wastewater. She and her colleagues are looking for bacteria to break down organic pollutants in water. Her main focus is on searching for wastewater bacteria that are capable of breaking down estrogens into harmless products

If she finds them, the estrogen degradation ability of these bacteria could be commercialized in engineered bioreactors to remove estrogens. Chu and her colleagues have found 14 different species of bacteria that can break down estrogens and are now trying to understand how these bacteria work to break down estrogens into harmless end products. All 14 bacteria break down 17ß-estradiol, a female reproductive hormone also commonly used in oral contraceptives, to a less-potent compound called estrone. Three of the 14 break down estrone further into harmless end products, and one does it particularly quickly.

Texas A&M researchers are trying to understand the enzymes and degradation pathways that the bacteria bacterium uses to destroy estrone. Their idea is to define the optimal growth conditions to promote the growth of these estrogen-degrading bacteria in biological wastewater treatment processes as a means to break down estrogens quickly and completely - and relatively inexpensively. "Adding such a bacterium could be an efficient and relatively inexpensive way to proactively avoid adverse health effects from estrogens," Chu says.