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PHYTOTRANSFORMATION OF PERCHLORATE USING PARROT-FEATHER
Citation:
Susarla, S., S T. Bacchus, N L. Wolfe, AND S C. McCutcheon. PHYTOTRANSFORMATION OF PERCHLORATE USING PARROT-FEATHER. SOIL & GROUNDWATER CLEANUP February/March:20-23, (1999).
Description:
Perchlorate is an oxvanion that has been extensively is a strong oxidizing
agent in solid rocket fuel. Contamination of groundwater has occurred as the result of Perchlorate use. Standard disposal practices during the 1950s through the 1970s did not reflect the current knowledge of environmental impacts of these fuels on groundwater and soils. Wastewater generated from the manufacturing, maintenance and testing of solid rocket propellants can contain ammonium Perchlorate concentrations in the range of grams per liter. It is estimated that over the next eight to ten years approximately 75 million kg of Perchlorate may be ready for disposal. Perchlorate currently is not regulated under the Safe Drinking Water Act, although the California Department of Health Services has established an action level for Perchlorate in drinking water of 18 micrograms/L. The primary human health concern related to Perchlorate is that it interferes with the ability of the thyroid gland to utilize iodine to produce thyroid hormones. These hormones are required for normal metabolism, as well as growth and development. The effect of Perchlorate on thyroid hormone function is the competitive inhibition of iodide anion uptake into the thyroid gland by Perchlorate anion. This results in reduced thyroid hormone production, and interferes with the normal function of the thyroid gland, suggesting that Perchlorate is an endocrine disrupter. A cost effective Perchlorate treatment process was developed using a consortium of facultative anaerobic microorganisms and Wolinella succinogenes HAP-1. However, at low concentrations the microorganisms preferred other electron acceptors (e.g., nitrate) to Perchlorate, and the process failed. Consequently, the developer of efficient and cost effective strategies for the remectiation of Perchlorate in groundwater is of immense interest. Recently parrot-feather has been used successfully to remediate TNT contaminated soils, and other contaminants (e.g., TCE and PCE). The use of plants to cleanse soil and water contaminated with pollutants has great potential because complete transformation of compounds into nonhazardous end products has been reported. The objectives of th described research were to evaluate the ability of the aquatic plant, parrot-feather, to remove perchlorate from an aqueous solution; to determine the rate of perchlorate removal from solution; and to identify transformation products in roots, stems and leaves.