By Qing Zhang
Great Lakes Echo
Michigan has more than 1,200 public and nearly 500 private beaches.
Closing them or issuing safety advisories due to pollution 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.
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 bacteria levels which were buried with the sediment.
“We also have actually 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 Grant Sea.
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 out the sources of pollution by matching its DNA information 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, Ottawa County Department of Public Health communication specialist Kristina Wieghmink said she didn’t see the water testing data has deterred people from going to county 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.