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Study indicates human sewage across Kaua‘i’s waters

LIHU‘E — A newly published report detected sucralose — an artificial sweetener commonly found in manufactured foods — throughout Kaua‘i’s streams and rivers, indicating nearly islandwide water contamination by human sewage.

“There’s no doubt in the science community that sucralose is an excellent indicator of the presence of human wastewater in the sample,” said Carl Berg, lead researcher and Surfrider Kaua‘i senior scientist.

“There’s no doubt. Sucralose doesn’t degrade, it doesn’t break up, it doesn’t adhere, it’s ubiquitous — it’s found all over the place. It is a scientifically demonstrated indicator of human wastewater in your sample, wherever your sample’s from.”

Both Surfrider and the state Department of Health regularly test Kaua‘i’s waters for the enterococcus bacterium, a federally recognized indicator of fecal presence in water. However, the department has on multiple occasions declined to attribute enterococcus presence to human waste, arguing the bacterium could have came from animal feces or naturally occurring bacterial colonies.

To counter this, the
Surfrider researchers chose to test for both enterococci and sucralose in their study. Because
sucralose does not occur naturally, and because it’s largely left intact as it exits the human body, the researchers say its presence across Kaua‘i’s waters leaves little doubt as to what’s polluting the island’s streams, rivers and beaches.

“If it goes right through your body and it’s only man-made, then if you find it in the environment, you know it came from a human … Nobody’s going out there and dumping sucralose — it’s coming from human consumption. Birds don’t eat it. Dogs don’t eat it. It’s coming from humans,” Berg said.

Of the 24 sites tested, only five waters (Lumahai, Limahuli and Waikoko streams and Hanapepe and Waimea rivers) tested negative for sucralose over four sets of sampling.

All 19 other sites tested positive for sucralose at least once, with all 24 sites testing positive for enterococcus.

As for where he believes the pollution is coming from, Berg did not mince his words.

“It’s coming from cesspools,” he said. “We’ve been saying this all along.”

Kaua‘i’s approximately 14,000 cesspools release untreated wastewater into the ground, contaminating the island’s groundwater.

Over time, the contaminated groundwater seeps into streams and rivers before being dumped into nearshore waters, contaminating each body of water it passes through.

In an attempt to limit this pollution, the state Legislature passed in 2017 Act 125, requiring all 88,000 of the state’s cesspools to be replaced by 2050, although the high costs of septic tank conversions has slowed these efforts.

However, Berg suggested the state Department of Health may now additionally be required by law to bolster public health precautions.

Under Hawai‘i Administrative Rule 11-54-8, warning signs must be posted “at locations where human sewage has been identified as temporarily contributing to the enterococci count.”

“In the past, (the Department of Health has) only put that warning sign up if they saw a pipe leaking or a cesspool leaking — if they actually saw the sewage,” Berg said. “They otherwise did not put up the sign. Now, we’re saying, ‘You don’t need to see it, because this chemical is showing you that human wastewater is there.’”

“I’m hoping the result of this highly accredited scientific study will lead the Department of Health to putting up warning signs in the other areas where there is high public risk,” he continued.

“We need to get a sign up on the Nawiliwili Stream. We need to get a sign up at Waipa Stream. We have a sign in Hanalei and we have a sign in Puali — what about the other streams?”

The report can be read in full at

Health department responds

In response to the study, the Department of Health’s Clean Water Branch (CWB) did not refute the researchers’ findings.

Still, the branch’s Engineering Supervisor Darryl Lum noted that under federal rules, the branch itself cannot currently make use of the researchers’ approach.

“The method used by the authors seems compelling for routine monitoring for the detection of cesspool contaminated waters; however, CWB can only use methods approved by the U.S. Environmental Protection Agency,” Lum said. “The CWB encourages the authors to submit the study for approval through EPA’s Alternative Test Procedures program under 40 CRF 136.4.”

Lum continued, noting that several independent studies have concluded enterococci can grow and multiply without a human source.

Because the Clean Water Branch’s current testing methods cannot differentiate between naturally occurring enterococci and enterococci from feces, the branch continues to notify the public whenever bacteria levels at coastal beaches exceed state thresholds.

“The CWB agrees that cesspools pose a problem in that they can potentially impact human health, as well as the aquatic life in Hawai‘i’s waters, and should be converted as soon as possible,” Lum added.


Jackson Healy, reporter, can be reached at 808-647-4966 or
Source: The Garden Island

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