Another set of Kauai drinking water quality tests, another clean bill of health

The Kauai Department of Water’s latest water quality reports reconfirm its earlier indications that pesticide and chemical contamination of drinking water is rare on Kauai.

Where it exists it is primarily from old agricultural or non-agricultural sources.

The testing confirms what county water officials have asserted for years--that the drinking water that feeds the county's water systems is extremely low in contaminants, and that most of those contaminants are from natural sources and things like corrosion of household plumbing systems.

"Our drinking water meets, or is better than, state and federal standards. We spend in excess of $400,000 in chemical and microbial testing each year to assure the safety of your water," the department said in its water quality report.

It seems to be just another confirmation of what the Kauai Pesticide Joint Fact Finding study found about chemical contamination of our community—nothing much.

The newest water studies—for 2015—are available for all Kauai communities served by the county on the Department of Water website.

The Water Department tests regularly for dozens of regulated and unregulated chemicals in drinking water.

In the West Kauai community of Waimea-Kekaha, which has been decried by some as “ground zero” for pesticide “drenching,” no pesticides at all were detected. All inorganic compounds detected are from natural soil erosion, although low levels of nitrates could be from leaking septic systems or from agricultural or residential fertilization. Nitrate levels were at less than a third of the EPA’s concern level.

Total trihalomethane, a byproduct of drinking water chlorination, was found at less than 10 percent the concern level. Lead and copper were also detected at levels below the action level—and they are believed to be from residential plumbing system corrosion.

The Hanapepe-Eleele system had similar results, with no pesticides other than water chlorination residue. The Kalaheo-Koloa system was similar again, with one exception. It showed below-action-level detection of trichloropropane, a soil fumigant also used in industrial applications like dry cleaning and as a solvent.

The Lihue-Kapaa system had a number of chemical detections, including those listed above. The tests found low levels of bromochloromethane, a fire retardant, and remnants of two pesticides, DCPA, which is used in weed control of vegetable crops, and dioxane, an industrial chemical and pesticide.

Both were measured at a fraction of a part per billion, with some samples undetectable.

Anahola’s water system was similar to Waimea-Kekaha’s, with chemicals from home plumbing systems, from natural soil and rock erosion, chlorination byproducts and very low levels of nutrients that could come from waste disposal systems or fertilizer runoff. 

Kilauea and the other North Shore Department of Water systems had generally lower levels than the already low levels of other areas. 

The reports are generally in line with a series of tests conducted earlier this year at the insistence of County Councilman Gary Hooser, who repeatedly demanded the department conduct specialized testing for the pesticide chlorpyrifos.

The Department of Water had informed Hooser that chlorpyrifos was an unlikely contaminant in groundwater, because it degrades quickly and because it is applied to the plant and not to the ground. The department noted that the University of Hawai`i and Department of Health had determined that chlorpyrifos is unlikely to leach into water. 

In spite of the department’s assertion, and after his second demand, the Department of Water in March 2016 conducted the tests and, as expected, found zero detectable chlorpyrifos in the four Kaua`i water systems tested.

They tested the water systems most likely to be exposed to chlorpyrifos—wells in Mana, Waimea and Lihue, and the Kapaia surface water treatment system. As an additional precaution, they asked their testing lab to conduct another kind of test for a series of pesticides, including chloryprifos. Once again, no detectable levels were found, the department reported.

The Department of Water response, the test results and Hooser’s letters can be found here.

Agricultural chemical detection in groundwater was more common decades ago, during the years when major sugar and pineapple farming were active, and in the years thereafter. Many of the chemicals that were at detectable levels then are no long being detected.

© Jan TenBruggencate 2016