A new study using novel technology has found historically high bacteria counts at two major beaches in southeastern Kauai are not related to human waste, according to the state Health Department. But community groups on Kauai have come forward, disagreeing with the reported results of the study.
The state contracted the Lawrence Berkeley National Laboratory to use its unique DNA sequencing technology to track the source of the high bacteria counts in the area, which have consistently prompted warning signs to go up at Mahaulepu Beach and Waiopili Stream.
The Surfrider Foundation calls Waiopili Stream “the most polluted stream” of those it samples on Kauai. “This freshwater stream is extremely polluted, and it is highly recommended to stay out of it,” the foundation says on its swim guide website.
The PhyloChip, a microbial source tracking tool, was used for the first time in Hawaii to study the Mahaulepu and Waikomo watersheds.
After analysis, Berkeley Lab microbial ecologists Gary Andersen and Eric Dubinsky found no signs of fecal indicator bacteria in the waters, the state Health Department said.
“We conducted a study using the latest technology available and determined the high bacteria counts in Mahaulepu Valley, which have been a concern for many years, is not linked to any human sewage sources in the area,” said state Health Director Bruce Anderson in a news release. “With this new information, we can assure the public that recreational waters in Waiopili Stream and nearby beaches do not pose an imminent health threat to swimmers.”
The state said the lab’s findings validate the results of a similar 2016 survey of Waiopili Ditch in Mahaulepu Valley, which was conducted at the time in response to concerns raised by the Surfrider Foundation’s Kauai Chapter.
Members of Kauai Surfrider, however, are not yet convinced the water can be declared safe from bacteria.
“I applaud the Department of Health trying new technologies to better understand our water safety,” said John P. Alderete, a microbiologist and Surfrider’s Blue Water Task Force coordinator. “Unfortunately, this … is still a test the EPA has not approved.”
Alderete also said the conclusions drawn by the Health Department are inconsistent with the data from the study.
Surfrider conducts its own routine tests on water quality, and has found two-thirds of waterways to be chronically contaminated with fecal-indicating bacteria. Alderete said further study of the watersheds is needed before declaring them safe.
Bridget Hammerquist, president of Friends of Maha‘ulepu, the group that successfully fought a proposed industrial dairy in Mahaulepu Valley, called the declaration of safety an outright “fraud on the public.”
“Throughout our fight to keep an industrial dairy from operating dangerously close to our drinking water and ocean, we were always concerned about the outrageous fecal bacteria counts in the Waiopili Stream,” she wrote in an email.
Further study is needed, she said. A decent study, for instance, on the impacts of a human biosolids dump site that operated for 11 years should also be conducted on the soil and groundwater in the area.
“Instead of ignoring it, let’s identify it and fix it,” she said. “This isn’t helping anyone. It’s not protecting our babies, our vulnerable people. It’s a disaster and it needs to be addressed.”
The PhyloChip, a device the size of a credit card, uses DNA sequencing to test for nearly 60,000 bacterial species instead of using more traditional bacteria culture tests to detect their presence.
Samples of stream water were tested and compared with the microbial data collected from area cesspools and the droppings of local livestock, including cattle, pigs, horses, chickens and wild nene geese.
The results are more comprehensive and accurate than culturing, which can result in many false positives, according to Anderson.
While researchers were unable to pinpoint exact sources, they concluded that there was no detectable human sewage in the Mahaulepu watershed, or a significant presence of livestock or avian wildlife fecal matter. They concluded that high counts of fecal indicator bacteria in some areas of the Mahaulepu watershed may be from cows and feral pigs but were isolated incidents.
“That allays some of our fears, that the high counts are not from human waste,” said Janet Hashimoto of the state’s clean-water branch.
The Berkeley Lab analyzed samples from 13 inland and coastal sites taken during a year and concluded there was no detectable human sewage in the Mahaulepu watershed.
Also, they found no fecal indicators at Makauwahi Cave, believed to be a possible conduit for wastewater bacteria from the Koloa and Poipu area.
The scientists, however, found that a coastal seep along the beachfront of the Poipu resort area had been contaminated with human fecal matter by a nearby hotel’s sewage well. Samples there matched those found in injection wells.
The site had not been identified by past monitoring using traditional tests.
The Berkeley Lab scientists suggested that the historically high fecal indicator levels may likely be from “old-school testing methods” not designed for use in tropical regions.
Both enterococci and Clostridium perfringens typically grow inside animal digestive tracts, and can flourish in environments outside of their biological hosts, such as soil, in tropical regions like Hawaii due to heat and humidity, the scientists said. The natural presence of these organisms in water does not necessarily put people at greater risk of gastrointestinal illness.
The EPA, however, mandates the testing of enterococci for beaches across the nation. If water samples contain enterococci levels exceeding the threshold level of 130 colony-forming units per 100 milliliters, then the public must be informed.
Measuring enterococci is not a good indicator for most Hawaii waters, said state environmental health specialist Myron Honda.
“Our weather conditions foster the growth of enterococci, and this can cause undue concern,” said Honda. “We recognize the science and rationale behind our samplings and methods are complex, and we hope to have the opportunity to explain it in plain terms at next week’s public meeting on Kauai.”
Until a more appropriate indicator of health risks in Hawaii waters is approved, the state Health Department said it will continue water quality tests according to federal guidelines.
Berkeley scientists said the PhyloChip has been used to monitor water in the San Francisco Bay Area, tropical waters around coral reefs and in Singapore.
While the state Health Department would like to test other waters in Hawaii with the PhyloChip, said Hashimoto, it will not be likely because it costs more.
A community meeting to discuss the study is scheduled for 4-6 p.m. Wednesday at the Kauai District Health Office, 3040 Umi St., Lihue.