Organic Chemicals Found In Maui Water Systems
During routine sampling of drinking water systems across the state, the Hawaii State Department of Health (DOH) found minute trace amounts of certain volatile organic chemicals at the Kamole Weir clear well of the Maui Department of Water Supply’s Makawao water system and at the Consolidated Baseyard system in Wailuku. The Makawao water system serves a population of about 27,000 people, and the Baseyard system serves about 25 people.
“These findings do not represent a health threat, but the law requires us and we want to keep the public informed,” Laurence Lau, deputy director for environmental health. “The Department of Health will continue to monitor these systems to ensure that public health is not compromised.”
For the Makawao system, ethylbenzene was detected at 3.0 ppb. The federal and state Maximum Contaminant Level (MCL) is 700 ppb. The federal and state standards are set to avoid health risks based on a lifetime of consuming water containing that level of contaminant. Ethylbenzene is typically used as a solvent for coatings.
Toluene, also a solvent, was detected at 4.6 parts per billion (ppb). The federal and state MCL for toluene is 1000 ppb; m-Xylene and p-Xylene (combined) were detected at 11.0 ppb, and o-Xylene was detected at 2.8 ppb. The federal and state MCL for total Xylenes is 10,000 ppb.
These volatile organic chemicals are believed to originate in an epoxy coating that was used in the new clear well. Water tested prior to the clear well did not contain these contaminants. The concentrations found are well below the MCLs for all the contaminants. Also, the concentration of ethylbenzene, toluene, and m-Xylene/p-Xylene decreased by about 50 percent between January and February 2009.
In addition, a minute trace amount of the herbicide atrazine has been detected in the Consolidated Baseyards water system in Wailuku. 0.073 ppb has been detected. The federal and state MCL for atrazine is 3 ppb.