I imagine that most people have positive associations with the word "nutrient," and in my years as a physician, I did, too. After all, nutrients, like protein and vitamin A, are the cornerstone of human nutrition. But when we talk about the Chesapeake Bay, or any body of water, the word takes on another meaning entirely.
In the bay, nutrients like nitrogen and phosphorus are major culprits in the pollution that creates dead zones, algal blooms, and higher levels of bacteria that are harmful to people. And lately there's been quite a bit of attention paid to an Environmental Protection Agency proposal that Maryland adopt a "nutrient trading" program as a solution to nutrient pollution in the bay.
Under this program, entities that release nutrients to the bay would be able to generate "credits" by reducing their discharges below what the law requires. They could sell these credits to other sources that would purchase them in place of reducing their own releases.
In a perfect world, nutrient trading would reduce pollution while providing flexibility to governments and businesses. Unfortunately, our world is far from perfect, and nutrient trading is riddled with problems.
My first objection to this kind of program is semantics. Let's call it what it is: pollution trading. Excess nutrient pollutants in the bay lead to public health problems, just as other pollutants do. Human exposure to nitrites from excess nitrogen in drinking water can lead to "blue baby syndrome," which can cause illness and death in babies and has been related to spontaneous abortions and increased cancer risk.
Elevated nutrient levels can also lead to the proliferation of harmful algae and pathogenic microorganisms like Vibrio bacteria, cryptosporidium and giardia. Infection by these microbes can lead to gastrointestinal illness and severe diarrhea.
Who's discharging these pollutants into the water? Some are energy companies, some are factories and some are wastewater treatment plants. In Maryland, however, agriculture accounts for 37 percent of the nitrogen and 48 percent of the phosphorus released into the bay.
Most nutrient output from agriculture comes from animal waste. In 2011, Maryland produced more than 311 million chickens — and that means lots of chicken manure and lots of nutrients.
The vast majority of Maryland chickens are produced at mammoth "concentrated animal feeding operations" (CAFOs) on the Delmarva Peninsula. Exactly how CAFOs might participate in nutrient trading remains rather murky; the rules have not been written yet. Different scenarios are possible, and each is troubling.
Under the Clean Water Act, CAFOs may not release nutrients or other pollutants into the bay or its tributaries. If CAFOs comply with the law, as they always claim they do, CAFOs should not be able to generate credits. After all, they cannot reduce their pollution to less than nothing.
If they are not in compliance, as numerous studies suggest, then they should not be paid for violating the law. The better approach is more active enforcement by the EPA and state government, which should tell industries to straighten up and fly right. The Clean Water Act is an example of a tried-and-true regulatory strategy. Old-fashioned? Perhaps. Proven effective when enforced? Definitely.
Perhaps CAFOs will not be allowed to participate in nutrient trading. That would make the most sense. On the other hand, it would mean that the centerpiece of bay restoration efforts (nutrient trading) does nothing to address a primary source of the bay's problems.
Regardless of CAFOs' involvement, allowing industries to buy credits rather than reduce releases could result in local "hotspots" of pollution in areas dominated by these industries. Most likely, these hotspots would appear in low-income communities, where residents don't have the means to move or to fight the stockpiling of pollution in their backyards.
Nutrients and other agricultural pollutants pose a serious public health problem. A nutrient trading (or pollution trading) scheme is not an effective response. Policymakers should instead focus their energy on better enforcement of existing regulations that address the discharge of waste into our bay.
Dr. Robert S. Lawrence (firstname.lastname@example.org) is the director of the Johns Hopkins Center for a Livable Future at the Johns Hopkins Bloomberg School of Public Health.