Federal environmental regulators this month released a report detailing options for combatting mercury contamination in fish in the Sudbury River, the first step toward making the fish safe to eat.

Meanwhile, a regional agency is readying a multimedia, grass-roots campaign to get the word out to fishermen along the river that consuming their catch poses grave health risks, especially to children. The campaign will include 30-second radio spots in Portuguese on Brazilian programs; website and print advertisements in English, Spanish, and Portuguese; and outreach to community groups and churches.

“The hazards of consuming the fish are not getting to everyone who needs to get the message,’’ said Martin Pillsbury, environmental division manager at the Metropolitan Area Planning Council, the agency that’s directing the campaign.

Starting in 1917, a 35-acre site in Ashland near the Sudbury River was used for industrial manufacturing, with Nyanza the most notable company to occupy the site. The companies produced textile dyes in a process that used mercury until Nyanza shut down in 1978, according to a federal Environmental Protection Agency report on the Superfund site.

During the site’s 61 years of use, vast volumes of chemical waste were buried in large pits underground, stored in lagoons, or discharged into the river via a small stream known as Chemical Brook. Cleanup at the industrial site has been ongoing since the 1980s, but nothing has addressed the mercury that flowed into the river, settled in its bottom sediment, and made its way into fish tissue, according to the report.

From 1940 to 1970 alone, approximately 51 metric tons of mercury were released into the river in Ashland, the report said. The Sudbury flows from its headwaters near the Westborough-Hopkinton line through Southborough before it passes the Nyanza site in Ashland, and then continues through Framingham, Wayland, Sudbury, and Lincoln before it reaches Concord, where it joins the Assabet to form the Concord River.

Ingesting mercury can cause significant neurological disabilities in cognitive thinking, memory, attention, language, and fine motor and visual spatial skills, according to the EPA. The effect is most profound on fetuses, infants, and children, since their nervous systems are still developing.

The report details several options for reducing risks of mercury poisoning, including public-awareness campaigns to stop people from eating its fish, capping tainted sediment, and a complex operation to dredge and clean sediment. The costs range from almost nothing to more than $200 million.

But there is no quick fix for a situation that’s been almost a century in the making, according to the report, which states that reducing the mercury in fish to acceptable levels could take decades.