(BIVN) – 20,000 gallons of sewage spilled into Kailua Bay on July 11, as a result of a broken sewer line on Ali’i Drive. The Hawaiʻi State Department of Health Clean Water Branch advised swimmers to stay out of the water the day of the discharge, but that advisory has since been lifted.

In a July 12 news podcast on the KWXX Island Issues website, host Sherry Bracken interviewed Dr. Rick Bennett, an island resident and water expert, about the possible health effects and environmental impacts of the spill. Here is a transcript from a select part of their conservation:

BENNETT: There are several impacts. The one that concerns people the most is the potential for infectious disease microbes to get into the ocean, persist long enough, and for that person that swallows that unfortunate gulp of water, they might get ill. The risk is due almost entirely to virus, not bacteria. The difficulty is, we measure bacteria – called enterococci – as a proxy. But as proxies go, it’s only 50 percent right, and 50 percent wrong.

BRACKEN: When you say we measure that particular bacteria as a proxy, what does that really mean?

BENNETT: Well, the EPA recommended enterococci – which is a genus of microbes that has about 30 members in that genus, only two of which are associated with human and animal feces, and the bacterium in and of themselves don’t present any significant risk to healthy people. In the hospital its a different story. But in the environment, no significant risk. And so the presumption is that when enterococci is present, human viruses are present. But as I indicated, that’s only true in about 50 percent of the cases. And so as indicators go, it’s a bad one.

BRACKEN: When the spill occurred, there were actually swimmers in Kailua Bay, and obviously they were told to get out of the water. So it’s not really clear how long people were exposed to the worst part of the spill. If they were exposed to the spill, but … it was like 5, 10, 15, 20 minutes – however long it took them to swim out and get out of the water – what is the risk to them of getting sick? And I know that sewage and water can cause actually a lot of different things, ranging from a rash to some of the bad diseases, gastrointestinal upsets, etc. But, help us understand more about the risk to people as you see it?

BENNETT: Sewage historically, when you had sewers running down gutters in cities, was the stuff made of epidemics. That’s just no longer the case. Most healthy people do not excrete disease-causing organisms. They just don’t reside there passively. Now however if somebody has got a case of the cruise ship virus, for example, they excrete trillions of virus particles every single day. And it only takes 1 to 10 virus particles to give you that 24 to 40 hour stomach flu.

If the virus is present, and if somebody gets it in their mouth – and you don’t even have to swallow much water to get one virus, just that that wet, salty taste that you swallow could be it – the wastewater plume that hit the ocean is going to float on the surface and follow the wind and tide currents. And if those currents took it into the swimmers lane, the risk is higher.

What we’ve seen in the last several months is that that near short current there by the [Huliheʻe] Palace tends to go over near the beach where the swimmers enter. So there may be some concentration going on. But I will be surprised if we even hear of one case of stomach flu as a result of that spill. The reason I say that is our saving grace here in Hawaiʻi is the fact that we have intense, ultraviolet sunlight. We have relatively clear water and literally in a matter of less than an hour, the sunlight is a great disinfectant of ocean water. And it’s that reason that we don’t have far, far more swimmers illnesses, given all the leaky sewer pipes and 50,000 cesspools in our watersheds.

BRACKEN: What about the environment? What’s going to be the impact to the environment of 20,000 more gallons of sewage water going into Kailua Bay?

BENNETT: Raw sewage, and the particulate matter that’s in it, can settle out on the coral reef. And that can be quite harmful. There’s actually now some supposition that sewage microbes – not human microbes, but sewage microbes – may be detrimental to some corals, although that’s very tentative at this point. The larger issue is the decades upon decades of nutrient leaching that’s going on. We’re leaching from septic systems, we’re leaching from cesspits.

Now unfortunately, the infrastructure along Aliʻi Drive – that is, the sewer – leaks. Almost all sewers leak. And they leak more and more as they get older and older. And as was suggested just recently, the pipe that broke there by the Palace was an iron pipe, that may be 50 to 60 years old. Now, I don’t know what people were thinking when they put iron in sand near the ocean, but I think we all realize you put iron in the ocean, it’s going to rust. It’s going to rust very quickly. And that’s what is happening. I’ve been told by the director of Environmental Management that most of the sewer line on Aliʻi Drive needs to be replaced.

BRACKEN: yes, Bill Kucharski has said that to me as well.

BENNETT: Yes, and we know that that sewer line has a problem with infiltration, because the wastewater now is getting too salty to use the wastewater for irrigation of plants and grasses and shrubs and things, and so we’ve got to fix those leaks. Otherwise, we’re not going to be able to reuse that 1.8 million gallons a day, which could be used to irrigate landscapes, so that people don’t have to use our precious fresh water.

Later in the interview, Bennett told Bracken that he thinks Hawaiʻi County “is in a pickle”.

“We’ve got to fix that infrastructure, there’s just no question about it,” he said.