Water report: No cause for concern
For the second time this year, Holton water customers have been notified that in spite of a recent violation of a drinking water standard, there is no cause for alarm.
Water customers recently received written notification that results of testing for drinking water contaminants in Holton’s water distribution system showed a larger concentration of total trihalomethanes (TTHM) in water samples than is allowed by state and federal standards. The maximum contaminant level allowed by state and federal standards is 80 parts per billion (ppb), it was reported.
According to the city’s notification, the city is required to sample for TTHMs once every quarter (three months), and compliance with state and federal standards is based on a running annual average of the four previous three-month periods. The running annual average for the second quarter of 2015, based on the previous four quarters, was listed at 89 ppb, while the running annual average for the third quarter of 2015 was listed at 90 ppb.
The running annual averages for the two quarters appears to have been skewed upward by TTHM concentrations of 130 ppb in the fourth quarter of 2014 and the first quarter of 2015. Measurements taken during the second and third quarters of 2015 were 35 ppb, and the measurement for the third quarter of 2014 was 60 ppb, all below state and federal contamination limits.
During the two quarters that skewed the running annual average upward, the city was conducting a routine free chlorine burn-out, which is part of routine maintenance of the city’s water system, according to the notification. Since March 1, the city has been using combined chlorine, which reportedly minimizes the formation of trihalomethanes.
The overall average amount, it was noted, does not pose an immediate risk, nor is there a need to resort to using bottled water, although it was reported that consumption of water containimg more TTHM than the maximum contaminant level over a period of several years may have an increased cancer risk. Anyone with specific health concerns related to TTHM is advised to consult their doctor.
In May, city officials also issued a statement saying that results for a public water standard collected during the first quarter of 2015 showed that the water system exceeded the standard for the maximum contaminant level for TTHM. The average level of TTHM measured in the city’s water over the past year was 89.5 ppb — a violation that also occurred during the free chlorine burn-out, it was reported.
Trihalomethanes are formed as a by-product predominantly when chlorine is used to disinfect water for drinking. They represent one group of chemicals generally referred to as disinfection by-products, resulting from the reaction of chlorine or bromine with organic matter present in the water being treated.
Trihalomethanes produced in the treatment process have been associated through epidemiological studies with some adverse health effects. Many governments set limits on the amount permissible in drinking water.
However, trihalomethanes are only one group of many hundreds of possible disinfection by-products — the vast majority of which are reportedly not monitored at the state or federal levels — and it has not yet been clearly demonstrated which of these is the most likely candidate for causation of negative health effects.
In the United States, the Environmental Protection Agency limits the total concentration of the four chief constituents (chloroform, bromoform, bromodichloromethane, and dibromochloromethane), referred to as total trihalomethanes (TTHM), to 80 parts per billion in treated water.
Anyone with further questions on the matter is encouraged to contact Holton City Manager Bret Bauer at 364-2721. A copy of the city’s 2015 water quality report may be found at the city’s Web site, www.holtonkansas.org
