LIHUE — After a second round of sampling, the state Department of Health suspects human waste may be the source of pollution ending up in Waiopili Stream in Mahaulepu.
One possibility is that people are using the old guard shack, located on Grove Farm Land near the entrance to the Makauwahi Cave Reserve, as a toilet, Watson Okubo, monitoring and analysis section chief of DOH’s Clean Water Branch, wrote in an email.
Of the 11 sites tested on the property — spanning from the reservoir in upper Mahaulepu Valley down to the mouth of Waiopili Stream — the sample taken nearest the guard shack tallied the highest counts of fecal indicating bacteria, including enterococci and clostridium.
“Either someone is dumping sewage or the shack is used as a restroom,” Okubo wrote.
Initially, after visiting and testing the site Nov. 5-6, Okubo said he believed animals — chickens, sheep, geese and feral pigs — on Grove Farm property were responsible for the high counts, but that additional sampling was needed to confirm it. A second round of testing was conducted Nov. 24. This time, samples were sent to both a DOH lab and the City and County of Honolulu Laboratory at Sand Island for analysis. While the Honolulu lab tallied higher levels of enterococci, DOH found higher levels of clostridium.
The overall trend, Okubo said, is that bacteria counts increase from mauka to makai, with a giant spike near the guard shack.
“You cannot have that kind of big, significant jump (in bacteria counts) from just having feral pigs in the area,” he said.
Waiopili flows off Grove Farm land and enters the ocean near Makauwahi Cave Reserve and downhill from Hawaii Dairy Farms’ proposed dairy site. Recent testing has shown it is currently Kauai’s most polluted stream — one of several that continuously fails to meet state water quality standards.
In a single 100 ml sample, there should be less than 104 counted enterococcus — bacteria which indicates contamination from feces of warm-blooded animals, including humans. If the count exceeds 104, the water is considered polluted. The geometric average, or geomean, of five collected samples should not exceed more than 35 bacteria per 100 ml.
In a single sample taken at the guard shack and sent to the Honolulu lab, 28,000 enterococcus bacteria were present — 269 times the Hawaii state standard. At the bridge crossing the stream near Makauwahi Cave, 17,000 bacteria were present.
Of the 11 samples sent to the Honolulu lab, only one met state water quality standards, according to information provided by Okubo.
The highest clostridium count — 340 bacteria in a 100 ml sample — was also found at the guard shack.
Carl Berg, head of Surfrider Foundation of Kauai’s Blue Water Task Force, who first alerted DOH of the situation at Waiopili, said he questions how the guard shack could be the source of pollution when DOH collected its samples upstream of the actual structure.
Regardless of the source, human or animal, Berg says the public must be warned. Scientific studies, he said, have shown cattle manure is as much of a public health risk as human waste.
“With counts as high as as 28,000 … these waters pose a definite health risk to people who walk through or children who play at the mouth of the river and in the ocean contaminated by animals’ wastes,” he said.
And now that DOH suspects the source is human, the department has a moral and legal obligation to post warning signs, according to Berg.
“We have known of the high counts of fecal indicating bacteria since March,” he said. “If DOH does not put signs up immediately, I hope that the landowner, Grove Farm, will do the right thing for the community and post at the stream mouth themselves.”
Given the high counts that were found, Okubo said he has a “hunch” the source may be human. However, to be sure, DOH will conduct additional tests Dec. 15.
If the source is found to be human, DOH would be required to post warning signs in the area, which Grove Farm would be responsible for, according to Okubo.
Grove Farm did not return messages.