MOREHEAD CITY, NC (WBTW) – A relatively new technology means a huge step forward in detecting dangerous bacteria at the beach. In South Carolina, the current water test takes at least a day before swimmers get a warning. A newer test cuts the time to about an hour, but South Carolina and many other states are not using it.
The newer way to test ocean water may sound complicated, but it is what many became familiar with on the CBS show CSI: Crime Scene Investigation. It’s basically a DNA test called quantitative polymerase chain reactions or qPCR. Dr. Rachel Noble at the UNC Institute of Marine Sciences in Morehead City, North Carolina, often calls it a “quantitative PCR test.”
“The type of technology we use is used in hospitals all over the world,” she explained.
Dr. Noble developed a way for the test to detect enterococcus bacteria in ocean water. Those bacteria indicate water that could make you sick or even cause skin problems.
News13 first reported on the old enterococcus testing method in 2016. It takes 24 hours to get results, and it’s still used by South Carolina’s Department of Health and Environmental Control (DHEC).*
The new test involves putting water samples into a machine, and it gives bacteria results in about an hour. Dr. Noble said it is possible for a test to be done at 8 a.m. and have results ready to share with the public by 11 a.m.
“Before most families will put a towel down at the beach,” she said.
Dr. Noble said there have been studies on the newer testing method to see how it compares to the established method. She said it has proven to be just as accurate as the old method.
“The EPA actually recommended these tests for use in 2012,” Dr. Noble said, “but they recommended them without a wide scale plan to assist many of the users.”
She believes getting states to adopt it for their beach water testing really comes down to motivation.
“In some cases there’s not a lot of incentive for them to focus on beach water quality because in a lot of cases the beach water quality is quite good,” she said.
Dr. Noble still hopes states or even smaller counties or municipalities will be motivated to start using the rapid water test for an economic benefit because it could be used to notify beachgoers not just of high bacteria levels, but also of clean water each day.
“If you were the first to begin a wide scale program to maintain and rapidly test your beaches – at least your high-use beaches – you would have a scenario where people according to social media would begin to prefer those beaches because of those testing programs, and the economics would literally take care of itself,” Dr. Noble said. “If there was an opportunity for them to see the economic benefit, they would do it immediately because the costs related with outfitting a laboratory and being able to use the rapid tests is far, far, far below the number of dollars that are brought in each year from our coastal states in tourism.”
She says California, Hawaii and all the Great Lakes states are working to incorporate versions of the rapid water test in some way.
As for cost, Dr. Noble says the expense of the new test is now about the same as the old one. The newer test does require a little more training because the computerized results are more abstract than the old test method.
The faster method will only result in quicker notices in our area if DHEC decides to adopt it. South Carolina’s DHEC tests beach water from May through October. The department has not replied to requests for comment on this newer testing method.
*The 24 hour delay of the current enterococcus test combined with DHEC’s policy means the public often is never notified that the water sampled had dangerous levels of bacteria at the time of sampling. Also, many of the notices about dangerous bacteria levels are made two days after the water was sampled. South Carolina and several other states in the southeast follow the EPA’s minimum standard.
According to DHEC’s policy, a swimming advisory would be posted a day after a test if the enterococcus level was above 500 cfu/100mL. The advisory happens the next day because of the 24 hours needed to get test results. If the enterococcus level was 104-499 cfu/100mL in the first test, a second test would be done. Once results of the second test are available at least 24 hours later, an advisory would be posted if the second test also showed enterococcus above 104.
For example, if a sample is taken Thursday morning, results won’t be back until Friday morning. If the results show enterococcus above 500 cfu/100mL, a swimming advisory is issued immediately on Friday. If the enterococcus level is between 104 and 499 cfu/100mL, DHEC’s policy requires a second test. Results of the second test would be available Saturday morning, and an advisory would only be issued if that second test also shows enterococcus levels above 104. That Saturday morning advisory would be in reference to water first tested on Thursday morning.
Anyone headed to the beach can check DHEC’s water testing results, which are done about once a week between May and October. Details and a link to the beach reports are available on DHEC’s beach monitoring website.
