Agriculture seen as the main culprit in Great Lakes phosphorus pollution

Sunday, October 5, 2014

A new report says that, while phosphorus is coming from a variety of sources, the bulk of it results from agricultural runoff, with municipal sewage discharges a distant second

by DON STONEMAN

Authorities and environmental groups are pointing a finger at agriculture as a major contributor of phosphorus to the Great Lakes, and a massive summer algae bloom in Lake Erie, even as the role of municipal sewage is downplayed.

"Runoff from agricultural land in the watershed in both the United States and Canada is the largest non-point source of phosphorus entering Lake Erie today," says a report released by Toronto-based Environmental Defence in August. Non-point source pollution comes from diffused sources, and the environmental organization claims it is a more important source of pollution in Lake Erie than is anything from sewage treatment plants.

"We absolutely recognize that the phosphorus is coming from a variety of sources, both rural and urban. The research is showing that the majority of nutrient pollution is coming from agricultural runoff," Nancy Goucher, Environmental Defence's water program manager, told Better Farming. "Even if we completely stopped nutrient pollution from urban areas, we would still see blankets of algae covering the lakes until we find ways to help farmers reduce their runoff."

Algae blooms threaten public health because water isn't safe to swim in. They lower the value of waterfront properties, damage the tourism industry and kill fish. And, in a famous case earlier in the summer, they clogged water intakes. Residents of the city of Toledo were forced to drink bottled water for two weeks.

According to Environmental Defence, normal sewage discharges account for only 16 per cent of the phosphorus inputs into Lake Erie. The report notes, however, that "heavy rains, increasing in frequency" bypass municipal wastewater treatment plants and "can significantly increase phosphorus loadings from urban sources."

In 2013, the city of Windsor's pollution control systems were bypassed 49 times as storm events and meltwater overcame the city's sewage system. The town of Amherstburg, downstream on the Detroit River, suffered through the same experience 20 times. The town of Leamington, also in Essex County, reported 26 bypasses to the Ontario Ministry of the Environment's Spills Action Centre (see chart on the Better Farming website at www.betterfarming.com).

A February report from the International Joint Commission (IJC) on the Great Lakes points to investments in sewage treatment plants in the 1970s. Along with regulations on detergents, phosphorus loading in Lake Erie was reduced by more than 50 per cent. But the problem of algae is growing again. "While sewage plants still contribute some phosphorus to Lake Erie, diffuse runoff from rural and urban lands is a leading factor in eutrophication. Of particular concern is runoff of dissolved reactive phosphorus, the portion of total phosphorus that is most readily available to support algae growth and thus a primary cause of renewed algal blooms. Addressing runoff requires strategies tailored to particular land uses, rather than controls on sewage plants alone," says the IJC report. Fertilizer and manure applications are blamed. Losses occur during snow melt and spring. The Maumee River in Ohio is the single largest source of dissolved reactive phosphorus generating harmful algae blooms in Lake Erie.

Environmental Defence announced a four-point plan in August to help farmers deal with the issue via the market rather than by regulation, calling for the province to "evaluate the applicability of market mechanisms such as tax-shifting, pollution taxes, and nutrient trading to transfer money from undesirable acts like polluting to desirable ones that reward farmers for doing the right thing."

Goucher says release of Environmental Defence's four-point plan drew attention from both federal and provincial governments, but no meetings had taken place as of early September. She says tax-shifting means that there would be a tax on activities that were damaging to the environment, while farmers were rewarded, by a tax break, for doing things that have a positive environmental effect.

But, notes Jacqui Laporte, environmental specialist, innovation, engineering and program delivery, with the Ontario agriculture ministry, "some of the things that Environmental Defence suggests are not the way our grant programs work." Under the federal government's Growing Forward 2 program, "we pay people to build manure storages or we pay people to put in a vegetative buffer." The Environmental Defence scheme, she says, "is looking at an economic solution as opposed to a Best Management Practices (BMP) solution."

Economics drive farm decisions, Forbes agrees, stressing that different BMPs work at different times of the year and in different locations.

Traditionally, the provincial agriculture ministry uses things like the Environmental Farm Plan or straight-up government subsidies. Goucher says that's not working. "Our conclusion in our report is that this status quo is not doing enough. We are seeing some progress made . . . but we are still seeing algae blooms increase in size and frequency and we are not doing enough and we need to find ways of scaling up these projects so that we are not seeing algae blanketing the Great Lakes every summer." BF