Most fish in the United States contain mercury, but states rarely explain the health dangers to immigrants and low-income people who often rely on catching fish for their daily meals.

Studies show up to 10 percent of women of child-bearing age have mercury levels that exceed federal standards. The substance, which occurs naturally in fish and is exacerbated by power plant pollution, can be devastating for the neurological development of children.

Despite the danger, states usually only post advisories on websites. Many immigrants are unaware that adults should eat only one serving a week of some species and children and pregnant women should eat less.

Some officials say immigrants and other regular anglers could make better choices if the government did more to communicate the guidelines.