In the US every water utility uses some form of disinfection to keep the water safe. Most use chlorine and more than 20% also use chloramine, a disinfectant that is formed by adding ammonia to chlorine. While neither of these chemicals are volatile organic compounds (VOCs), when dissolved organic carbon is present in the water, they react with it to create, amongst other things, a group of VOC’s called trihalomethanes (TTHMs). The four main TTHMs are chloroform, bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform. If you have been looking at our or the county’s VOC results you might recognize these as some of the chemicals we are detecting in highest concentrations. Finding TTHMs in public water systems is expected, though these chemicals can still have negative health effects at high enough concentrations. We recently spoke with DWS director John Stufflebean and learned that parts of the Kula water system use chlorine, and parts use chloramine. When these waters are moved from one part of the system to the other, a spike in TTHMs can occur. The director noted that this spike, which we may be seeing in our results, should be temporary and that we should expect to see levels of TTHM’s trend downwards with time.
As of September 24th, we have not found levels of total TTHMs in excess of the EPA standard of 80 ppb. However, we have found levels of chloroform that approach concerning levels according to the Minnesota Dept. of Health and levels of Bromodichloromethane that exceed the EPA’s maximum contaminant limit goal. It should be noted that these levels of TTHMs are unlikely to result in negative health effects, however it is also fairly easy to remove them with any filter that has an activated carbon component. Activated carbon filters will also remove the chlorine and depending on the specifications of the filter, may also remove chloramine from the water. We at UH-WRRC will continue to offer free tap-water VOC testing to all of Maui, which will hopefully help our communities to better understand how the fires may or may not be impacting the water systems and if elevated levels of TTHMs are indeed transient, and will return to lower levels once the system settles down.