A state judge has approved controversial changes to the water quality standards protecting nearly every lake, stream and wetland across Minnesota.

The revisions by the Minnesota Pollution Control Agency (MPCA) target nearly a dozen pollutants — chloride, salts, sulfate, nitrate and more — in surface water used for industry and agriculture, and for wildlife. All waters in the state are protected for such uses.

Administrative Law Judge Eric Lipman on Friday recommended the MPCA adopt the changes, agreeing that they will help the agency "develop a sturdier set of regulatory standards that will be more defensible when challenged."

The MPCA characterized the revisions as a "touch-up" to outdated science on protecting surface waters, resulting in more flexible permits tailored to individual dischargers.

But Lipman made his decision over the strong opposition of several Native American tribes and environmental groups. They said the MPCA is putting the needs of permit holders and industry ahead of the environment.

The changes affect scores of large permitted water dischargers in Minnesota. They include municipal wastewater treatment plants, food processors and taconite mining companies, for example, that pump effluent into the environment.

The MPCA has maintained that the changes will not have a significant negative impact on the environment. Federal law requires the agency to periodically review the standards.

In a statement, the MPCA said it is pleased with the changes and will submit them to the U.S. Environmental Protection Agency for final approval.

"The agency has consistently said Minnesota can protect its waters while lowering regulatory hurdles by using the latest science as a guide," it said.

A key issue is that the revisions remove many concrete numeric standards for contaminants, replacing them with a narrative description of what should be accomplished or avoided. The narratives will require a complicated "translator" to convert the language into enforceable limits.

Cities, mining companies and other discharge permit holders have pushed for such changes for years in an effort to reduce the cost and burden of compliance. They say that existing standards force them to pay for unwarranted, expensive pollution treatment.

U.S. Steel Corp., owner of Minntac, the state's largest taconite mine, sued the MPCA in 2017 for failing to complete the revisions before the agency reissued its draft water pollution permit.

Tribal and environmental opponents said the revisions significantly weaken protections and give polluters a free pass, threatening small-scale and organic farmers growing vegetables and fruit, for example, as well as wildlife.

At a public hearing in February, April McCormick, secretary-treasurer of the Grand Portage Band of Lake Superior Chippewa, testified on behalf of a coalition of 10 Minnesota tribes. Best practices call for concrete numeric standards, she said, adding that narrative standards aren't progress but "outdated and underprotective."

"They benefit no one but large industrial dischargers who seek to avoid regulation," McCormick told the judge.

For water used for industrial purposes, the changes remove specific numeric standards for pH, chloride and hardness and replace them with a narrative description.

For water used in irrigating crops, for livestock and by wildlife, the changes remove most numeric standards for salts and other pollutants and replace them with a narrative or less stringent standard.

Finally, the revisions add two new numeric standards for water used by wildlife: sulfate at 600 milligrams per liter and nitrate at 100 milligrams per liter. Both are significantly higher than other existing standards for those pollutants.

Minnesota has a 10 milligram per liter sulfate standard for protecting wild rice — a standard the MPCA has said is not affected by the changes.

Paula Maccabee, counsel for the nonprofit WaterLegacy, said both of the new numeric limits are far too high. They undermine the state's ongoing efforts to reduce nitrate pollution, she said.

The MPCA is revising the standards for Class 2 waters for aquatic life and recreation. On Friday, WaterLegacy submitted a petition to the agency with nearly 500 signatures urging it to toughen those rules.

"We're going to do everything we can … to make sure the regulatory agencies change course and begin protecting people and clean water, instead of protecting dischargers of pollution," Maccabee said.

Jennifer Bjorhus • 612-673-4683