Warm weather causes rise in BA water's chlorine by-products
BY ZACK STOYCOFF World Staff Writer
Tuesday, October 02, 2012
10/02/12 at 4:41 AM
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PRYOR - An increase of chlorine byproducts in Broken Arrow's tap water can be linked to unusually warm weather that complicated treatment efforts earlier this year, the city's supplier said.
Two groups of chemicals created when chlorine interacts with organic matter spiked in spring after the city added a routine dose of chlorine to water pretreated by the Oklahoma Ordnance Works Authority in Pryor.
The authority normally adjusts its pretreatment mixture between May and October to compensate for higher levels of organic particles, which increase in warmer months, General Manager Larry Williams said.
This year, warm temperatures came before the scheduled adjustment and allowed more organic matter to interact with chlorine, he said.
The average level of trihalomethane in Broken Arrow's water increased from 44.2 parts per billion in February to 100.3 parts per billion in May, while haloacetic acids rose from 30 parts per billion to 105.3 parts per billion, according to Environmental Protection Agency records of citywide tests.
The chemical groups - linked to cancer and other ailments when consumed at high levels for many years - are federally limited to 80 parts per billion and 60 parts per billion, respectively.
Citywide annual averages have since dropped to near those levels, and environmental officials said water users were never in danger.
The Ordnance Works Authority is prepared to adjust its pretreatment mixture earlier next year, if necessary, Williams said.
The authority sells water from the Hudson River to Broken Arrow, Pryor, Chouteau, two smaller communities and seven rural water districts in Craig, Mayes, Rogers and Wagoner counties.
"We take the quality of our water very seriously," Williams said. "You can be guaranteed that our (summer) window is now an elongated window. We'll be watching that very, very carefully."
Northeastern Oklahoma had one of its warmest spring seasons on record, with Tulsa's average monthly temperatures ranging from 5 to 10 degrees above normal.
In May, the Ordnance Works Authority tested trihalomethane and haloacetic acids above federal limits at its own MidAmerica Industrial Park facility.
The authority then adjusted its treatment mixture, which reduced the levels in follow-up tests within the next two weeks, Williams said.
Broken Arrow, which tests its water at eight sites four times a year, has recorded lower levels in its lone round of citywide tests so far since May, EPA records show.
The tests in August found an average 71.6 parts per billion for trihalomethane and 38 parts per billion for haloacetic acids.
That has brought the citywide annual averages to 72 parts per billion and 60 parts per billion, respectively.
However, six of Broken Arrow's sites are in violation for trihalomethane or haloacetic acids so far this year.
A new federal rule determines compliance based on the annual average of each individual testing site, so a final round of tests in November will determine whether any site has had a violation.
That would require the city to notify its water customers and take steps to reduce the contaminants.
Broken Arrow's contract with the Ordnance Works Authority has been extended from Dec. 31 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: Hot weather cited in BA water issue
Zack Stoycoff 918-581-8486
zack.stoycoff@tulsaworld.com
