A CRITIQUE OF THE HAWAII DEPARTMENT OF HEALTH PRESS RELEASE ABOUT THE KAUAI WATERSHED FECAL BACTERIA STUDY:
Mahaulepu and Waikomo Watersheds PhyloChip Source Tracking Study, Hawaii
RH BENNETT PhD
Applied Life Sciences LLC
The following is a scientific critique of the Hawaii Department of Health water quality study: press release. It is substantially remedial to the point of purposeful disinformation. I have been working as an infectious disease microbiologist, in the area of water quality for over 40 years, 20 years in Hawaii, and the balance in the West and internationally. The controversy is anything but new.
The full UC Berkeley study is available at the link in the references
The Press Release June 5, 2019
HONOLULU – A new Hawai‘i Department of Health (DOH) water quality study shows high bacteria counts historically observed in the Māhāʻulepū sand Waikomo watersheds on Kaua‘i are not associated with human waste.
The study did not attempt to account for historical levels of the official DOH Indicator Bacteria, the genus Enterococci, and the species Clostridium perfringens. Instead, the study examined for genetic evidence of the gut microbiomes of common animals, including human. The indicator bacteria are not the least human-specific. The ENT test has a fecal ENT detection error of 50% (4).
While researchers were unable to pinpoint the exact sources of the bacteria, they conclusively determined human waste is not the cause of bacterial contamination in the water. The study is now available to the public online through the department’s Clean Water Branch webpage.
The study design could not determine the “exact source,” instead it can be determined if the fecal bacteria genetic signal was from a particular animal species and in many observations, animal fecal signals were detected. Human fecal signals were not detected in the watersheds at the time of testing. It cannot determine what happened in the past.
“We conducted a study using the latest technology available and determined the high bacteria counts in Māhāʻulepū Valley, which have been a concern for many years, is not linked to any human sewage sources in the area,” said Health Director Bruce Anderson. “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.”
There are no sewer systems, per se, in the watershed. Rather there are cesspits and wastewater injection wells. A human fecal signal was detected in wastewater injection wells and from a water seepage site near the coast. A tracer study in West Maui clearly showed an injection well ocean connection (5).
Seawater was not tested so NO estimation of swimmer’s risk can be stated for other than wishful inference without data to support it.
DOH contracted the Lawrence Berkeley National Laboratory (Berkeley Lab) to understand better what may be contributing to the periodic high bacteria counts in the area. Their findings validated the results of a similar sanitary survey from 2016.
The study was not designed to understand the periodic high bacteria counts (ENT and CP) The data from the DOH and this study are NOT directly comparable as the DOH tests are not accepted as a valid indicator (3,8) even though the EPA requires it for the states use of federal Beach Act funding.
What the study did show is that at this time there is little if any evidence of human fecal signals in the creek watershed. How long a signal would persist after having a strong signal in these watersheds is not known. ENT has some persistence in the environment (1,10).
Using PhyloChip, an innovative microbial source tracking tool, the Berkeley Lab scientists found that neither human nor animal waste is the sources of any high counts of traditional fecal indicator bacteria, such as enterococci and Clostridium perfringens, in the Kaua‘i watersheds.
Phylochip is not just a microbial tracking tool. It is a broad genetic probe designed to broadly identify bacteria in an environmental setting where there is likely to be a mix of fecal bacteria types from different species. Its strength comes from the fact that the microbes need not be grown in the lab to identify them. In the environment, there a significant number of bacteria we do not know how to grow in the lab, and more importantly, there are stressed bacteria that are alive but do not grow. This is a significant weakness of traditional diagnostic microbiology, like the ENT assay.
It is a misnomer to call the official tests fecal indicators as both bacteria are ubiquitous in the environment. ENT can be found in large number is beach sand and must not be interpreted to imply fecal contamination (10). Similarly, CP is common to soils.
“We plan to hold community meetings later this summer on Kaua‘i to thoroughly explain the survey findings and will give the public an opportunity to ask questions of state health officials and Berkeley Lab scientists,” Anderson added. “While this is a great step forward in understanding human health risks associated with the presence of bacteria in water in this area of Kaua‘i, this is certainly not the end. Further research like this Kaua‘i study is needed to guide the department in making health and safety recommendations to the public.”
Berkeley Lab microbial ecologists, Gary Andersen, Ph.D., and Eric Dubinsky, Ph.D., led the survey efforts with the support of DOH’s Clean Water Branch.
