A new pesticide study detected trace levels of altrazine in four streams sampled along the Hamakua Coast.
The chemical, considered a restricted-use pesticide, was more commonly used during the sugar plantation days.
The samples were taken at the Kapehu, Alia, Makea and Honolii streams as part of the statewide project, conducted by state departments of health and agriculture.
Samples also were taken from two coastal areas in Kona, near the Hualalai and Waikoloa resort areas. Trace amounts of pesticides were detected in water samples at those locations.
None of the samples taken on the Big Island exceeded regulatory limits, said Fenix Grange, DOH environmental cleanup section supervisor.
The regulatory limit for altrazine is 3 parts per billion. Grange said the highest amount detected on the island was 0.075 ppb.
“It’s still in the groundwater and, therefore, still in the streams as a result,” she said. “It’s not a risk (at the detected levels).”
The study tested for glyphosate, a commonly-used herbicide, at Kapehu Stream.
Grange said other sites weren’t tested for the chemical because of higher costs of analysis and its “toxicity has been identified as being very low.” The sample didn’t detect glyphosate in the water but found it in the stream’s sediment.
That sample detected it at a level of 1,100 ppb. There are no regulatory limits for the chemical in sediment, Grange said. She said the limit for water samples is 1,800 ppb.
Trace amounts of other chemicals also were found in the streams, including two fungicides.
In all, Hawaii Island samples detected lower levels of pesticides than those taken on Oahu or Kauai, Grange said. While the samples didn’t cover all parts of the islands, she said she hopes it will lead to more discussion at the community level about these issues.
“Ultimately, pesticides have an important role in healthy agriculture,” Grange said. “We also have a great responsibility to keep our environment safe.”
To view the findings, visit http://eha-web.doh.hawaii.gov/eha-cma/Leaders/HEER/pesticides.
Email Tom Callis at email@example.com.