Agency collaboration and researcher partnerships have been the keys to the success of the Harmful Algal Bloom Research Initiative (HABRI) since it began in 2015. With more than $7.5 million invested so far, and another $2 million awarded this year, the initiative aims to address Ohio’s harmful algal bloom problem, both in Lake Erie and in its watershed.
Fifty-four science teams at ten Ohio universities, funded by the Ohio Department of Higher Education, are on the case: working with front-line health, environmental and agricultural agencies, as well as water treatment plants and coastal communities, to bring them the answers they need to get the state – and region – ready to deal with HABs from all angles.
The third round of funded projects recently reported their final findings, and researchers are making promising progress on solutions for tracking blooms, protecting drinking water, reducing public health impacts and supporting sustainable agriculture efforts. Some of their results are presented here.
The full report will be available at go.osu.edu/habri.
Track Blooms from the Source
Modeling Manure Placement from Livestock Operations to Reduce Nutrient Runoff
Manure from concentrated animal feeding operations (CAFOs) is often used as fertilizer on agricultural fields. Transport from the manure lagoon to the fields is limited by permits, and more information is needed about the impacts of this manure fertilizer on the surrounding environment. This would help determine which fields in the Maumee River watershed are best suited to receiving this type of fertilizer.
Dr. Patrick Lawrence and his team at The University of Toledo are combining information from those state-issued permits on selected CAFOS with models of how manure is transported to get a better overall picture of where manure could be taken once it leaves the facility, where it is applied on fields, and where potential runoff during rainfall events may occur. This pilot project has potential to expand to other unpermitted livestock operations, including dairy and swine facilities, to better understand the total amount of manure from all CAFOs within the Maumee watershed and where application should occur to reduce possible impacts to water systems.
The overall aim of the project is to better inform farmers, management agencies and other stakeholders involved in CAFOs about how much manure is potentially applied on farmland in the Maumee watershed, and how that manure could affect the environment if it is applied in areas where flooding and runoff into streams, and eventually into Lake Erie, could be a concern.
Model data showed that the farmland that could receive manure from nearby livestock operations exceeds the supply of manure. In addition, 98 percent of the farmland under consideration was classified as having very low potential for nutrient runoff based on environmental conditions. The remaining 2 percent of farmland are found in two sub-basins of the Maumee watershed – the Upper Maumee and St. Joseph sub-basins – which could easily be targeted for best management practices that would reduce nutrient runoff.
Once the model is completed and validated, it will help with nutrient management in this largely agricultural watershed, which in turn could help reduce harmful algal blooms in Lake Erie that are fueled by nutrient runoff from the land.
Produce Safe Drinking Water
What Happens to Algal Toxins in Water Treatment Residuals?
Drinking water treatment residuals (WTR), the solids left behind once water is treated, have beneficial uses. Water-softening WTR are a high-quality lime material that is often applied on farmland to create optimum soil pH for crop production. Alum or Ferric WTR has been used as topsoil replacement or in soil blends. Beneficial use of WTR directs residuals away from landfills, saving communities money and benefiting farmers.
However, recent Ohio EPA monitoring found that algal toxins like microcystin were present in some residuals from water treatment plants that are affected by harmful algal blooms. Because toxins in the soil have the potential to be absorbed into growing crops, use of these residuals needs to be evaluated.
Currently, water treatment residuals are not routinely tested for microcystin to determine whether they would be suitable for soil replacement. Dr. Nicholas Basta and his team at The Ohio State University are now beginning to develop testing guidelines for residuals, from how best to extract them at the treatment plant to what happens once they are placed on the land.
Specifically, the researchers are optimizing analytical laboratory methods to measure microcystin in the residuals, studying the uptake of microcystin by plants grown in soil that contains residuals, and measuring the persistence of microcystin in soil blends that contain residuals.
Preliminary findings show that microcystin is indeed present in water treatment residuals collected for the project. Test crops like carrots and soybeans also did take up microcystin when grown in soil that contains residuals. In carrots, the majority of accumulated microcystin was found in parts not usually eaten, lowering the estimated health risk associated with consumption.
However, both carrots and soybeans grown in soil containing WTR showed stress responses like stunted growth and yellowing of the leaves, potentially impacting agricultural yield and sale value at larger scales.
Protect Public Health
Preventing Negative Effects of Algal Toxins in Patients with Liver Disease
Algal toxins like microcystin affect the liver, but studies on specific health effects have been limited to healthy participants and not focused on actual treatment. However, about 30 percent of the population has some form of liver disease, which could be exacerbated by exposure to microcystin.
Dr. David Kennedy at The University of Toledo is conducting research on the impacts of algal toxins on people with non-alcoholic fatty liver disease, one of the most common forms of pre-existing liver disease, and testing new therapies to prevent or mitigate the damage these algal toxins can cause.
The research team is using mice bred to exhibit pre-existing liver disease and testing the effects of chronic microcystin exposure at levels well below those established as safe by the World Health Organization. They are also adding two different methods to block the inflammation and oxidative stress on liver cells that microcystin causes, including the use of a new laboratory-developed peptide. Peptides are small chains of amino acids, which in turn form the basis for larger protein molecules.
When completed, the project aims to define new guidelines for safe microcystin exposure in patients with pre-existing liver conditions. The researchers also hope to develop new tests that can measure toxin exposure at very low levels, as current tests are often unable to detect the specific damage microcystin causes. To date, they have developed a new mass spectrometry method to identify different variations of microcystin from blood and urine samples.
Studies of the inhibitor compounds used in this project indicate that there may be less damage from oxidative stress on mice treated with the lab-developed peptide. Those results may form the foundation for future research into developing a clinical treatment for the negative effects of microcystin on liver cells.
Storage and Treatment of Manure Can Impact Phosphorus Loss from Fertilized Fields
Using manure as fertilizer on agricultural fields is a common practice, but has the potential to contribute to harmful algal blooms in Lake Erie and other Ohio lakes. These occasionally toxic blooms can cause health problems and negatively impact fishing and tourism, making them a concern for many state agencies and local communities.
Previous research suggests that changes in manure storage on the farm, before it is applied to fields, affect how much of the nutrient phosphorus can dissolve out of the manure and run off the field unused. Dr. Harold Keener and his team at The Ohio State University are now working to determine specific management practices that reduce this potential nutrient runoff, ranging from analyzing current manure characteristics at Ohio dairy, swine and poultry farms to modeling the impacts of suggested changes in manure storage and timing of application on phosphorus runoff.
They studied the effect of storage conditions on phosphorus in liquid dairy and swine manure, as well as in solid poultry manure, and found that total phosphorus content in their samples decreased significantly from 2005/2006 to 2018, possibly due to changes in animal feed, and that phosphorus concentrations are higher in the solid portion once manure is separated into liquids and solids.
They also found that long-term storage is beneficial in a number of ways, including a significant reduction in soluble phosphorus in swine and dairy manure. High storage temperatures generally seem to help with phosphorus reduction as well. Results overall showed that long-term storage of 180 days or more is good practice, both reducing the potential for phosphorus runoff and making the timing of manure application more flexible.
Based on these findings, the scientists will work with farmers to present their data and evaluate how willing farmers would be to adopt new manure management practices. Educational materials such as fact sheets and articles will also be developed to provide guidelines on best practices for manure storage that maintain its use as fertilizer while helping to protect Lake Erie from harmful algal blooms.