Gone Fishing, But Can You Eat the Fish?

BY ON August 19, 2015

Cartoon with fish saying "you can't eat me I'm polluted"


There’s nothing like the thrill of seeing your bobber dip underwater and feeling a tug at the end of your fishing line. Growing up in Massachusetts, both my sons loved fishing on nearby lakes and rivers. Rarely did a fish come home with them. The ones they managed to catch were either too small, or were quickly released by their soft-hearted captors.

Perhaps that’s just as well.

The New England Center for Investigative Reporting (NCIR) reports,

“Mercury emissions from major sources in Massachusetts have declined by 90 percent over the past two decades, but mercury levels in the state’s freshwater fish hold stubbornly high, with many species too contaminated for pregnant women and children to eat.”

A sign posted next to the Sudbury River in Concord, Mass. where I  walk my dog, attests to this danger in three languages. In fact, many of the state’s waterways have such signs, but even ones that do not may contain fish with mercury levels above EPA standards.

That is despite the fact that the Massachusetts Department of Environmental Protection (DEP) has taken several steps  to control mercury, including air emission controls for coal-fired power plants, and specific mercury air emission limits for municipal waste combustors. The state encourages mercury recovery and control of emissions within the environment through its Mercury Management Act, which requires recycling of certain items, and bans certain products. Dentists who use mercury amalgam, for example, must certify the efficacy of their mercury separators.

Why do our fish still contain dangerous amounts of mercury?

Climate change is one factor, yet it remains a conundrum with no easy answers.

To learn more, I reached out to officials at the Massachusetts Department of Environmental Protection. Three of them got together and answered my questions in a recent phone call.

They noted that research by the state’s office of research and standards has shown that since standards have been established, there has been a dramatic reduction of mercury found in fish living in water bodies near coal-fired power plants, for example. But, as one official pointed out,

“Air doesn’t respect boundaries. Mercury from coal producing plants around the world can end up here. Air disposition of mercury is a pretty important source. We’ve worked hard in Massachusetts to control the worst local sources, but what is needed is more action at the national and global level to reduce the mercury in the air. Until that’s done, there will be a real limit to what we can do locally.”

They also explained that while mercury emitted in the Midwest or even Asia can settle in Massachusetts, there are also some site-specific causes for mercury-laden fish.

Each waterway is different, and a pond’s particular biological and geological characteristics will determine how much mercury is present in the tissue of the fish that reside there. Even in waterways with similar levels of mercury, the levels in their fish will differ depending upon factors such as PH level and the amount of organic material. As the officials noted,

“It’s quite site specific. There are complicated interactions between chemistry and biology within each pond. A pond that has a lot of organic material might bind with mercury making less of it available to the fish.”

Sign_smallWhat’s a concerned citizen to do?

  • Massachusetts residents can check the status of their local ponds and other freshwater waterways by consulting a chart on the Massachusetts Department of Public Health web site. When I consulted the database I learned that the sign I saw by the Sudbury River should be taken quite seriously — fish caught in the Sudbury River contain so much mercury, they should not be eaten by anyone.
  • The officials I spoke to encourage people to talk to their state and federal representatives, as many of us did  at the recent Play-In for Climate Action and, they said, “…urge them to make sure that the programs that are in place stay in place and that there’s more action on a broader, national level.”




TOPICS: Food, Massachusetts, Mercury Poisoning