ENVR 14 |
| Yong Cai, Zhangrong Chen, Alejandro Jaramillo, George H. Snyder, Ming Chen, and John L. Cisar. |
| The impact of extensively used arsenic-containing herbicides on ground water beneath golf courses has become a topic of interest. Although currently used organoarsenicals are less toxic, their application into the environment may produce the more toxic inorganic arsenicals. Over the last few years, our research team has been conducting studies to understand the key factors and processes controlling arsenic transport and transformation in Florida golf course soils. This paper will summarize the results from our field and laboratory experiments. The results from the field experiments conducted at the Fort Lauderdale Research and Education Center, University of Florida, showed that the substrate composition significantly influenced arsenic mobility and arsenic species transformation in the percolate water. Arsenic species transformation occurred in soil, resulting in co-occurrence of four arsenic species, arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in percolate water. The clay coatings on the soil particles and the addition of peat in the soil changed the arsenic bioavailability, which in turn controlled the microorganism-mediated arsenic transformation. The adsorption kinetics of AsV and MMA to soil substrate were characterized using equilibrium batch experiments. Heterogeneous colloid-binding characteristics of arsenic were also evaluated using the equilibrium dialysis technique. A three-component equilibrium model was proposed to describe the partitioning of arsenic species in the water, colloidal and soil system and to estimate the arsenic distribution coefficients among these three phases. Column experiments were conducted to simulate arsenic transport through golf course soils in the presence and absence of soil-derived colloids. The transport and transformation of arsenic species is influenced by a combination of microbial and physicochemical properties and processes. Arsenic species transformation occurred under the column conditions and had a significant impact on arsenic transport for both arsenic species tested (AsV and MMA). |
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Occurrence, Chemistry, Toxicity and Remediation of Arsenic
8:00 AM-11:00 AM, Sunday, 26 March 2006 Georgia World Congress Center -- B218, Oral
Division of Environmental Chemistry |