Evaluation of Cajanus cajan (pigeon pea) for phytoremediation of landfill leachate containing chromium and lead |
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Authors: | José A. Jerez Ch. |
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Affiliation: | Escuela de Química y Centro de Investigaciones en Productos Naturales (CIPRONA), Universidad de Costa Rica, Ciudad Universitaria Rodrigo Facio, San Pedro de Montes de Oca, San José, Costa Rica |
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Abstract: | Landfill leachates containing heavy metals are important contaminants and a matter of great concern due to the effect that they might have on ecosystems. We evaluated the use of Cajanus cajan to remove chromium and lead from landfill leachates. Eight-week-old plants were submitted to varied tests to select the experimental conditions. Water assays with a solution (pH 6) containing leachate (25% v/v) were selected; the metals were added as potassium dichromate and lead (II) nitrate salts. Soil matrices that contained leachate (30% v/v) up to field capacity were used. For both water and soil assays, the metal concentrations were 10 mg kg?1. C. cajan proved able to remove 49% of chromium and 36% of lead, both from dilute leachate. The plants also removed 34.7% of chromium from irrigated soil, but were unable to decrease the lead content. Removal of nitrogen from landfill leachate was also tested, resulting in elimination of 85% of ammonia and 70% of combined nitrite/nitrate species. The results indicate that C. cajan might be an effective candidate for the rhizofiltration of leachates containing chromium and lead, and nitrogen in large concentrations. |
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Keywords: | phytoremediation Cajanus cajan landfill leachates chromium lead heavy metals waste disposal |
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