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PM12 Metals in the Environment
(PM210) Distribution and fate of background and bioavailable metals in Oregon agricultural soils and plants.
Perez, Angela1, 2, Anderson, Kim1, 2, 1 Department of Environmental and Molecular Toxicology, Corvallis, OR, USA2 Food Safety & Environmental Stewardship Laboratory, Corvallis, OR, USA
ABSTRACT- Many fertilizers on the market today contain metals including arsenic (As), cadmium (Cd), lead (Pb), mercury (Hg) and nickel (Ni). Arsenic and Ni are both toxic and carcinogenic, while Hg, Pb, and Cd cause adverse effects in a multitude of physiological processes in humans including neurological, vascular, nephro- and hepato- toxicity, and skeletal deformities. Toxicity of metals on plant and aquatic life have been studied, however, little information exists correlating chronic fertilizer application and adverse effects to terrestrial and aquatic ecosystems. Few studies have analyzed for the bioavailable fraction of metals and little is known about potential accumulation of metals in plant material used for human consumption. This research aims to determine the bioavailable fraction of metals in soils amended with fertilizer; to evaluate site to site variation; investigate effects of multiple doses, and estimate Kd. An evaluation of ecological and human health risk associated with bioavailable metal exposure will be conducted. Four research sites in Oregon have been selected, representing diverse soil systems and two distinct crops, winter wheat and potatoes. Treatment includes a control, 1x, 2x, and 3x the recommended application rates and each treat is replicated 4 times. Sampling events occur twice annually, once shortly after fertilizer application (leaving ample time for weathering and solubilization), and again during harvest. Collection consists of 384 surface samples (0-20cm) 32 DGT samples and 16 deep soil samples (1 m) per year. Chemical characterization of soils for each site is completed annually, including: pH, NO3, NH4, K, P, SO4, B, organic matter, and cation exchange capacity. Soil analysis methodology includes diffusive gradient thin films (DGT) to estimate bioavailability and Kd, analysis with inductively coupled plasma atomic emission spectrometry (ICPAES), ICP mass spectrometry (ICPMS), and samples high in arsenic are measured to determine the concentration of toxic As (III) using anodic stripping voltametry.
Key words: trace metal, bioavailability
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