DOH failed to state the EPA is the major funder of the project and the release of the final report was months in the making
After completing this survey and finding no evidence of widespread sewage system leaks, the Berkeley Lab ecologists proposed that the high counts of fecal indicator bacteria in Kaua‘i’s waters are likely due to the use of traditional tests for enterococci and Clostridium perfringens, which were not designed for use in tropical regions. Enterococci and other bacterial indicators are naturally found in soils and other animals and flourish in environments outside of their typical biological hosts. The ecologists note that this phenomenon is common in humid, tropical settings like Hawai‘i.
According to the maps on the study, there are very few onsite wastewater systems, known as cesspits in the watershed. Only three coastal seeps were tested, and one had a pronounced human fecal signature. It did not test groundwater in areas of high cesspit density; thus, the conclusion about system “leaks” is without substantiation. Tidal action is known to move bacteria from groundwater into the sea (6). While the warm moist tropical environment is conducive to the survival of bacteria in general, the study did not examine the extent to which they “flourish” implying they grown and reproduce. The extended survival of the indicators is documented even in cool climates (7).
A recent state study reports groundwater contamination risks from cesspits (9).
The study shows that the natural presence of these bacteria in water does not necessarily put people at higher risk of gastrointestinal illness. Until a more appropriate and valid indicator of health risks in Hawai‘i waters can be determined, the health department will continue testing according to federal guidelines and standards.
Many studies from a wide variety of beach settings have shown that the indicator bacteria used by DOH do not correlate with increases swimmer risk of infection (2,3).
Studies conducted by the EPA where there was a strong correlation are in waters where there is known wastewater or sewage release. Such was the case for the Honolulu area as partially treated sewage is no longer discharged to the ocean.
Additional significant findings from the study include:
• High counts of fecal indicator bacteria in some areas of the Māhāʻulepū watershed may be from cows and feral pigs, but these were isolated incidences and popular beach areas downstream from these areas were clean.
The meaning of clean is not a term used in descriptive microbiology, and its use is misleading.
• There is no connection between the Makauwahi Cave and the Māhāʻulepū watershed as a conduit for fecal contamination, which was one pollution source posed as a hypothesis after the completion of the 2016 study.
It would be more precise to state that no connection was apparent. Given the nature of volcanic geology, conduits cannot be ruled out. The data suggested there was no connection at the time.
• In the Po‘ipū area, one coastal seep showed that there may possibly be pollution linked to injection wells. However, the routine coastal beach monitoring in the Po‘ipū area by DOH does not indicate chronic high counts of fecal indicator bacteria.
This is a very misleading statement. There was a strong human fecal signal in Seep 6. It is contaminated; its exact source was not investigated. However, the most likely source given the volume of wastewater dumped into the well. No wastewater injection well in the state is required to determine the fate of the wastewater. Given the penetration of seawater into the subterranean estuary, a hydrologic connection to the sea is well established in a great many locations in Hawaii.
Researchers Andersen and Dubinsky applied the Phylochip with scientific rigor as we should expect. They did show quite conclusively that a widespread human fecal microbial signature was not present, at the time, in two Kauai watersheds. If there were a septage dump in the watershed, over time, microbial decay would reduce the human signal. That research has yet to be conducted. Wastewater injection wells had a very strong human fecal signature. One nearby seep also had a strong human signature.
They did demonstrate again what others have shown, that ENT and CP are nonspecific markers and can yield high numbers in the absence of a human fecal signature or other definitive testing. This relationship is well known at HDOH, the EPA, and to most all water quality researchers. Its continued use is an artifact of poor public policy at both the federal and state levels. We are remise when we make excuses for a diagnostic test with a 50% error rate. We would not tolerate an HIV blood test that was wrong half of the time. It would never get FDA approval.
As always in research answers raise more questions. The key question is now, what is the extent to which human fecal bacteria signatures occur in the nearshore beach water and how long to they persist. We know that ENT is a statistically invalid indicator for recreation waters. ENT has a 90% die-off rate in cool marine water of 22 to 122 hours in the absence of sunlight. Sun UV can lower ENT counts in a matter of a few hours. Thus samples collected from 10 to 2 PM can be false negatives as demonstrated in Florida (11).
GI Illness from recreation exposure to human waste-contaminated water is not due to bacteria; it is due to the Enteric virus (8), such as the Norovirus aka the Cruise Ship Virus. Thus, needed are studies to sample marine waters with the Phylochip and measure the enteric virus. Only then can we pronounce with some confidence, the relative GI safety of our recreation waters.
Andersen, G, and Dubinsky E., Mahaulepu and Waikomo Watersheds PhyloChip Source Tracking Study, Hawaii
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