2004 U.S. SJWP Winners' Abstracts

Brandon Fimple
2004 U.S. Stockholm Junior Water Prize Winner

Project Title: The Environmental Impact of Aluminum Sulfate and Salicylic Acid Treated Poultry Litters on Forage Production and Watersheds


Eutrophication resulting from phosphate pollution is one of the most costly water quality problems in North America today. Algae overgrowth not only affects drinking water quality, but biologists recently discovered that chemicals released by some algae stimulate the reproduction of zebra mussels. Agricultural practices contribute much of the non-point sources of nitrate and phosphate pollution in surface and ground waters. Research to develop ways of reducing phosphate pollution in watersheds is vital due to the increasing number of confined animal feeding operations as market animal production is fast becoming a corporate farm venture. Large concentrations of animals produce large quantities of animal waste that must be disposed of properly to prevent nutrient pollution in surrounding watersheds.

This experiment combined three years of research on allelochemicals with last year’s study of alum treated poultry litter in an effort to find an environmentally protective litter treatment with effective algaecide properties. Salicylic acid (SA), an allelochemical found in the roots of birch trees, has been shown to be a very effective algaecide when added directly to poultry litter run-off water. The purpose of this experiment was to evaluate the effects of poultry litter fertilizer treated with salicylic acid on forage production and run-off water phosphate levels and to determine if Closterium algae growth in the run-off water was adversely affected. Aluminum sulfate (alum) has been used successfully as a litter treatment, but its effects on forage production in phosphorus deficient soil has not been evaluated. Therefore, alum was tested in this experiment also.

Five poultry litter treatments – 10% and 5% salicylic acid, 10% and 5% alum, and plain litter - were tested in each phase of the experiment. It was hypothesized that the salicylic acid and alum litters would not adversely affect forage production and would reduce phosphorus run-off thereby limiting algae growth.

Twenty-four test plots were established in a phosphorus deficient fescue pasture. Fertilizers were mixed and applied to the corresponding plots. The Control plots were not fertilized. Forage samples were taken every 45 days, dried, and weighed. Next, fescue sod boxes with metal spouts were constructed, and treated litter was applied. The sod fertilized with plain litter served as a control. Eight run-off water samples per treatment were collected and analyzed for soluble phosphates. Five samples of run-off water from each treatment were inoculated with Closterium algae culture. Live and dead algae cell counts were performed on Day 1 and 7 post inoculation.

The two salicylic acid treatments did not adversely affect fescue production as both salicylic acid litter treatments had significantly higher yields than the control plots. Neither salicylic acid treatment significantly lowered phosphate levels in the run-off water; however, they did adversely affect algae growth. The data indicated that the salicylic acid may have had a direct effect on the algae cells rather than chemically tying up the phosphates in the litter. Overall, the data indicated that the 10% alum treated litter  was the most effective litter treatment as it did not adversely affect forage production, significantly reduced run-off phosphate levels and adversely affected algae growth.

Balaji Sridhar
2004 U.S. Stockholm Junior Water Prize Finalist

Project Title: Optimization of a Novel Process of Removing Arsenic From Drinking Water Treatment Sludge


The source water in many public drinking water systems contains Arsenic (As) at levels above the U.S. EPA regulatory limit of 10 parts per billion (ppb). The most common method to reduce As concentration is co-precipitation in ferric hydroxide sludge. The high As levels present in the sludge make it a toxic waste requiring special disposal methods in toxic waste landfills. Any process that will decrease the volume of sludge will save money and benefit the environment. Furthermore, the upcoming 2006 regulations on As make innovation in this area vital and urgent.

The experimental approach has been:

Removal of As from the sludge by anion exchange (using phosphate), or by direct nitric acid elution, which is preferred.

Commonly available denitrifying bacteria have been used to remove nitric acid from the eluate by converting the nitric acid into harmless nitrogen gas.

