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Low-Cost Adsorbents of Natural Origin for Reducing Pesticides and Heavy Metals Impact on Environmental Quality

Investigators
Antonious, George
Institutions
University of Kentucky
Start date
2008
End date
2012
Objective
Soil erosion, nutrient runoff, loss of soil organic matter, and the impairment of environmental quality from sedimentation and pollution of natural waters by agrochemicals, heavy metals, and other environmental contaminants have stimulated interest in proper management of natural resources. There is an urgent need to develop long-term, low-energy, biological, self-sustainable systems of farming. Methods of application of these systems must be simple, inexpensive, energy conserving, safe and effective for pesticide mitigation, nutrient recycling and erosion control. Although many factors are responsible for decomposition of pesticides in soils, two are considered the most important: a) adsorption increases the availability of the pesticide for degradation processes, and b) microbiological activity increases pesticides metabolism. Municipal sewage sludge and chicken manure are among the biologically rich organic amendments of natural origin. However, their high levels of heavy metal ions pose an environmental threat.

The objectives of this investigation are: 1) to remove pesticide residues and heavy metal ions from agricultural soils incorporated with sewage sludge or chicken manure using adsorbents of natural origin; 2) to remove pesticide residues and heavy metal ions from runoff and infiltration water from soils incorporated with sewage sludge or chicken manure using biobed systems. Biobeds provide a potential solution to pesticide contamination of surface waters arising from farmyards. Nine units of biobed systems will be installed down the land slope of specially designed runoff plots at KSU research farm to retain and degrade pesticides before they runoff from the arable zone into streams and rivers; 3) to determine the impact of soil amendments and biobeds on soil microorganisms and microbial processes as biological indicators of soil health; 4) to determine bioavailability of heavy metals in soil amended with sewage sludge or chicken manure. Like pesticides, immobilization of the heavy metals (Cd, Cr, Ni, Pb, Zn, Cu, and Mo) content of soil amendments will reduce their mobility in soil, surface water, and into edible plants at harvest to satisfy heavy metal permissible levels and federal regulations and standards; and 5) to develop a standardized constructed wetland system for treatment of wastewater discharge containing pesticide residues and fertilizers. This wetland will be a model state-of-the-art system utilizing phytoremediation technology that will be developed with collaboration with chemical companies to facilitate application, transfer, and adoption by the private sector.

The project will be of value at the regional level and at state and national levels and will provide economic solutions to environmental pollution by pesticides and heavy metals released from arable lands.

More information
Non-Technical Summary: Contaminated runoff from farmland contributes a significant proportion of the pesticide load released to surface waters. There is an urgent need to develop long-term, low-energy, biological, self-sustainable systems of farming. Methods of application of these systems must be simple, inexpensive, energy conserving, safe and effective for pesticide mitigation, nutrient recycling and erosion control. New soil management practices are needed to develop and expand our knowledge and technical means of agricultural production systems related to the fate and transport of agricultural chemicals into runoff and infiltration water. Pesticide use, while being of great benefit in controlling weeds, insects, and pathogens in agricultural systems, can also pose a threat to environmental quality. The increasing concern about agricultural chemicals and their impact on surface and groundwater quality has made this a national concern. Municipal sewage sludge (biosolids) and chicken manure are among the most commonly used soil amendments in the U.S. As more sewage treatment districts turn to composting as a viable means of sludge stabilization and because of the rapid growth in the poultry industry, significant chicken manure and municipal sewage sludge generation will become available in increasing quantities. Very few studies have been carried out on the mobility of pesticides and heavy metals from soil incorporated with sewage sludge or chicken manure amended soils into runoff water. Pollution of soil by heavy metals through the addition of metal containing organic waste is a real threat to soil quality. Although microorganisms require metals for growth and activity, heavy metals are toxic to the microorganisms when they are present in excessive concentrations. The overall goal of this proposed study is to develop a sustainable agricultural technique that strikes an acceptable balance between crop production benefits and ecological conservation by reducing pesticides and heavy metals impact on water quality. The proposed research has three objectives: 1) to remove pesticide residues and heavy metal ions from runoff, infiltration water, and agricultural soils incorporated with sewage sludge or chicken manure; 2) to monitor microbial activity in soil as affected by soil management practices; 3) to enhance student learning in environmental science by increasing students' hands-on training in field and laboratory experience and to assist students in writing quality research papers for publication/presentations in environmental quality. The project takes the advantage of state-of-the-art capabilities available at KSU/CRS including universal soil loss equation (USLE) standard plots for quantification of runoff, pan- and tension-lysimeters for collecting infiltration water from the vadose-zone. At KSU/ Water Quality Research new analytical procedures have been developed for determining pesticide residues and their degradation products in soil, runoff and infiltration water. All this knowledge and expertise will be used to insure the successful completion of the outlined proposed objectives.

