Tricky balancing can be required to remove lead from drinking water while also meeting other water-quality mandates.
A few years back, Madison, Wisconsin, was in a quandary about how to comply with two different federal laws. To comply with the Safe Drinking Water Act, Wisconsin regulators had ordered the municipal utility to remove lead from the water it supplies the city's oldest neighborhoods via pipes made from the toxic metal. Many cities have found it's cheaper to comply with that rule by adding corrosion- controlling orthophosphate, essentially phosphoric acid, to domestic water before pumping it through mains and distribution lines. But as city officials learned, a chemical fix would wind up causing Madison as much environmental grief as it alleviated.
That's because putting orthophosphate into the water works eventually would increase nutrient levels, which already threatened to violate the federal Clean Water Act, by further clouding the waters of local lakes. In fact, Madison just finished adding state-of-the-art phosphorus controls to its sewage system that wasn't designed to handle that much load. So local officials decided that the city had no choice but to disconnect all the underground lead pipes installed before 1928 that hooked up water mains to 11,000 structures in downtown Madison.
"There just wasn't anything that was less expensive or less disruptive to downtown," says David Denig-Chakroff, director of the Madison Water Utility. That meant spending $10 million over 10 years to run copper distribution pipes from the water main to the curb, at a cost that averages $2,000 just to replace the city-owned lines at each connection. By ordinance, the Madison Common Council also ordered property owners to replace the lead pipes running from the curb into their basement meters at the same time. The utility reimburses owners for half the tab, which has been running about $1,400 per business or household.
So far, not many American communities are going to such lengths to get toxic lead out of their drinking water. But 14 years after the U.S. Environmental Protection Agency adopted that rule, drinking water administrators in older cities across the Midwest and East Coast are still uncertain about what exactly municipal utilities should or shouldn't do to keep unsafe levels of lead from flowing through household taps. At the same time, EPA continues to churn out additional regulations. Over the next year, the agency is getting ready to impose rules ordering drinking water systems to remove disease-causing microorganisms from supplies they draw from lakes, rivers and reservoirs; reduce arsenic and radon in groundwater aquifers; and more rigorously control the chemical byproducts that treatment plants inadvertently create when they use chlorine to disinfect water for human consumption.
What's more, to stay in compliance with drinking water rules as well as the federal Clean Water Act's separate sewage treatment mandates, local governments across the country must deal with a $535 billion backlog in dealing with leaky water mains, rusty pipes, outmoded wastewater plants, overtaxed stormwater collection systems, and other long-neglected environmental infrastructure. But the Safe Drinking Water Act's contaminant-by-contaminant approach for setting tap water standards takes no account of how cumulative burdens are adding up for municipal systems and their ratepayers. As a result of that "silo" approach, taking steps to comply with one rule can make it tougher for water utilities to abide by another water-quality mandate.
That's what Madison and other cities are discovering just as public fears have flared about whether municipal governments have been vigilant enough about lead in drinking water. Lead is a naturally occurring metal, but when ingested by humans it can cause high blood pressure and kidney problems for adults; in children, it can cause brain damage and impair physical development.
By the American Water Works Association's estimate, American cities still have somewhere between 2 million and 5 million lead water service lines in use, including some that may have been installed when many centralized water systems were built in the 1800s. EPA's 1991 lead and copper standard directed utilities to test for lead in their water and to control corrosion that releases the lead from old pipes and fixtures and mixes it in the water that flows from faucets. Where testing shows that lead levels still surpass the limit, utilities must replace 7 percent of city-owned lead service lines every year until unsafe lead levels are corrected.
American Water, a leading private water company, has responded to the regulation by removing all lead service lines it owns and maintains in communities where it supplies water. Some public utilities have also begun replacing lead pipes beneath city streets as they break or as older neighborhoods come up for routine improvements.
Most big municipally run water systems, though, have tried to stay under the standard by controlling corrosion that releases lead from pipe and fixtures. That can be accomplished by increasing the pH level in water, making it less acidic, and by adding phosphate compounds that cling to the inside wall of pipes.
