LICHENS AS ENVIRONMENTAL MONITORS: MAPPING OF AIRBORNE TRANSPORT OF CONTAMINANTS FROM LAND DISPOSAL OF POULTRY WASTES WITHIN THE ILLINOIS RIVER WATERSHED

Poultry farming is intensively practiced in the Illinois River watershed located in northwestern Arkansas and northeast Oklahoma. Currently, over 100 million broiler chickens are produced annually within this watershed, and the production of these birds produces more than 300,000 tons of wastes annually. The wastes produced contain elevated levels of heavy metals and other harmful pollutants. Typically, poultry wastes are land disposed by surface spreading on pastures located near their source. Some of the waste particulates are small enough to become airborne. As a consequence, surface spreading of these wastes is a potential hazard to human health. Prior studies have shown that poultry wastes contain high levels of Zn, Cu and As, and that when poultry waste is disposed by surface spreading, arsenic-containing dust is generated. This arsenic-containing dust has been found in homes in Prairie Grove, AR and in air quality monitors at Fayetteville, AR. The purpose of this research is to determine if heavy metals characteristic of poultry wastes (Zn, Cu and As) vary in concentration within lichens growing on tombstones in the Illinois River watershed as a function of the amount of poultry litter spread upwind go these tombstones. Lichens are symbiotic organisms comprised of fungi, algae, and/or cyanobacteria. They can be used as effective monitors of airborne pollutants because they derive all their nutrition from the air. Hence, if an airborne pollutant is present in the vicinity of lichen it may be incorporated into its biomass. Preliminary results indicate that the concentrations of Zn, Cu and As found in lichen tissues correlate with the intensity of poultry waste disposal upwind of lichen sampling locations.