Sally Brown's Research Commentary - September 2014
Thirsty in Toledo
Just a few weeks ago, residents of Toledo, OH were told to turn off their taps. Their drinking water, sourced from Lake Erie had concentrations of microcystin, a toxin produced by algae following an algal bloom in a portion of the Lake that were above regulatory limits. Everyone agreed that the algal bloom was caused by excess phosphorus. What everyone didn’t agree on was the source of the phosphorus. Wastewater treatment plants were often mentioned in the news reports during and after the ban, but the science points to non-point sources as the primary culprit. This month’s library is devoted to non-point source water pollution, the thing that the Clean Water Act didn’t have the courage to tackle and the major factor behind the continued pollution of our nation’s waterways. I focused on this, rather than the traditional biosolids related themes, so that the people that use the library would have information to share with the public and the press when the next algal bloom occurs and fingers start pointing in the wrong direction.
The first article in the library is a report by Ohio EPA on the excess nutrients in Lake Erie. This report was the product of a large group that included Nick Basta from Ohio State University who is one of the key scientists working on biosolids. It is a very thorough report including a discussion on the chemistry of phosphorus. If you look at the discussion section starting on page 73 you can read some key points. First is that “point source loadings are not a major contributor to the increase in DRP (dissolved reactive phosphorus).” Second is that “while there are multiple contributors to phosphorus loading, currently the most significant is the result of runoff from agricultural nutrient applications.”
The second article is an early feature article focused on tracing the sources of nutrient water pollution. It is a feature article, which means that you might not fall asleep while trying to read it. It also has some really nice graphics. These include maps of the US showing the nitrogen and phosphorus inputs from fertilizer use and animal manure. No surprise here, as both are significantly greater than from point sources in urban areas (shown in figure 5 of this article). So two credible sources, confirming that it is fertilizer and manure use from non-point sources that were the primary culprits for water quality degradation in the 1990s through the present. Why hasn’t anything been done?
For that we go to the third article. It is all about the economics, or at least that is the common argument. This article is actually a report from USDA’s Economic Research Service about the challenges of designing programs to limit non-point source pollution with a focus on the economics and barriers to change. The authors note in their abstract that the information needed to design economically efficient tools here is lacking. So, instead they focus on appropriate policies to reach these environmental goals at the lowest cost (not clear what the real difference is) The paper outlines costs associated with five options that can be used to reduce non-point source pollution: economic incentives, standards, education, liability and research. Just saying here, that liability and the potential for NPDES violations have worked well in the municipal sector.
The last two papers are new ones. The first focuses on phosphorus and water budgets in South Florida, near the Everglades where excess P has been a huge issue. Again, agricultural producers are identified as major sources of excess phosphorus. Seasonal variation is noted and different farms are classified as high or low impact to water quality.
The final paper is a very short policy oriented paper. It focuses on the importance of watershed phosphorus management strategies. Phosphorus loadings from the legacy of excess P use are noted. The authors talk about coming into an appropriate P balance for watersheds where excess is not added and drawdown of P is in equilibrium with inputs. They take the balance sheet developed in the 4th paper and apply it to minimize environmental impact.
So, when the next crisis happens and fingers start to point, you’ll be well equipped to show them what direction to point towards. Perhaps some time in the near future, the powers-that-be will realize that those successes realized when point sources of excess nutrients were controlled (that would be us WWT folks) provide a blue print for what needs to be done for the non-point sources.
Here are a variety of papers which don't fall into a specific category. Some of the work is on greenhouse gas emissions, public perception or biosolids management strategies.
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