As local officials know well, constituents take it for granted that municipal utilities will pipe clean and safe water to their houses. Last year, many nevertheless were caught off guard when the Washington Post revealed that utilities serving the District of Columbia and other big cities had covered up tests that showed lead levels surpassing the federal government's limit in older neighborhoods. During 2003, EPA reports, lead levels exceeded the "action level" in 12 large cities and 76 smaller water systems that in combination supply water to 6 million Americans. As the numbers came to light, schools in cities around the nation began regularly flushing drinking fountain pipes.
Prodded by EPA, the District of Columbia water system accelerated lead-pipe replacement and last summer began adding corrosion- controlling orthophosphate to its water to bring lead levels down. In March, EPA announced plans to tighten rules for how all 161,000 of the country's water utilities report lead-testing results to the public and notify regulators about water-treatment changes.
But tricky balancing can be required to remove lead from drinking water while simultaneously dealing with other water-quality regulations. In 1996, for instance, Congress ordered EPA to move more quickly to tighten water-treatment standards for removing microbial pathogens, such as Cryptosporidium, which had hospitalized 4,000 people and caused 50 deaths in Milwaukee three years earlier. Simultaneously, federal and state regulators have been required to enforce limits on the potentially dangerous byproducts that form when chemical disinfectants react with soil and plant matter in raw water sources during the treatment process.
RUSHING TO JUDGMENT
Ever since 1908, American cities have added chlorine to their water to kill off the organisms that once caused devastating cholera and typhoid epidemics. Roughly 254 million Americans now drink disinfected water, but laboratory studies since the 1970s have concluded that residual chlorine and a number of its chemical byproducts themselves may cause bladder and colon cancer as well as stillbirths and spontaneous abortions in people who consume them.
A 1998 EPA rule requires public water systems to spend roughly $700 million annually to reduce byproduct formations; this year the agency is slated to follow up by ordering additional steps to intensify monitoring and prevent occasional spikes that surpass health- threatening levels, at an annual cost that EPA estimates at around another $60 million a year. To comply, water-system managers have augmented coagulation processes that remove dirt from raw water. More than a third also have switched to disinfecting water with chloramine, a combination of chlorine and ammonia.
The American Water Works Association contends that EPA's rules are rushing to judgment on disinfection without fully considering unexpected consequences. One 2004 study of chloramines-treated water in Corpus Christi, Texas, suggests "that you may be opening a Pandora's box of new disinfection byproducts, and these unregulated DBPs may be much more toxic, by orders of magnitude, than the regulated ones we're trying to avoid," says Michael J. Plewa, one of the authors and a University of Illinois genetic toxicologist.
An even more likely consequence is that how utilities control disinfection byproducts inadvertently complicates how they deal with lead. That's because stepping up coagulation and substituting chloramines disinfectant makes water more acidic, increasing corrosion when it flows through lead pipes. Washington, D.C.'s lead levels spiked after the U.S. Army Corps of Engineers switched to chloramines in 2000 for disinfecting for the water it supplies the city and its suburbs. Pending disinfection byproduct rules are expected to push water-system operators around the country to turn to chloramines, "so what you will see is that they may have to change their corrosion control programs" to keep lead levels under control, says Kevin Dixon, a Philadelphia-based Black & Veatch consultant on drinking water issues.
If corrosion control fails, then cities may have no choice but to step up their pace in replacing lead pipes. But even then, municipal utilities may have only limited reach in solving the problem. Madison's ordinance mandates that private owners replace lead lines on their property, but most water agencies can't compel a homeowner to remove the line running into his or her house, much less get rid of lead-bearing kitchen and bathroom faucets. If anything, some utility managers conclude that just replacing city owned pipes actually causes lead levels to jump temporarily by shaking debris loose--and probably produces no lasting reduction if water still flows through lead fixtures once it's inside the building. When the Greater Cincinnati Water Works took out 1,342 lead service branches in a two year period, only 84 customers chose to come up with $3,600 apiece to for finish the job all the way inside their houses. "The public wants the best drinking water they can have, but they do have a curtailment on how much they're willing to pay for it," says Jack DeMarco, Cincinnati's water quality and treatment superintendent.
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