To meet a court-ordered deadline, environmental regulators are racing to update mercury pollution limits in Oregon’s Willamette River Basin that may affect agricultural erosion rules.
Mercury is a neurotoxin that’s naturally found in soils but is also emitted by fossil fuel combustion and industrial processes. In Oregon, mercury from coal-burning power plants thousands of miles away in China, deposited through rain and dust, is also a significant source.
Agricultural practices are implicated as a source of mercury pollution due to the erosion of soils containing the element.
Currently, there’s a “minimal” amount of awareness among Oregon farmers about the link between erosion and mercury pollution, said Eric Horning, a farmer near Corvallis.
“It’s not a common topic of conversation,” Horning said. “There’s going to have to be an education process.”
Mercury may soon become a more relevant subject for growers in the Willamette River Basin due to upcoming regulatory decisions.
Last year, a federal judge ordered the region’s water quality standard for mercury — known as a total maximum daily load, or TMDL — to be revised by April 2017 due to an environmental lawsuit that faulted how the limit was calculated.
Oregon’s Department of Environmental Quality has now pulled together a committee, which includes representatives of the agriculture and timber industries, to advise on the revision process.
The state agency’s TMDL for mercury, which it’s updating with new data, is overseen the U.S. Environmental Protection Agency to ensure compliance with the Clean Water Act.
The Oregon Farm Bureau is troubled by the lack of input that DEQ is accepting about its estimates for the amount of mercury that’s deposited in the Willamette Valley and released into waterways.
Agriculture and other industries aren’t being given enough opportunity to review and weigh in on the agency’s assumptions about mercury sources, said Mary Anne Cooper, the organization’s public policy counsel and an advisory committee member.
Farmland is a major land use in the region, so it’s likely to be considered a “big player” in controlling mercury pollution, she said.
“I think this is probably going to be one of the most meaningful TMDLs for agriculture, certainly in recent memory or even ever,” Cooper said.
During a Feb. 15 meeting in Portland, DEQ officials told committee members their primary role was advising on how the TMDL will be implemented to reduce mercury levels.
The technical work of calculating the TMDL will mostly be decided by the DEQ and EPA due to time constraints, though the public will be able to comment on their findings, officials said.
However, assumptions about the sources of mercury are closely linked to the implementation of controls, since both involve crop types and farm practices, said Cooper.
Since sedimentation from farmland will likely be considered a significant source of mercury, the “fix” may involve a DEQ directive on managing soil erosion, she said.
Agricultural water quality regulations are overseen by the Oregon Department of Agriculture, but the concern is that DEQ may provide that agency with prescriptive instructions to reduce mercury pollution, Cooper said.
Such a directive could be burdensome for farmers and discourage innovation in erosion control, she said.
However, the ODA cannot realistically become much more drastic about controlling sediment, which is already a major focus of its agricultural water quality program, said Paul Measles, an agency hydrologist and committee member.
“The staff we have and the amount of places we can look at any one time isn’t going to change,” he said.
Erosion control in the region could be improved, but farmers are constrained by regulations in what they can do to reduce streamside sedimentation, said Horning, who is also a committee member.
Work to reduce bank erosion can be quickly performed with a front-end loader but generally requires cumbersome permitting from state and federal agencies, Horning said.
“It’s frowned upon and it shouldn’t be,” he said. “It should be embraced.”