Approach: The field trial area will be on 10% slope located at the KSU Research Farm. The farm is located in the Kentucky River Watershed in the Blue Grass Region. Eighteen field plots of 3.7 m wide and 22 m long each with metal borders along each side were established. At the bottom of each plot a tipping-bucket runoff metering apparatus, and a pan lysimeter have been installed for collecting runoff and infiltration water following natural rainfall events. Plots will be planted with cabbage (year 1); Peas (year 2) as two aboveground crops; potato (year 3); and turnip (year 4) as two underground crops. The experimental design will be 2x2x3 factorial including two pesticides: 1)an herbicide and 2)an insecticide formulation, and three fixed factors including three soil management practices (sewage sludge, chiken manure application, and a rototilled bare soil that will be used for comparison purposes). The field experiment will be conducted using the two pesticides Treflan HFP 4E and Thiodan 3EC during the 2009 cropping season. In year 2010 cropping season, the experiment will be conducted using Command 3ME and dimethoate 4EC. In 2011, the study will be conducted using Poast 1.5E and Baythroid 15G. In 2012, turnip will be planted and two pesticides, Sencor 75 DF and Lorsban 15G, will be applied under field conditions. Soil samples will be collected using a soil core sampler, dried, sieved to a size of 2 mm, and extracted using soxhlet extraction apparatus, solid-phase extraction (SPE) technique or liquid-liquid partition depending on the pesticide under consideration. Soil Samples will be also oven-dried and ground manually with a ceramic mortar and pestle to pass a 1 mm sieve. Mehlich-3 extractable Cd, Cr, Ni, Pb, Zn, Cu, and Mo will be determined in soil extracts using Inductively Coupled Plasma (ICP) spectrometry. Runoff will be collected and quantified at the lower end of each plot. Sediment loss will be determined. The activity of the three enzymes involved in the C, N, and P cycles (Invertase, urease, and phosphatase, respectively) will be determined and used as indicators of increased microbial populations, as predictors of soil fertility, and as indicators of toxic effects of sludge-borne or chicken manure-borne metals on soil organisms. Evaluation plans: Weekly meetings will be conducted between PI (Dr. Antonious), Co-PI, RA, and student/analyst working on the project. These meetings will assess current progress and update all persons on successes and failures of the past week so that changes can be made if necessary. Analysis will be carried out in timely manner. The ultimate accomplishments and progress will be judged also by interest expressed by the two minority farmers who are current users of sewage sludge. The criteria for evaluating the effectiveness of the overall proposal will be achieved also through the students' presentations and publications. We will have a field day to show the farmers the results of using sewage sludge on our KSU farm demonstration plots. We will present the results at the Kentucky Small Limited Resource Minority Farmers Conference.

Funding Source
Nat'l. Inst. of Food and Agriculture
Project source
View this project
Project number
KYX-10-08-43P
Accession number
216090
Categories
Chemical Contaminants
Pesticide Residues
Commodities
Produce
Grains, Beans, Legumes
Meat, Poultry, Game