The use of sulfate reducing bacteria (SRB) to precipitate As: the product from the denitrification process or the selective anion elution (phosphate eluate) is fed to an SRB reactor where sulfide anion is generated and reacts with the As and other metals to produce an insoluble As or metal sulfide. This precipitate is removed by filtration or centrifugation, thus greatly reducing the volume and mass of material that requires toxic waste landfill disposal. Calculations show that all the As from one (1) metric ton of sludge could be reduced to 200 grams of arsenic sulfide with this process; the remaining sludge is less toxic and can more easily be treated. The likelihood that the As will reenter the water supply is low, even in the unfortunate event of a leak from a landfill.

Abigail Hines
2004 U.S. Stockholm Junior Water Prize Finalist

Project Title: A Comparison of Herbs and Bti as Larvicides on Culex pipiens and Their Effect on Daphnia magna


If the best way to prevent a problem is to stop it before it starts, then the best way to control mosquitoes would be to kill them in the larval stage. That’s exactly what a larvicide does.

But, most of the larvicides that are used today are not recommended for use in wetlands because they are toxic to wildlife. There is one natural larvicide used called Bti or Bacillus thuringiensis israelensis. Bti is a soil bacterium that the larvae eat. It is environmentally safe for wetlands use and disintegrates in 48 hours.

Yet Bti is not without problems. First, it’s not as effective as some of the chemicals. The Ottawa Canada Health Dept. stated, "Bti is ineffective in mosquito breeding grounds, such as storm sewers or sewage lagoons." Also it does not work well in polluted waters. Since Bti is a food source, the larvae must eat it. If there are too many other food sources as in polluted water, the mosquito larvae may not eat it. Overdosing or high frequencies of applications of Bti has also caused some problems and has had an impact on nontarget organisms. In addition, a long term study done by Hershey over three years found that heavy Bti use did cause effects on the food web in the wetlands.

The purpose of my study was to find another natural oil or plant that would be as effective as or better than Bti, but still be safe for the environment. I wanted it to be safe for use in the wetlands, or if it was used in other areas and somehow leaked into the wetlands, it wouldn’t be harmful to the wildlife. In addition, perhaps these natural alternatives may be important in newly developing countries where many can’t afford costly chemicals.

Four herbal oils: neem, peppermint, marigold, and catnip were tested as larvicides. My hypothesis was that the herbs and Bti would act as larvicides, the most effective being peppermint, without being harmful to Daphnia magna. Daphnia are a major food source and key link in the aquatic food chain. They are also good bioindicators of an environment’s health.

I put thirty Culex pipiens larvae into serial dilutions of the oils with an emulsifier, EZmulse and they were tested at time intervals from 15min to 96hrs. Catnip and Peppermint oil concentrations were 3.125-50ppm. Neem and Marigold concentrations were 1ppm-8ppm. The LC50 was calculated at 24 & 48hrs. Marigold was most toxic with LC50 at 24hrs of 3ppm and LC50 at 48hrs of 2ppm. The order of toxicity of the oils for LC50 at 24-48hrs was Marigold>Catnip>Peppermint. Neem oil’s LC50 was above 8ppm and was not calculated. My hypothesis that peppermint would be most effective was wrong. In comparison, Bti (.17gm) killed all the larvae in 24hrs.

Then I did bioassays with thirty Daphnia in the same oil concentrations and Bti for 48hrs. The higher the concentration of the oil, the survivorship of the Daphnia decreased. LC50’s for each oil were lower at 24 & 48 hours than the mosquitoes. Bti had no impact on the survivorship of the Daphnia.

The emulsifier alone had no effect on the larvae, but in 50ppm all of the Daphnia died after 2hrs. Other studies have reported this observation that organisms died because of the inert substances in the larvicides. Further research should be done with this emulsifier using aquatic species.

Even though my project did not prove these herbal oils as effective as Bti, the need still exists for the development of more environmentally safe larvicides .It is important to protect our wetlands because they provide for everyone more than just a place of recreation. The wetlands work to recharge our ground water, protect our homes from floods and are home to one third of our threatened and endangered species.

