By QING ZHANG
Capital News Service
LANSING – The number of closings or health safety advisories due to pollution at Michigan’s more than 1,200 public and nearly 500 private beaches has dropped the past three years.
“Surface water quality is generally showing improvement where programs are in place to correct problems and restore water quality,” according to the 2014 Integrated Report for Water Quality and Pollution Control in Michigan by the state’s Department of Environmental Quality.
But taking the long view, parts of the state’s coastal environment may not be as promising as they appear.
“All our nearshore waters are at risk,” said Joan Rose, the director of the Water Quality and Environmental Microbiology Laboratory at Michigan State University. “No surprise, in urban areas things are more serious.”
Rose’s lab has studied cores of sediments from the bottom of Lake St. Clair and found that water quality deteriorated over the past 100 years.
The deeper the sediment, the older it is. Rose’s research team dug up to 2.8 feet in depth and got “one core that goes back to 1895 and the other to 1760.”
Her conclusion that the water is getting worse is based on measuring levels of bacteria that were buried with the sediment.
“We also have actual monitoring data in one area from 60 years of data and it also shows deterioration,” Rose added.
E. coli is a bacteria used to set national and state health standards. Michigan counties have a long history of using the level of this bacterium as an indicator of beach water quality, said Sonia Joshi, the Ann Arbor-based outreach coordinator of Michigan Sea Grant.
But the method has deficiencies.
Measurement of E. coli usually takes 18 to 24 hours, which means the results can indicate only what the E. coli level was one day earlier. What’s more, considering E. coli is short-lived and its numbers fluctuate dramatically according to time and space, it is questionable whether the monitoring samples accurately represent the condition of a whole beach, according to both Rose and Joshi.
That’s why Ottawa County has stopped issuing closures and unsafe advisories, according to the county health department. People have to check water test results online themselves and decide whether to use a beach.
A more comprehensive and accurate way to monitor water quality is with a microbial source tracking tool, Rose said. It can find the sources of pollution by matching its DNA with the host of origin.
“Just like on CSI where they look for DNA at crime scenes, we can do the same thing in water,” she said.
Another problem with the traditional testing standard is its lack of indicators for non-swimming water recreation activities such as fishing and boating. For example, on Aug. 26, 2013, the E. coli bacteria level at Maplewood Park in Ottawa County was 4.75 times higher than the national standard, but the day’s monitoring survey shows there were six people fishing there.
Therefore, Rose said, determining the causes of illnesses from “partial body contact” water recreation is of great significance, and “that’s definitely an area of interest in the future.”
Despite all these findings, Kristina Wieghmink, Ottawa County Department of Public Health communications specialist, said water testing data has not deterred people from going to their beaches, and the county had good beach attendance in 2013.
The public can find information about nearshore water quality in different parts of the state through online testing systems. Two popular ones are the BeachGuard System established by the DEQ and the beaches location and rating map set up by the Natural Resources Defense Council.
Qing Zhang writes for Great Lakes Echo.
By QING ZHANG