Could your drinking water be unsafe, even if it meets legal limits for chemicals set by the government? The nonprofit Environmental Working Group recently released a new drinking water database, including test results reported by almost every water utility in the country. Its analysis found that drinking water in the U.S., which largely meets federal and state standards, can still contain levels of contaminants which are worrisome for human health.
LISTEN to their conversation
Kara Holsopple: What did the report show about what’s in Pittsburgh’s water?
Kritina Marusic: There was a list of nine cancer-causing chemicals that were found in at least one of the 10 largest municipal drinking water systems in Allegheny County. One of the more prominent ones was bromodichloromethane. That forms when chlorine is added to water to treat it, to kill pathogens and bacteria. It combines with organic compounds that are already in the water. The chemical is classified as a “probable human carcinogen” by the Environmental Protection Agency.
It was found in water from the Pittsburgh Water and Sewer Authority (PWSA) at 16.8 parts per billion, which is nearly three times higher than the national average of 5.7, and double the state average. There’s no legal limit for this chemical.
So PWSA isn’t violating any laws by having that level of this chemical, but Environmental Working Group, which compiled this list, looked at the most recent peer-reviewed scientific literature, and studies from state and national health departments to determine what they believe is a safe level. The level of bromodichloromethane. in Pittsburgh’s water was 280 times higher than what they deem as safe.
KH: You talked with the Pittsburgh Water and Sewer Authority–PWSA–which treats water for a large part of the Pittsburgh area. What did they say in response to this report, and what are they doing?
KM: [PWSA] pointed out that they are in compliance with all state and federal drinking laws, but that they know some of these unregulated chemicals are worrisome. They said they’re working hard to reduce these levels. They also pointed out that these data, compiled in the registry, go up through 2017. So the numbers cited here were from 2016.
PWSA pointed out that they’ve been working on this issue. In 2018, they were down to 14.3 parts per billion of [bromodichloromethane] and their year-to-date level for the first three quarters of 2019 is 13.9 parts per billion. So the levels of this chemical are falling. EWG’s health guideline level is 0.06 parts per billion, so they’re not quite there yet. But they did say that they’re working on a number of strategies to try and get those levels down.
KH: You mentioned PWSA meets federal and state standards for water quality and contaminants which are regulated, but that’s not the same as the Environmental Working Group’s standard for safety. Where does their marker come from for determining what’s safe, and what’s the difference between safe and legal?
KM: I spoke with someone from EWG about this report, and she really emphasized that they want people to know that legal does not necessarily equal safe. When the government initially set up these these clean water laws, they took into account not only the absolute safest health effect level of these chemicals, but also the cost of removing them, and the best available technology, which has changed a lot in 20 years.
“EPA…says if one in every 1 million people gets cancer as a result of being exposed to bromodichloromethane over the course of their lifetime in drinking water, that’s an acceptable level of risk.”
So sometimes levels that were set as the legal standard were to give small water authorities a break. They couldn’t afford treatment for some of these chemicals. So the laws were set up to say it’s reasonable for people to be exposed to some amount of a chemical, since it’s so difficult to remove.
But now, 20 or 40 years later, the technology is really widely available and inexpensive. So there’s no reason for us to be letting higher levels of these chemicals into our water. EWG’s standard is based on this EPA number that says if one in every 1 million people gets cancer as a result of being exposed to this chemical over the course of their lifetime in drinking water, that’s an acceptable level of risk. So for bromodichloromethane, EWG’s health guideline is 0.06. That means that at that level of exposure, we could expect one in every million people to get cancer as a result of that level exposure.
KH: Is there any anything in the record that indicates where these chemicals are coming from?
KM: A lot of these chemicals are what’s called disinfection byproducts. That means that when chlorine or other treatment chemicals are added to the water to clean it before it goes out as drinking water, it can combine with organic compounds that can get into the water through things like agricultural runoff or pollution upstream.
One of the most notable sources is oil and gas wastewater. It tends to have a lot of these chemicals [that combine with chlorine to form disinfection byproducts.] One expert I spoke with, Myron Arnowitt–he’s Pennsylvania state director for the national environmental advocacy group Clean Water Action–he pointed out that anything with “bromo” in the name like Bromodichloromethane, or something we had a lot of in the region’s water called Bromoform, are all part of a category called trihalomethanes.
There is a legal limit for total trihalomethanes. They’re not regulated individually right now, but there is a federal standard for the total number of those chemicals that are allowed to be in drinking water. So of trihalomethanes, things with bromo in the name tend to be the most aggressively cancer-causing, or carry the highest level of risk. They also tend to be the ones that form as a result of contamination from the oil and gas industry.
KH: To what degree can water authorities keep these contaminants from making their way to drinking water?
KM: So both Sydney Evans, at Environmental Working Group, and Myron Arnowitt at Clean Water Action pointed out that it’s really difficult for smaller municipal water systems to clean these types of chemicals up, or to do the kind of due diligence and vigilance needed to test for them and remove chemicals that aren’t regulated.
You know, if there’s not a legal limit, they’d really be going above and beyond to test and remove these, which, as their constituents, we would hope that they’re doing because we don’t want cancer-causing chemicals in our drinking water.
But because these aren’t regulated at the federal level, and it’s so difficult to remove them, and a lot of systems don’t necessarily have the resources to do so, it’s important to keep our source water clean. One of the things Myron Arnowitt said was pollution that happens somewhere in the Allegheny River could impact as many as 17 drinking water systems downstream. So it would be much simpler to regulate that polluting industry, and make sure they’re not putting these organic compounds into the water in the first place, than it is for 17 municipalities to have to install new types of filtration and do additional testing to get these chemicals out.
KH: Is there anything that people can do, like on the consumer residents side to filter these chemicals out?
KM: One of the cool things about this database is that you can put in your zip code, and in a pull up the drinking systems in your region. Once you’re in there, and you’re looking at the contaminants, they’ll also have a chart that shows you which types of home filtration systems will remove which types of contaminants.
One thing that’s a little worrisome is that for some of these trihalomethanes, the primary means of exposure is actually inhaling them. When you take a shower, and they’re in hot water, they’re volatile, so they’re becoming small particles in the air that you can then breathe in.
Some of these filtration systems can be expensive, so most people install them at the tap, at the kitchen sink, so that they’re getting clean drinking water, and clean water for cooking. That absolutely helps, but for some of these chemicals, where the concern is actually breathing them in, in the shower, you would need whole house filtration, which becomes a lot more expensive.