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