The Maryland Department of the Environment has sent 60 metal warning signs to Baltimore County to advise people to avoid or limit the amount of fish they eat from some county waterways because of contamination from substances such as mercury, PCBs, and pesticides.

The state environmental department has long provided these advisories as laminated, paper signs to be posted near affected areas, said spokesman Jay Apperson, but they were always either removed or damaged.

Baltimore County received signs in English and Spanish — 30 of each, meaning they can place signs in both languages at 30 locations. The county has tentatively identified 20 locations for signage, county spokesman Sean Naron said. They’re assessing which sites would be good locations for the sign installation beginning in early spring 2020, he said.

Naron said the county picked locations based on a review of potential fishing sites at county parks that correlated with the consumption advisories. The majority of the locations so far are in eastern Baltimore County’s Dundalk, Sparrows Point and Edgemere areas. The state recently provided metal signs to Prince George’s County for use on the Anacostia River.

Consumption advisories are issued when an analysis of fish tissue reveals “environmental factors that have the potential to increase health risks,” Apperson said in an email. The state environment department has worked to make information on these advisories more widely known and accessible, he added.

Polychlorinated biphenyls, or PCBs, and mercury can remain embedded in sediments for decades, and the contamination spreads up the food chain. The level of toxicity in different species depends on how much of their lives, or the lives of their prey, are spent in contaminated waterways. Migratory fish can accumulate lower levels of contamination, for example, whereas bottom feeders can contain the highest levels because of constant exposure.

PCBs have been shown to cause cancer and harm the immune, reproductive, nervous and endocrine systems. Mercury poisoning can cause brain damage that reduces hearing and vision, changes personality, and triggers memory problems, seizures or paralysis, as well as developmental problems in children.

The advisory says people should avoid eating the catfish, eel and blue crab “mustard” — part of the crab’s digestive system — from the Middle River, Patapsco River and Baltimore Harbor. It also provides recommendations for other fish species and county waterways, as well as consumption guidelines for children under seven, women who are nursing, pregnant or may become pregnant. The full advisory is online.

Alice Volpitta, lead water quality scientist for Blue Water Baltimore, said she was glad to see an increased effort to educate the public on the public health risks associated with pollution, because in many areas, people wade or fish in areas without knowledge they could be exposing themselves to illness. The local water quality advocacy group has been pushing for more signs around the Inner Harbor, for example, where there are often high levels of fecal bacteria, and Volpitta said she isn’t aware of any signs around Baltimore about mercury or PCBs.

While the new signs around Baltimore County will help change that, she added, she hopes it doesn’t scare people off from fishing or boating entirely.

“We’re always in favor of people having more information,” she said. “I think posting signs is a good step. Hopefully it won’t keep people from actively participating in their waterways.”

County Councilwoman Cathy Bevins, who represents communities along three waterways, said fellow Democratic County Executive Johnny Olszewski Jr. should request more signage from the environment department.

“This is worrisome,” said Bevins of Middle River. It’s “alarming” because people use those waters to either swim or fish for food, including some restaurants, she said. “People are out there all the time, sitting on their buckets and catching catfish and taking them home to eat them.”

Republican County Councilman David Marks agrees with Bevins. Like Bevins, Marks also represents communities along Bird River.

“It’s extraordinarily concerning. Baltimore County’s waters are among our most important resource — not just for fishing, but also for recreation,” Marks of Perry Hall said.

The joint effort to advise residents comes after County Council voted in October to have the county ask a federal judge to force agriculture chemical company Monsanto to pay for the cleanup of environmental toxins submerged in the county’s water bodies. The county, and Baltimore City earlier this year, allege Monsanto was responsible for the PCB production and was “long aware” of its harmful nature.

A spokesman for Bayer, which completed its takeover of Monsanto last year, told The Sun the former company voluntarily stopped producing PCBs more than 40 years ago.

While some signs around the region mark waterways that are unsafe for human contact because of sewage contamination, water quality advocates said there is little public information or knowledge about the harms of industrial pollution. David Sikorski, executive director of the Maryland chapter of the Coastal Conservation Association, said he recalled state environmental officials giving out pamphlets or fliers about fish contamination in years past, but not anytime recently.

“There’s very little awareness,” said Sikorski, whose group that represents recreational anglers. Information about fish and shellfish contamination is “something that continuously needs to be provided for the public,” he said.