Rusnam and Efrizal
This research was conducted on July – October 2013 about a mercury analysis which has been performed in Environmental Engineering Laboratory of Engineering Faculty, Andalas University. The level of mercury that is permitted by Government Regulation Republic Indonesia No. 82 of 2001 at the fourth grade for water are at 0.005 mg/l. In that analysis, mercury contents with 0.020169 mg/l at irrigated areas in Batang Hari River. This research aims to find out the ability of water lilies (Salvinia molesta), wood lettuce (Pistia stratiotes), and water hyacinth (Eichhornia crassipes) to decrease the content of water level. This research used experimental methods and the initial content of heavy metals mercury (Hg) by using 0.02 mg/L, 0.06 mg/L, and 0.1 mg/L. The results at decreasing concentrations of heavy metals mercury will be compared with the quality standard of heavy metal mercury at the fourth grade of water. The result showed that water lilies (Salvinia molesta), wood lettuce (Pistia stratiotes), and water hyacinth (Eichhornia crassipes) were able to fix the water quality for irrigation which contaminated heavy metal (Hg). Then, mercury concentration reached a quality standard for irrigation at early concentration 0.02 mg/L during the 15 days and at early concentration 0.1 mg/L during 35 days. From the analysis, it was found that Water hyacinth (Eichhornia crassipes) is the best plant to decrease the concentration of heavy metals mercury.