The Department of Health’s routine water testing has found small traces of contaminants in the water at two Maui and Big Island wells, but officials say the water is still safe to drink.
The contaminants date back to former pineapple and sugar cane cultivation.
Health officials said Tuesday they expect the already low levels of organic chemicals to continue to decrease over time, since the soil fumigants they come from have not been in use since the 1980s.
“These trace levels of the chemicals do not pose a public health threat, and the waters from these wells are safe to drink,” said Keith Kawaoka, deputy director for environmental health. “Such testing is part of scheduled monitoring regularly conducted to ensure that everyone’s water is safe to drink and public health is not compromised.”
Water from the Haiku Town Association Well had traces of dibromochloropropane (DBCP) and trichloropropane (TCP), which were once used as soil fumigants and nematicides for pineapple cultivation.
The DBCP was detected at 0.02 parts per billion — one-tenth of the federal maximum contaminant level allowed, and one-half of the state contaminant level allowed, or 0.04 ppb.
The second chemical, TCP, was found at 0.11 parts per billion at the Maui well, which is below the state maximum contaminant level of 0.6 parts per billion. The Environmental Protection Agency does not have a maximum contaminant level for TCP.
The Haiku well serves about 65 Maui residents.
On the Big Island, the Kapulena Well of the Kukuihaele water system had 0.054 parts per billion of atrazine, an herbicide used on crops such as sugar cane.
The level of atrazine has decreased over the years, with the department reporting improvement compared to a level of 0.27 parts per billion detected in 2011.
The Kapulena Well serves 450 people on the Big Island.
In the late 1970s, the EPA suspended use of all DBCP-containing products, but made an exemption to continue its use for pineapples in Hawaii. It was later in 1985 when the federal agency placed more stringent regulations on the chemical’s use. DBCP is no longer used except as an intermediate in chemical synthesis.
TCP is an environmental contaminant that was used as a soil fumigant to control nematodes on pineapple farms and banned in the early 1980s. Decades later, it is still sometimes detected in groundwater and treated tap water in Hawaii.