Bioremediation Using Ulva Reticulata On Heavy Metals And Nutrients From Bayan Lepas Free Industrial Zone, Penang, Malaysia
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Date
2016-09
Authors
Khodami, Sharareh
Journal Title
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Publisher
Universiti Sains Malaysia
Abstract
Effluent waters from the Bayan Lepas Free Industrial Zone (FIZ) in Penang, Malaysia are discharged into several drainage canals and in Keluang River, where water is finally released into the open sea facing Jerejak Island. This study was performed to investigate the ability of Ulva reticulata to uptake heavy metals and nutrients from the effluent water from the Bayan Lepas FIZ. Five sampling stations were selected along the Keluang River, and five stations along the Bayan Lepas coastal area. Water and sediment samples were collected during low tide in October 2012 and February 2013 to represent wet and dry seasons, respectively. Nutrients, metals (Cd, Cr, Cu, Co, Fe, Pb, Ni, V, and Zn), and physicochemical parameters of the water evaluated. Results indicated that Keluang River was polluted with ammonium (0.040–6.233 mg/L), phosphate (0.049–1.110 mg/L), Cu(1.6–1210 μg/L), and Ni (1.5–377.5 μg/L). The enrichment factor (EF) of metals in the sediments varied between no enrichment and extremely excessive enrichment. Among the metals detected, Cd (105.66), Cu (99.055), Pb (26.178), and Ni (8.086) had the highest EF values in Keluang River. The ability of U. reticulata to absorb nutrients varied, as follows: nitrate, 0.392 –0.871 μmol gfw−1 h−1; ammonium, 1.14–2.38 μmol gfw−1 h−1; and phosphate, 0.171–0.663 μmol gfw−1 h−1. Nutrient uptake was controlled by circadian clock such that uptake was higher during day time (when light is available) and lower during night (darkness). The circadian clock for the uptake could be altered. Ammonium uptake increased with increasing light intensity
and initial ammonium concentration. The maximum velocity ( ) value indicated a rapid ability to take up ammonium at high ammonium concentration. Nutrient uptake in the Bayan Lepas effluent water revealed that the maximum ammonium and phosphate uptake rates occurred during the first hour of exposure in 300 μM ammonium and 50 μM phosphate of initial concentration, respectively ( and were 32 and 4 μmol gfw−1 h−1). Ulva reticulata removed 92.4% of ammonium and 90% of phosphate from water within 24 and 48 h, respectively. These results showed that U. reticulata is an effective biofilter for ammonium and phosphate removal from effluent water of Bayan Lepas. All metal uptakes occurred in two stages and peaked within 1 h. Metal uptake was higher in single-metal media than mixed-metal media. In the experiment using similar concentrations of mixed metals, metal uptake was in the order of Pb > Cd > Ni > Cu. Metal uptake changed to Cu > Ni > Cd > Pb in media containing metals mixed with nutrients similar to those in Bayan Lepas FIZ effluent. Metal uptakes increased with increasing initial metal concentration. Metal uptake by dried U. reticulata was higher than that of fresh U. reticulata under different conditions such as contact time, pH, salinity, amount of U. reticulata, temperature, and agitation speed. Initial concentrations of metals in U. reticulata were ranked as follows: Mg > Fe > Zn > Mn > Ni > Cu > Cr > Co > Cd = Pb > V. However, the sequence of metal concentration in the tissue changed after exposure to the experimental conditions for 24 h. The uptake capability of U. reticulata depended on metal concentration in water and experimental conditions. The content of metals, such as Cu, increased by 10-fold after the exposure. This study demonstrated that U. reticulata can absorb nutrients and metals from effluent water. This plant can be used as a bioremediation agent to improve the quality of water in industrial areas prior to discharge.
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Keywords
Effluent waters from the Bayan Lepas , Free Industrial Zone (FIZ) in Penang