Elizabeth Welsh
2004 Stockholm Junior Water Prize Finalist

Project Title: The Use of Barley Straw to Control Algal and Macrophyte Growth on Wild Rice Lake (Phase IV)


This four-year-study, which has extensively investigated the effect of barley straw on algae, was taken into the field for the first time in Wild Rice Lake—a shallow, 2100-acre lake north of Duluth, Minnesota. Common pondweed covers much of this lake by mid-summer, making fishing and boating difficult. Shallow lakes tend to be more fertile, and often weeds and algae pose a threat (Armstrong, 2003). Macrophytes have not overtaken Wild Rice Lake until recently, and algal levels remain low. With road construction and failing septic tanks, Wild Rice Lake is susceptible to possible eutrophication (Duluth News Tribune, 2003). Macrophytes and filamentous (blue-green) algae are difficult to manage (Newman, 1997). Barley straw applications in the United States are in the early stages of testing. This study, once again, looks at barley straws affect on algae with the addition of Lemna minor a common biological indicator species and common pondweed, the macrophyte causing problems in Wild Rice Lake (Welch, 1990). There are many ideas on how barley straw liquor controls and inhibits algal growth. It is thought that as barley straw rots, agents such as hydrogen peroxide, phenols and oxidized phenolics are produced (Gibson, 1990; Everall and Lees, 1996; McComas, 2001). These chemicals seem to limit the blue-green’s ability to up-take phosphorus (Ridge, 1996). One of the more current theories is that a diversion of phosphate occurs via the microbial loop (McComas, 2003). Past studies have shown that barley straw can be used to treat algal problems in a laboratory setting, but can barley straw be applied with the same results in a lake setting (Welsh, 2000; Welsh 2001; Welsh 2002)? The purpose of this experiment was to determine whether barley straw treatments could control macrophyte and possible future algal problems in Wild Rice Lake. The hypothesis is that barley straw application will control algal and macrophyte growth. To make the leap from a laboratory study to a field setting required more equipment and professional guidance. To begin the experiment, twenty 20-gallon limnocorrals were placed along the shoreline of Wild Rice Lake filled with 24 liters of undisturbed lake water. Plastic mesh bags of 240 grams of barley straw were added into two of the four trial buckets for each trial set—five trial sets in all. Fertilizer (0.1%) was then added into two of each set of four trial buckets, one with barley and one without. Thirty Lemna minor and four 14-centimeter lengths of common pondweed were added to two sets of the five, eight buckets in all. Chlorophyll a (Welsh et al), oxygen, pH and Lemna minor frond number were measured once a week for ten-weeks. Before and after the ten-weeks phosphate and nitrate levels were measured. The original hypothesis that barley straw would control algal growth was supported. Results show that barley treatment did significantly reduce algal growth when compared to the lake and control buckets (ANOVA p<0.001). Barley straw treatments also significantly decreased oxygen and pH in all trial containers (ANOVA p<0.001). The second half of the hypothesis was not supported; in that barley straw treatments significantly increased the frond number of Lemna minor in the limnocorrals treated with barley straw and fertilizer (ANOVA p<0.009). Barley straw treatments had no significant affect on the temperature of the buckets, and there was no significant difference in algal growth between the trial treatments with and without macrophytes. Phosphorus levels in the form of phosphate were significantly increased in the barley/fertilizer buckets when compared to the just fertilizer buckets, the opposite was true when nitrates were measured. This supports the idea that barley straw treatment diminishes algae’s ability to uptake phosphate. These higher phosphate levels could also account for the significant increase of L. minor in only the barley/fertilizer buckets. All common pondweeds added to macrophyte trials died by the third trial week, indicating that a better methodology is needed to measure their growth. Barley straw applications in the nutrient limited buckets did not significantly affect algal growth. This suggests that in nutrient limited situations (Wild Rice Lake), the application of barley straw is not indicated. Therefore, apply barley straw only in nutrient rich situations, and reapply after four weeks. This study also suggests that barley straw is not a feasible floating-leaf macrophyte control measure. In the future, barley straw application after a eutrophic situation has already occurred in a lake will be investigated.