Phytoremediation of arsenic contaminated ground water using water lettuce (pistia stratiotes) (T-1580) (MFN 8630)

Abstract

Research was conducted to assess the potential of Water Lettuce (Pistia stratiotes) to remediate the arsenic contaminated ground water. Ground water was sampled from three different villages near Lahore i.e. Khudpur, Mangamandi and Gopirai. All the villages showed higher arsenic concentration than the permissible limits i.e. 10μg/L, whereas, the physiochemical parameters pH, total dissolved solids (TDS) and electrical conductivity (EC) were found under the WHO and Pak-EPA permissible limits. Khudpur showing the most concentration of 500 μg/L was considered for further study. Five different concentrations were created from 500 μg/L i.e. 300 μg/L, 200 μg/L, 100 μg/L, 50μg/L and 25μg/L. Water Lettuce plants was used as hyper-accumulators to remediate the arsenic contaminated ground water. After the initiation of the process the water samples were collected after every 3rd day, the process lasted for 21 days. The collected water samples were analyzed for total arsenic concentration. Water lettuce (Pistia stratiotes) reduced the arsenic concentrations in container no.1 from 300 μg/L o 100 μg/L, in container no.2 from 200 μg/L to 50μg/L, in container no.3 from 100μg/L to 25 μg/L, in container no.4 from 50μg/L to 10 μg/L and in container no.5 from 25 μg/L to 0 μg/L. Water lettuce (Pistia stratiotes) showed 100% efficiency in the container no.5, 80% in container no.4, 75% in container no.3 and 2, 66.67% in container no. 1. At the end the bioaccumulation coefficient was calculated. Bioaccumulation coefficient was found decreasing in the following order; container no.5> container no.4> container no.3> container no.2> container no.1. Water Lettuce was found efficient for the removal of arsenic from ground water.