COLUMBUS, Ohio — Toledo residents were without drinking water for three days when a harmful algal bloom (HAB) on Lake Erie may have caused a reading of 0.6 microcystins in the city’s drinking water. These are toxins which may pose a risk to human and animal health.
Farmers are definitely taking some heat. "Fertilizer sales are decreasing and people are getting smarter about what they are putting on the fields," said Adam Rissien, agricultural and water policy director of the Ohio Environmental Council. "Many producers are enrolled in conservation programs. Farmers are wondering, ‘What is going on; why isn’t this working?’"
Yet, not all farmers are enrolled in these programs and not everyone uses best management practices (BMPs), Rissien said. Scientists aren’t sure if "it isn’t working" because there is not a broader adoption of these practices or if it’s because the practices aren’t effective.
But there are things that need to be done. The phosphorous applied needs to be applied directly into the soil, not broadcast, he said. Scientists also think manure is a source of phosphorous loading and that Ohio needs to end the practice of allowing people to spread manure in the winter on frozen and snow-covered ground.
Also, the state has a loophole that gets around the requirement for Confined Animal Feeding Operations (CAFOs) to develop nutrient management plans, Rissien said.
CAFOs can sell or give away their excess manure in lieu of developing these plans. Another thing that needs to be remedied, Rissien said, is that a farmer does not have to be certified to apply fewer than 4,500 tons or 25 million gallons.
Finally, a recommendation in the Lake Erie Ecosystem Report was to have the U.S. EPA and its Canadian counterpart establish daily limits on the amount of phosphorous allowed in streams and waterways throughout the entire Western Lake Erie Basin, something like a Total Maximum Daily Load (TMDL).
"We believe that because agriculture is exempted from the Clean Water Act, that is an opportunity for further regulation," Rissien said. "We don’t think that voluntary practices are going to solve the problem."
Most farmers are using voluntary practices and doing their best to be good stewards of the land, said Justin Chaffin, research coordinator at Stone Laboratory of The Ohio State University. Stone Lab scientists think possibly the massive 2011 bloom that covered the Western Basin could have somehow reset the system to a stage where the microcystis needs less phosphorous to get going.
"We had this big bloom in 2011 and a small bloom in 2012," Chaffin explained. "We do see that in 2012 there was a drought and there was a lot less phosphorous that got in; so we know if we cut down phosphorous loads, the lake will improve pretty quickly. It is a matter of keeping the phosphorous on the land when we have wet years."
HABs have become a global problem. In Lake Erie, scientists are fairly confident the spikes in phosphorous after rain is mostly because of agriculture. Lakes in China that are surrounded by millions of people have the problem due to lack of sewage treatment.
"Lakes like Grand Lake Saint Marys, where they have a lot of livestock in the watershed, the source of their problem is animal manure," Chaffin said. "If you have a bloom on a golf course, their source of their problem would be lawn fertilizer. This is a global problem and the source of the problem is likely due to what is around the watershed."
It is likely conditions in the lake that led to this event will occur again this year and in future years until phosphorous loading is reduced by at least 40 percent, said Ohio Sea Grant and Stone Lab Director Dr. Jeff Reutter, in a fact sheet put out by the lab.
"However, modification of operating procedures at water plants make it much less likely that a drinking water ban would be necessary," Reutter added.