Submitted to: Bioremediation Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/20/2007
Publication Date: 11/29/2007
Citation: Moore, M.T., Cooper, C.M., Kroger, R. 2007. Using rice (Oryza sativa) as a potential phytoremediation tool for nutrient runoff. 11(4):165-170. . Bioremediation Journal. Interpretive Summary: Excessive nutrients entering rivers, lakes, and streams, pose a risk to fish and other inhabitants of the aquatic ecosystem. A small-scale outdoor experiment was conducted to determine the ability of rice plants to clean up water containing excessive levels of nitrogen and phosphorus. Rice was capable of decreasing nutrient concentrations by 10-55% in water with nutrient concentrations of 5 mg/L. When concentrations reached 10 mg/L, the experimental scale systems failed to remove any nutrients. Aquatic vegetation (e.g. rice) is a useful tool for phytoremediation efforts to decrease nutrient concentrations in agricultural runoff water.
Technical Abstract: Hyper-eutrophication of US surface waters is one of the leading causes of impairment for water quality. With nutrient criteria development and total maximum daily load (TMDL) issues looming for regulators, agricultural research is focusing on practices aimed at decreasing nutrient contributions to receiving aquatic ecosystems. This study examined the use of rice (Oryza sativa) for luxury uptake of nitrogen and phosphorus components associated with agricultural storm runoff. Mesocosms (379 L) planted with rice were exposed to two concentrations (5 mg/L and 10 mg/L) of nitrate, ammonia, and orthophosphorus. Results from these mecocosms were compared to unvegetated controls to determine efficiency of rice in remediating nutrient runoff. Retention of nitrate and ammonia in all mesocosms was improved when compared to orthophosphate retention. Statistically significant differences were noted in ammonia, filtered orthophosphorus, and total orthophosphorus concentrations of vegetated mesocosms amended with 5 mg/L versus unvegetated controls amended with 5 mg/L. Although rice is a nutrient-dependent aquatic plant, this study suggests that more efficient mitigation is possible at lower inflow concentrations as opposed to higher inflow concentrations.