Environmentalists are criticizing New Haven’s water utility, the South Central Connecticut Regional Water Authority (RWA), for leaving two classes of carcinogenic chemicals in the drinking water. The authority responded that advocates are misconstruing the science, wrongly scaring readers into thinking that minuscule amounts are likely to cause harm.
The exchange resulted from the publication of a national water-safety database by the Environmental Working Group (EWG).
Based on numbers reported to state and federal regulators, the database, searchable by zip code, lists the chemicals found in 50,000 public utilities’ drinking water.
In New Haven, EWG warned RWA’s 430,000 customers about hexavalent chromium, the oxidized form of a lustrous, naturally-occurring metal that enters the water by erosion from rock deposits or dispersal by industrial activity, particularly steel and pulp mills, as well as several disinfectant by-products known as trihalomethanes, like chloroform and bromodichloromethane, that come from adding chlorine to the water.
RWA assured customers that they need not worry about either element. Both exist only in trace amounts in the water, far below the legal limits set by the U.S. Environmental Protection Agency (EPA), the authority reported.
What’s the discrepancy? Unlike a century ago, when the danger was waterborne pathogens that could instantly lead to an outbreak of cholera, typhoid or dysentery, today’s contaminants don’t immediately cause harm. Instead, it’s all about the risk of potentially developing health problems, usually cancer. Regulators have a tough time, then, pinpointing what’s safe and what’s not.
EWG published the database to compare “the legal limit to the ideal limit, based on health studies,” said the group’s senior scientist, David Andrews. “Often times, the legal limit involves much more than considerations of health: economic costs, political costs and much more negotiation by industry lobbying groups.”
Andrews pointed out that in the two decades since Congress amended the Safe Drinking Water Act in 1996, the EPA hasn’t set a single new regulation. It has dragged its feet on regulating perchlorate (essentially, jet fuel) and withheld a draft toxicology report on hexavalent chromium that’s been ready since 2011, he said.
“We often see utilities saying because it’s legal, it’s safe. We’re really calling that into question,” Andrews said. “We really try to highlight that and to show that many places have what is legal drinking water, but that doesn’t always mean it’s ideal based on scientific considerations.”
Anne Hulick, the director of Connecticut’s chapter of Clean Water Action, stated in an email that she is “more and more concerned” about the levels of “these very toxic chemicals” in drinking water that may not be “monitored sufficiently” or are governed by rules that are “not restrictive enough.” The group is ramping up its advocacy around these chemicals in Connecticut, she added.
RWA doesn’t mind the attention to water safety, its risks and tradeoffs, its officials said. In fact, they welcome it.
“We want the people we serve to know as much as possible about their drinking water,” said spokeswoman Kate Powell. “In our experience, the more informed people are about their tap water quality, the more confidence they have in it.” Its water quality reports are sent to customers each year.
EWG’s database flagged instances when utilities exceeded the conservative public health goals that regulators in California set, which aim to reflect the level below which there’s zero evidence of a health risk. Often, these goal benchmarks are far lower than the level at which contaminants are known to cause harm. In many cases, the goal may be unreachable for a utility, unless it pumps untold amounts of money into monitoring technology that can detect one in a trillion and the filtration systems that can pull that rare particle out.
Federal regulators set the high end by capping legal limits as close as possible to the public health goal while still remaining feasible for utilities to carry out.
“It’s important to remember that the amount of a contaminant in water matters a great deal. Simply detecting the contaminant doesn’t imply a health risk,” noted Greg Kail, a spokesman for the American Water Works Association.
That’s why the distinction between goals and limits matters, Kail argued: It helps water companies strive for safer water without chasing pipe dreams that could send their rates through the roof.
“Water is the universal solvent. There are substances in the environment — some naturally occurring, some manmade — and in many cases, they end up in the raw water supply. The question for the utility becomes how to clean the water in a way that protects public health and at the same time is affordable to the population that they’re delivering to,” Kail said. “Regulation should provide a meaningful risk reduction.
“That’s important, because a community wants to invest its dollars in ways that provide the best protection. So, if you’re going to build a treatment plant to remove a contaminant, you want to make sure there’s a real health risk there, because that’s a dollar not being spent on another risk.”
