Chemicals in Broken Arrow tap water near federal limits
BY ZACK STOYCOFF World Staff Writer
Monday, October 01, 2012
10/01/12 at 8:20 AM
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BROKEN ARROW - A water treatment mishap by the city's supplier has led to a sharp increase of two common but potentially carcinogenic groups of chemicals in Broken Arrow's tap water, officials said.
The chemicals, created when chlorine interacts with organic matter, have increased to near federal limits because of a change in the chemical mixture used to treat the water before it reaches the city, Broken Arrow Engineering Director Kenny Schwab said.
The new mixture has allowed more organic matter to remain in the water, which interacts with additional chlorine that is added when the water reaches Broken Arrow, he said.
The city's supplier, the Oklahoma Ordnance Works Authority of Pryor, has since reverted to its previous method, and levels of chlorine by-products have been dropping, Schwab said.
Federally regulated tests of Broken Arrow's water this year have recorded a 76 percent increase in the citywide average of trihalomethane since 2011 and a 51 percent jump in haloacetic acids, according to a Tulsa World analysis of records provided by the state Department of Environmental Quality and the Environmental Protection Agency.
Citywide averages are calculated by averaging the results of four annual tests at all of the city's testing sites.
Three rounds of tests so far this year have recorded citywide averages of 72.05 parts per billion for trihalomethane and 60.34 ppb for haloacetic acids. EPA limits for the chemical groups are 80 ppb and 60 ppb, respectively.
In the previous four years, both groups averaged about 40 ppb.
A final regularly scheduled round of tests in November will determine whether the city has had annual violations, which would require it to notify water customers and take steps to reduce the contaminants.
DEQ and EPA officials said the water is not a health concern at this point and that residents need to take no special precautions.
In fact, brief increases of the chemicals - typically harmful at high levels only after years of consumption - are often better than the alternative, they said.
Chlorine byproducts have been found to cause cancer in animals and have been linked with kidney and bladder problems in people.
"Disinfecting water is kind of a trade-off health-wise," EPA spokeswoman Jennah Durant said. "Obviously, people want to drink clean drinking water, and these disinfectants kill microorganisms that cause all manner of diseases, but what's left over can create these byproducts."
Although chlorine byproducts typically increase in warmer months, the increase between Broken Arrow tests in February and May this year dwarfed the summer increases of previous years.
Trihalomethanes went from 44.2 ppb to 100.3 ppb, while haloacetic acids increased from 34.5 ppb to 105.3 ppb.
Levels recorded during the next tests in August dropped to 71.6 ppb for trihalomethane and 38 ppb for haloacetic acids, and the November levels should be even lower - although maybe not enough to avoid a violation, Schwab said.
Another round of lower readings could bring the citywide averages below the federal limit, but a new method for determining compliance likely will keep the city from avoiding a violation.
Until this year, annual citywide averages were used to determine compliance.
The new method, which took effect in February, considers annual averages for each permanent testing site within a system, meaning that if one site has an annual violation, the whole system is in violation, Durant said.
Broken Arrow tests at eight sites. So far this year, five are in violation for haloacetic acids and one is in violation for trihalomethane.
The EPA takes violations case-by-case and works with water systems to reduce contaminants, Durant said. Serious violations often draw enforcement measures, she said.
Broken Arrow's contract with the Ordnance Works Authority, which provides water from the Grand River, was set to expire Dec. 31, but it has been renewed through 2013.
The city plans to begin buying some of its water that year from Tulsa. Once Broken Arrow's new treatment plant is finished in 2014, the city would pull and treat most of its water directly from the Verdigris River.
Original Print Headline: BA tap additives near limit
Zack Stoycoff 918-581-8486