A pair of kayakers enjoy a paddle in the waters off the city of Marquette. (Journal file photo)

MARQUETTE — When even the slightest amount of mercury enters a fish’s body, it can begin a long cycle that ends in disaster for aquatic wildlife and health concerns for humans, experts say.

That’s because mercury, an element often produced as a byproduct of mining and fossil fuel production, never breaks down or leaves an organism’s body. Instead, it continues to be passed along as animals eat and get eaten.

“The material concentrates even more,” said Megan Tinsley, the water policy director at the Michigan Environmental Council. “As it moves up the food chain, you can have organisms holding higher and higher levels of those chemicals.”

That results in mercury-contaminated wildlife and do-not-eat advisories for humans.

Although mercury is especially infamous for being passed along the food chain, it isn’t the only toxic chemical that triggers that process — something scientists call bioaccumulation.

It’s one of 22 chemicals that the Department of Environment, Great Lakes and Energy, or EGLE, recognizes as “bioaccumulative chemicals of concern,” or BCCs. Other chemicals include a form of the once-popular insecticide DDT and polychlorinated biphenyls, or PCBs, a compound that was used in manufacturing and has been linked to cancer.

Many of those chemicals pollute the environment through run-off or chemical leaks, said Kevin Cox, the department’s water toxics unit supervisor..

“The presence of these chemicals in the environment can impact the health of both aquatic organisms as well as humans who become exposed through consuming fish or ingesting contaminated surface waters,” Cox said.

But the department’s current list of bioaccumulative chemicals — which Tinsley says is crucial to public understanding of which substances are especially harmful to human health — hasn’t been updated in nearly 20 years, despite updated science.

That’s because EGLE legally can’t make additional rules on water quality regulation. A provision in the state’s Natural Resources and Environmental Protection Act prohibits the department from issuing additional water regulation rules after Dec. 31, 2006.

Cox says new chemicals of concern could still fall under the department’s definition of bioaccumulative chemicals, even if they aren’t on the official list.

One such chemical is perfluorooctane sulfonate, or PFOS, which Cox said was commonly used in fire-fighting foams. The Centers for Disease Control and Prevention says PFOS can increase cholesterol and lower antibody response to certain vaccines.

It isn’t on the department’s list of chemicals of concern. But since it has a bioaccumulation factor that meets the department’s broad definition of what a BCC is, EGLE is allowed to regulate PFOS as it would any other such chemical, Cox said.

Environmental activists aren’t convinced.

“The state agency in charge of protecting water should be able to classify something as what it really is,” Tinsley said. “We need to be looking at updated science and having the ability to include things that are emerging.”

The outdated list of toxic chemicals is just one consequence of EGLE’s lack of full rulemaking authority, Tinsley said.

“The department as a whole has been prevented from doing much work at all for a long time,” said Sen. Rosemary Bayer, D-West Bloomfield.

Bayer and Sen. Sue Shink, D-Northfield Township, say they hope to change that with their bill to empower EGLE to regulate water. It passed the Senate Energy and Environment Committee on March 7.

Bayer said Republican lawmakers were “driven by corporate interests” when the Legislature first set the limitations years ago, something she’s still trying to undo.

“They went into the different parts of the code and took away their ability to create rules,” Bayer said. “And we’re just going through, one at a time, and fixing them.”

Bayer and Shink’s efforts have been met with resistance.

Ben Tirrell, the associate legislative counsel at the Michigan Farm Bureau, said the bill and a similar one would give EGLE too much power.

Tirrell said the Farm Bureau opposes the legislation based on the organization’s support for transparency, “as well as the economic and scientific review of rules and standards.”

“Transferring this expansive authority to EGLE threatens these values, while the Legislature has and can continue to address water quality effectively and remains the appropriate forum for these important policy decisions,” he said.