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Trace amounts of soil fumigants found in private Haiku water system

Health Department says water from well is still ‘safe to drink’

Traces of two soil fumigants used in old pineapple farming operations were detected in a private Haiku water system — at levels well within federal and state safe drinking water standards — the state Health Department said Tuesday.

“These trace levels of the chemicals do not pose a public health threat,” and the water from the well is “safe to drink,” said Keith Kawaoka, deputy director for environmental health.

The presence of 1,2-Dibromochloropropane (DBCP) and 1,2,3-Trichloropropane (TCP) were detected in the Haiku Town Association Inc. HT-1 Well during routine sampling of water systems across the state. The Haiku Town Water Association system is a small residential system that serves approximately 65 people in Haiku, the Health Department said.

Drinking water from the well remains safe, the Health Department said, because the trace levels detected were below the U.S. Environmental Protection Agency and state maximum contaminant level for these chemicals. The standards are set to avoid human health risks based on a lifetime of consuming water containing that level of contaminant, the Health Department said.

DBCP and TCP are considered possible human carcinogens by the EPA, said Ann Zane, compliance section supervisor with the Health Department’s Safe Drinking Water Branch.

The DBCP level confirmed at the Haiku well was 0.02 parts per billion. This trace level is one-tenth the maximum contaminant level of the EPA, 0.2 ppb, and one-half the level of the state, which has a more stringent maximum of 0.04 ppb. EPA defines the maximum contaminant level as the highest amount allowed in drinking water.

DBCP was a soil fumigant and nematicide that was used during pineapple cultivation.

TCP was confirmed at 0.11 ppb, which is below the state maximum level of 0.6 ppb. There is no federal standard for TCP, the Health Department said.

The presence of DBCP and TCP is attributed to the former cultivation of pineapple on the site, the Health Department said. The use of the soil fumigants containing these contaminants ended in the mid-1980s, suggesting that the detected levels are not expected to increase in the future.

The system continues to be in compliance with federal and state water standards, and will continue to be monitored, the Health Department said.

When asked if there are ways to remove the chemicals completely if residents are concerned about even the trace amounts, Zane said that the best available technology to remove TCP and DBCP is granular activated carbon filtration. Residents should look for an NSF/ANSI 53 certification for reduction claims for DBCP. (There is no reduction claim for TCP). She suggested the website info.nsf.org/Certified/dwtu/.

Contamination of wells by DBCP and other agricultural chemicals in the vicinity of old pineapple fields in Upcountry and East Maui has been an issue in the past. In 2006, Maui County Council, urged on by many residents, passed a resolution calling for the Department of Water Supply not to use water from Hamakuapoko wells due to contamination with DBCP, TCP and other chemicals.

The council in 2011 allowed for the county to use the water from the wells again for agricultural purposes and during droughts. The water, which is now being filtered, later became a backup source as the county sought to reduce the Upcountry water meter wait list in 2014.

* Lee Imada can be reached at leeimada@mauinews.com.