Does a single high blood pressure reading signal impending heart failure? Absolutely not. Last month, a single state water test in Kailua Bay revealed an enterococci (ENT) Test result of 2,000 CFU per 100 ml of seawater. The action level at which warnings must issued is 130. The 2,000 result is very strongly positive but positive for what? We do not know, and there is no way to find out what happened on Nov. 8 that resulted in the high value.
The state suggests that ENT levels above 130 per 100 ml are associated with a possible increase in the risk of GI illness. However, that risk has never been evaluated in tropical ocean waters where there is no known source of wastewater discharge. The requirements for testing and the funding to conduct our state tests arises from the Beaches Act, and its provisions applied, or funding may be withheld. Thus much of our confusion is a result of sloppy legislation and the state’s attraction to its funds.
A look at the data for Station 1A on Kailua Bay shows only one exceedance in 32 samples taken over time since April this year. The vast majority of tests were completely negative. The question remains what might be the source of the bacteria, and what risk does it pose to me when I swim in the bay? As far as risk goes, we cannot know from the data. We also cannot know what the source may be. The sloppiness of the official test generates more confusion.
Enterococcus is a genus of bacteria. In that group, there are 32 species in all kinds of water environments and animals. Only two species are common to the feces of mammals. Researchers in Hawaii found ENT in streams far removed from human dwellings. ENT is native to beach sand as well as growing in the slime coating gutters and storm drains. The good news is that it is quickly inactivated in water by our intense solar UV radiation. ENT is not found in urine but is found on the skin under parts of the swimsuit.
We have analyzed two years of ENT data for the entire state. For the Kona Coast, only 1% of 1005 tests exceeded the warning threshold. In no case was the higher count sustained over time at any location. This suggests we are not detecting evidence for ongoing sewage leakage. However, this does not mean that leakage is not occurring. This is the problem with the ENT indicator. Simply put, it fails to indicate anything.
If a sample station in the bay was routinely exceeding the threshold value, further investigation must occur. But what might explain that high reading? The list is long. Events like wave actions, groundwater upwelling, an accidental discharge of a boat black water tank, a rain event flushing street water into the bay, sampling error, and even a dirty diaper in the water right at the test site can raise counts. A single event is no reason for alarm, and a series of negatives is no reason for complacency. The ENT test is simply not valid for risk determinations. Most GI illness in swimmers and surfers is due to an enteric virus. Viruses can be present when ENT is not and vice versa.
Needed is a better indicator. EPA scientists have made this declaration for decades, and the concern fails to inspire Congress to fund a better program. So, for the time being, we are stuck with the ENT test. We of Waiwai Ola Ohana are working on better tests, and local data suggests we are on track to a better indicator. Sucralose, aka Splenda, is found in hundreds of food products, and it is excreted to sewers and survives the waste treatment process entirely. We have discovered Sucralose in our wastewater and about half of the ocean sites tested so far. Three locations in Kailua Bay tested negative, whereas four sites along Alii Drive tested positive. This includes one site with sewer line service and three sites in Kahaluu where no sewer service exists, and cesspools serve the homes.
The best advice we can offer swimmers and surfers is to avoid brown water events and give the sun a full day or two to sanitize the water once it is clear. Last year, we witnessed intense algal blooms in Kailua Bay and Honokohau Harbor. Nutrient levels in both situations were elevated and fuel the bloom. Cloudy turbid waters pose a health risk to the ocean and its users. Keeping our seas clear is yet another huge challenge but our kuleana (responsibility) just the same.
R.H. Bennett Ph.D. is a member of Waiwai Ola Ohana.