On a tour of RWA’s lab at 90 Sargent Dr., scientists showed off rooms stacked with high-tech equipment that can locate contaminants with precision. RWA tests for contaminants along a strict, federally determined schedule. Some tests require a new data point every second; others happen once every nine years. The utility pulls samples both from its treatment facilities, where 40 million gallons might come through in a single day, and from the most underutilized parts of the distribution system, where there’s a danger of water sitting around.
“Unlike wine, it doesn’t get better with age,” said Tom Barger, the authority’s water quality manager.
Both groups of chemicals that EWG highlighted in New Haven’s tap water have been regulated by the EPA since at least the early 1980s.
Disinfectant by-products posed a tricky problem for regulators, because they’re formed by purifying the water. “If you turn that down too far, you can have outbreaks of disease that come from water not being completely disinfected,” said George Gray, an environmental health professor at George Washington University’s Milken Institute School of Public Health who previously oversaw the EPA’s research. At the same time, the chemicals have been linked to anemia; problems in the liver, kidney and central nervous system; cancer, particularly in the bladder; and pregnancy complications, like reduced birth weight or miscarriage.
“You have to balance those things,” Gray added.
Under under the EPA’s current framework, the by-products are grouped together as total trihalomethanes and can’t exceed an average of 80 parts per billion (ppb). (For reference, a part per billion is roughly a single drop of water in an Olympic-sized swimming pool.) In last year’s batch of testing data, RWA said individual samples have ranged from 2 ppb to 123 ppb. On average, the level was 48 ppb.
The best way to limit these by-products is by preventing the reaction that forms them, Andrews said. Usually, that means limiting the presence of organic material — such as sewage, livestock manure, fertilizer runoff, animal corpses and fallen leaves — upstream in the source-water, with which the chlorine will later react.
“The only thing we can control is the amount of natural organic matter,” Barger said.
As one preventive measure, RWA owns and manages 27,000 acres of land surrounding seven of its water sources, creating a buffer against neighbors’ pollutants. It also conducts inspections on surrounding agricultural lands to be sure that fertilizer is properly applied and manure properly stored.
The water system also has a series of barriers to keep out other unwanted gunk.
Chromium is totaled in both its valence forms and together can’t surpass 100 parts per billion (ppb). In 2014, the most recent data available, RWA said testing for total chromium ranged from none detected to 1.10 ppb. On average, the level was 0.38 ppb.
The EPA set that level based on concerns about skin rashes, but EWG and others now believe that the metal can also cause stomach cancer and intestinal tumors — a finding that’s supported by several studies on mice and occupational exposure. The EPA is now studying whether it’s appropriate to regulate hexavalent chromium separately under its own rule — a change EWG is pushing hard for.
What’s the difference? Depending on its state, chromium can be either an essential micronutrient that our bodies need (trivalent) or a carcinogen (hexavalent), Gray explained. Problematically, he added, the metal easily switches back and forth, largely based on the water’s acidity. There’s debate in the scientific community about whether the stomach’s high acidity instantly neutralizes hexavalent chromium into a mostly harmless form or whether some slips through.
When RWA sampled for hexavalent chromium specifically, tests ranged from none detected to 0.78 ppb. The average was 0.25 ppb — one-third lower than the total chromium.
Hexavalent chromium, while naturally occurring as well, largely gets into the water supply from industrial uses, particularly steel-making, leather-tanning and wood preservation.
The utility removes chromium, along with other metals and minerals, by coagulating them together. Some of the superfine particulates — what Barger calls “colloidal particles” — are so small they’re invisible to the eye. “What we need to do to filter those out is to make those particles bigger,” Barger explains. The utility adds coagulants and polymers to the water, then essentially blends it together in a rapid mix tank. “The forced oscillation between all those particles creates a snowball, as the particles get bigger and bigger.”
The coagulated particles sinks to the bottom, where a series of rakes, for lack of a better term, collect the material into a trough. A recycling system does its best to separate the water from the particles. The liquid goes back into the blender to be sure it’s clean, while the solid goes to a lagoon where it’s consolidated, dried out and eventually sent to growers to add to their soil.
RWA also points out that, generally, the state’s tap water has far fewer issues with industrial waste than most of the country’s, because Connecticut and Rhode Island are the only two states that prohibit utilities and wastewater treatment plants from using the same bodies of water. The goal is to limit exposure to pharmaceuticals and other contaminants that might be flushed out with the treated sewage. In practice, this means most of the state’s rivers are off-limits as sources of drinking water.