Endocrine Disruptors in Drinking Water
Posted March 9, 2010
Some years ago, I was invited to speak at the Riverside County Medical Association in Southern California. A contaminant called perchlorate had been detected in the water supply, and the local physicians were concerned. I outlined the health data on perchlorate, including the fact that it blocks uptake of iodine into the thyroid gland and thereby blocks normal production of thyroid hormones. I also reviewed the science on how subtle disruption of thyroid function can permanently impair normal brain development in the fetus and neonate. Finally, I described the multiple sources of perchlorate pollution – including water contamination from rocket fuel and fireworks manufacturing. I closed by sharing the latest monitoring data, which showed that 402 public water systems serving 40.8 million people in 27 states, the District of Columbia and two U.S. territories had perchlorate in their treated water or in their water sources. California had the largest number of systems with perchlorate detections.
After my talk, an elderly physician in the audience stood up. He explained that he had spent his entire career treating patients with thyroid disease in this community. He said: “Now we learn that something in the water may be contributing to thyroid disease. What am I supposed to do about it? More importantly, what am I supposed to tell my patients? Should I tell them not to drink the water?” He went on to say: “I’m not a big fan of Government, but in this case we need the government to get involved and deal with this problem.” I agreed with him. This isn’t something health care providers and their patients should have to struggle with. This is EPA’s job.
Over five years have passed since then, and although California and other states have taken some action on this known endocrine disruptor, the EPA has failed to act.
Meanwhile, other chemicals that are known endocrine disruptors have begun turning up in water. Studies by the U.S. Geological Survey (USGS) Toxic Substances Hydrology Program have revealed an unsavory mix of pharmaceuticals, steroid hormones, unregulated pesticides, flame retardants, rocket fuel chemicals, plasticizers, detergents, and stain repellants in both the surface water and the groundwater we rely on for drinking, and in our drinking water itself. The USGS surface water study found a median of seven and as many as 38 chemical contaminants in any given water sample. Among the chemicals most commonly detected in this national survey are known and suspected endocrine disruptors, including various pesticides, triclosan, alkylphenols and alkylphenol polyethoxylates, bisphenol A, phthalates, and steroid hormones.
Unfortunately, so far the response to these findings has tended more toward “killing the messenger” rather than acting on the message. Funding for the USGS water monitoring programs, already small, has been reduced, resulting in major cutbacks in water quality sampling and less data to inform science-based decisions.
Meanwhile, over a decade has passed since EPA last promulgated a regulatory standard for a single chemical contaminant in drinking water. Now there’s a large backlog of chemicals like perchlorate that still have no regulatory standard. Others that were regulated over a decade ago are in urgent need of revision. For example, one endocrine disruptor, a phthalate chemical known as DEHP (di 2-ethylhexyl phthalate), does have a maximum contaminant level (MCL) in drinking water, but it’s terribly outdated.
Phthalate chemicals are used in an enormous range of products, such as cosmetic and personal care products, vinyl, medical devices, inks and adhesives. They are also used as inert ingredients in pesticides and until last year were in plastic toys. National monitoring studies have reported phthalates in 10 percent of surface water sources. Phthalates cause lower testosterone levels, decreased sperm counts and lower sperm quality in animals. Exposure to phthalates during development can also cause malformations of the male reproductive tract and testicular cancer. Preliminary studies in humans also show abnormalities in male reproductive development. The MCL for DEHP was set in July 1992. It was based on potential to cause gastrointestinal disturbances, nausea, and vertigo, and is not likely to protect against endocrine disrupting effects. Other phthalates have no drinking water standards at all. Bisphenol A, another known endocrine disruptor from plastics and food cans, has been detected in 20 percent of untreated drinking water sources in the U.S. and in all the monthly samples taken at the drinking water treatment plant in Jefferson Parish, Louisiana in one study. Bisphenol A also has no MCL.
The most recent Candidate Contaminant List, the CCL3, released in October 2009, includes some important drinking water contaminants, including endocrine disruptors such as perchlorate and various steroid hormones such as estriol, estrone, ethinyl estradiol, and mestranol. These are reasonable priority chemicals that deserve scrutiny and action. EPA has an opportunity to move forward with much-needed regulatory action. I hope they do so. It’s boring to sit on the SAB’s Drinking Water Committee and not have any real work to do. Seriously, I hope EPA acts because States shouldn’t have to struggle with these issues in a patchwork, alone, and people shouldn’t be drinking water contaminated with endocrine disruptors.
EPA has the authority and obligation to ensure drinking water safety. EPA should implement testing under the endocrine disruptor screening program for priority drinking water contaminants, including all chemicals on the CCL3, as well as other chemicals in pharmaceuticals and personal care products that have been detected by the USGS in surface or groundwater.
Congress needs to require EPA to prioritize and screen chemicals in drinking water, including mixtures, for endocrine disrupting effects, restore adequate funding for the USGS Toxic Substances Hydrology Program and the USGS National Water Quality Assessment Program (NAWQA), so more data are available on contaminants in our water supply, and reform the Toxic Substances Control Act to require chemical testing, and to require EPA action to promptly regulate the most hazardous chemicals.
I think that doctor down in Riverside must have retired by now, and I don’t even remember his name. But I’m thinking of colleagues such as him every time new data come out on drinking water contamination in communities across the country. What are they supposed to tell their patients? Don’t drink the water? This is why we need government action.
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