Fate and transport of organic compounds in municipal solid waste compost

Four chemicals, polychlorinated biphenyls (PCB), benzo(a)pyrene (B(a)P), a-chlordane, and bisethylhexyl phthalate (BEHP), were chosen for investigation because of their range of physical/chemical properties and because they have been reported in municipal solid waste compost in the literature. Field studies were performed by applying amended compost, which was spiked with the four chosen organic chemicals, into corn, fescue, and poplar fields in Amana, Iowa. The Pesticide Root Zone Model II (PRZM II), a U.S. EPA computer code (Dean, et al., 1989), was utilized to predict the potential fate and transport of four chemicals in the unsaturated zone. Model input consisted of meteorological records from nearby weather stations, soil data from the Amana site and laboratory results/literature values of chemical properties. Results indicate that, due to their relatively low solubility and high hydrophobicity, the chemicals are quite sorptive to the soil/compost mixture and barely migrate vertically in the soil. In five year simulations, the chemicals remained within the rooting zone of the plants and slowly biodegraded. Plant uptakes were relatively small and essentially no leachate reached the groundwater table. Volatilization of PCB and chlordane was significant only for the top soil layer. A field study is being used to verify the modeling results.