Rincon streamsampling small

Report shows threat from pesticides is greatest on Oahu, not Kauai

Sampling by the DOH reveals Oahu's urban streams have the highest number of pesticides, but that most pesticide levels are still below EPA benchmarks.

Will Caron

The Hawaii Department of Health (DOH), in partnership with the Hawaii Department of Agriculture (DOA) and the United States Geological Survey (USGS) has completed a draft of results from a pilot project of state wide pesticide sampling, conducted after the DOH received numerous inquiries from members of the community, largely, from Kauai.

The pilot project measured pesticides in surface water and sediment at 24 locations across the State to create “a comprehensive suite of currently used pesticides,” according to the report. “The sites were selected with help from local stakeholders to represent four different land uses, each with differing pesticide use practices. Locations were chosen in areas across the state where currently used pesticides have the potential to enter local surface waters and/or the near shore marine environment.”

A total of 136 different pesticides or breakdown products were detected during the survey. All the surveyed locations had at least one of these pesticides or breakdown products present, but only one pesticide—a “historically used” termiticide called Dieldrin—exceeded state and federal water regulatory limits. Five other pesticide compounds were detected at levels exceeding the most conservative Environmental Protection Agency (EPA) aquatic life benchmark. However, all other pesticides detected were lower than even the most stringent aquatic or human health guideline value set by the EPA.

The results of the project show that the highest number of different pesticides detected in surface water and sediment were in urban streams in Honolulu, as opposed to water and sediment near farms on Kauai.

“Land use significantly impacted the number and type of pesticides detected,” reads the report.  “Oahu’s urban streams had the highest number of different pesticides detected. Manoa Stream at the University of Hawaii showed 20 different pesticides and breakdown products.”

For Marjorie Ziegler, director of the Conservation Council for Hawaii, this was the primary takeaway from the report. “The myth in my head says that [Genetically modified organisms are] increasing all those pesticides, but maybe that isn’t the case,” Ziegler said after the draft was released.

Results from Kauai show that, “Atrazine and metolachlor, two restricted-use herbicides, were detected on Kauai at agricultural sites downstream of seed crop operations. One location had levels that exceed aquatic life guidelines, but remain below regulatory standards.”

The report notes that Atrazine was the most commonly found pesticide in the study and that, of the sites tested, 80 percent had atrazine present. However, only two sites—one on Kauai and one on Maui—reflected “elevated concentrations suggestive of current use of atrazine.” All of the remaining atrazine detections were at trace level concentrations far below state and Federal benchmarks.

Lastly, the project analyzed seven sites for the presence of glyphosate, the herbicide more commonly known as Roundup. Three of the seven sites had glyphosate, but all at extremely low levels.

The report has already been praised by pro-Genetically Modified Organism (GMO) groups and blasted on message boards by anti-GMO folks, despite the fact that the terms “GMO” and “Genetically modified organisms” do not appear anywhere in the draft.

The Hawaii Crop Improvement Association, a pro-GMO farmers group, released the following statement yesterday:

We applaud the Hawaii Departments of Health and Agriculture as well as the U.S. Geological Survey’s efforts to present factual pesticide sampling information for public and legislative benefit.  A quantitative, unbiased study such as this can serve to shed light on issues of public concern and allay fears.  The Hawaii Crop Improvement Association is fully committed to minimizing the environmental impact of pesticide use and being good stewards of the land, and we believe this study is evidence that our existing efforts and best management practices are working.

However, the report does note that, “These findings represent a snapshot in time from a single sampling event within watersheds with multiple upstream inputs. While they provide useful information about pesticide occurrence across different land uses, they may not be representative of typical conditions or identify specific sources.”

What this means for Kauai’s fledgling pesticide disclosure and buffer law and other similar efforts on Maui and Hawaii island remains to be seen.