Millions of acres of farm fields, city streets and wastewater treatment plants leach nutrients – in the form of nitrogen and phosphorous – into the Mississippi River. This “nutrient pollution” travels to the Gulf of Mexico from as far away as Wisconsin, contributing to a vast “Dead Zone” in the Gulf that is starved of oxygen. Illinois is one of 12 states tasked with reducing its contribution to the dead zone. In an interview, Brian Miller, the director of the Illinois-Indiana Sea Grant and of the Illinois Water Resources Center, explains how the newly released Illinois Nutrient Loss Reduction Strategy will work. News Bureau life sciences editor Diana Yates interviewed Miller about the plan.
How do nutrients in the water cause a dead zone?
Nutrients make algae grow. An overabundance of nutrients leads to too much algae in the Gulf of Mexico. When the algae die, the decomposition process steals oxygen from the water, making it hard for anything to live. There are hundreds of dead zones all over the world. The Gulf’s is the one of the largest.
What prompted the new plan?
The U.S. Environmental Protection Agency was very concerned about levels of nutrients from a 12-state area that were making their way to the Gulf and contributing to the dead zone. That zone continues to be large and in some seasons is actually getting larger.
An effective response requires that we all work together to reduce levels of nutrient runoff. To accomplish this, the EPA asked each of the 12 states to develop a nutrient loss reduction plan. In most states, that began with a scientific assessment of where most of the nutrients are coming from.
What are the biggest contributors to the problem?
In Illinois, we discovered that there are three main sources. One is agriculture. Another involves point sources such as wastewater treatment plants. The third is stormwater runoff from our lawns and streets.
We found that agriculture and point sources each cause about 48 percent of the total phosphorous pollution. Urban stormwater contributes about 2 percent.
In Illinois, agriculture is the largest source of nitrate, accounting for about 80 percent of the total. Another 18 percent comes from point sources, and the remaining 2 to 4 percent comes from urban stormwater.
What can be done to reduce farm runoff?
We need to separate the terms “runoff” and “nutrient losses.” The real question here is, “How do we reduce nutrient losses from farms?” Any time a storm event occurs, water leaves a farm. Water flowing into streams and rivers from farms, wastewater treatment plants or city streets is not a bad thing. The real issue is what’s in the water.
In Illinois, the problem isn’t necessarily the nutrients that you’re putting on your fields; it’s the nutrients that you lose from your fields. So what can reduce those losses?
Many agriculture producers in the state are considering practices aimed at reducing nutrient runoff. These include adjusting how much fertilizer they apply and when they apply it, adding cover crops to hold the soil and nutrients in place, rotating crops, and treating the rainwater runoff before it enters a ditch or stream. The agriculture groups are working hard to identify the most effective methods and encourage their members to apply those methods.
Aren’t farmers already doing this?
Some are voluntarily adopting some of these practices, but we’ll need a much bigger effort to reach the reduction target of 45 percent. The science assessment estimated that farmers will need to adopt at least one practice – over and above what they’re currently doing – on every acre, every year, to be able to meet this goal.
How is it that wastewater treatment facilities are still releasing nutrients into the environment?
The wastewater treatment process was originally designed to make sure that the water was cleaned up to the point that bodies of water would still be fishable, swimmable and drinkable. Most wastewater treatment plants were not originally designed to reduce nutrients at the level needed to meet newer goals. A lot of the newer facilities are adopting treatment technologies that reduce the levels of nutrients getting into lakes and streams.
What approaches will help these facilities reduce their contribution to the pollution?
There are a number of technologies that can remove some of the nutrients. Enhanced biological phosphorus removal, algal biomass treatment and denitrification all use biological processes to remove nutrients from water. The Metropolitan Water Reclamation District of Greater Chicago is currently studying these technologies at three of their plants, with promising results.
How does this plan differ from previous plans to reduce nutrient runoff?
One of the biggest differences this time is that a lot of stakeholder communities have come together to develop a strategy that is really going to reduce the amount of nutrients getting into our surface and groundwater. The Illinois Environmental Protection Agency, Department of Agriculture, IWRC and IISG worked with other government agencies, agricultural producers, commodity groups, non-profit organizations, scientists and wastewater treatment professionals on this plan.
When implemented, these recommended practices will improve local waters as well as the waters of the Gulf of Mexico. The real challenge now is putting the plan in place.