Federal officials say a DNA-based water quality test, recently approved by the Environmental Protection Agency, could save health departments and other governmental agencies time, allowing government officials to close beaches more quickly in the event of a bacterial outbreak. Federal
Federal officials say a DNA-based water quality test, recently approved by the Environmental Protection Agency, could save health departments and other governmental agencies time, allowing government officials to close beaches more quickly in the event of a bacterial outbreak.
But state Department of Health Clean Water Branch Monitoring and Analysis Section Supervisor Watson Okubo said the test wouldn’t end up being much faster for the department, because the DOH doesn’t have a lab dedicated to molecular testing. Right now, the standard for testing for the presence of bacteria, particularly enterococci, is to take a water sample, filter it and create a culture. Scientists count how much bacteria is present after 24 hours to get an idea of how much of the bacteria is in the water source.
With the molecular testing, which the DOH has tried out, Okubo said the department would need to strip any other DNA from the sample container, from the lab, the counter tops, the utensils — anything a sample could come into contact with.
“There’s a lot of prep time and the filtering of the sample, that takes time,” he said.
He estimated a few hours to clean the lab, which the state uses for other kinds of testing, then a few more hours to filter the sample and complete the test, probably eight hours, at least, will have passed.
“The people who went to the beach that morning won’t know until that night” if the bacteria was present in the water, Okubo said.
Telling people in the evenings, when they’re not at the beach anyway, has about the same practical effect as taking a sample one morning, getting results the next and then notifying people, Okubo said.
Because the department performs a variety of tests, Okubo said the state would also need to spend quite a bit of time training employees to work on these specific tests.
Plus, the tests are more expensive. Dale Mikami, who also works in the Clean Water Branch, said staff take samples at West Hawaii beaches twice a week, and the number of water tests done around the state weekly would add up quickly.
U.S. Geological Survey scientist Meredith Nevers estimated the tests, at about $15 each, are nearly twice as expensive as the bacterial culture tests, which cost about $8 to perform. The test isn’t new, Nevers said, but the EPA only recently approved the test’s use to check whether water quality conforms to EPA standards.
Water quality officials around the country have tried out the tests, Nevers said, but no one is doing the tests on a routine basis.
She said the turnaround is faster.
“The advantage you’re getting is real-time results and you’re having more confidence in your results,” Nevers said. “We expect the costs will continue to come down.”
For West Hawaii residents, Okubo doesn’t see much of an advantage in the tests. The state rarely closes a beach here because of bacterial problems, which are often caused by sewage spills. Honolulu has more of those outbreaks. County officials do occasionally have to close Hilo Bay because of sewage leaks.
