Lemna sp. as a Chromium Heavy Metal Phytoremediator on Tannery Wastewater and its Potential Use as Fish Feed

Abstract

Aims: This research aims to determine the ability of Lemna sp. as a phytoremediation agent in absorbing chromium (Cr) in tannery wastewater.
 Study Design: A total of 20 fiber tubs with size 80 x 80 x 40 cm3 and volume of 256 L were prepared and filled with 30 L each of the tannery wastewater and 1.75% bio-slurry added with a volume of wastewater as a source of nutrition for Lemna sp.. The number of Lemna sp. which is used for culture was 180 g for each fiber tube.
 Place and Duration of Study: Culturing Lemna sp. in tannery wastewater were carried out in Ciparanje Land Fisheries Area of ​​the Faculty of Fisheries and Marine Sciences Universitas Padjadjaran and for chromium analysis were carried out in Center for Natural Resources and Environment Research of Universitas Padjadjaran, between February and March 2019.
 Methodology: This research was carried out by culturing Lemna sp. in tannery wastewater for five days with 20 replications and comparing Cr concentrations in tannery wastewater and Lemna sp. at the end and beginning of the research. Chromium analysis results on the tannery wastewater and Lemna sp. the beginning and end of the research on each sample was tested by paired t-test.
 Results: by culturing Lemna sp. in the tannery wastewater as phytoremediation agent for five days the results obtained Cr concentration at the beginning of research each for tannery wastewater and Lemna sp. ranged from 0.180 to 0.194 mg/L with an average of 0.187±0.0034 mg/L and 0 mg/kg. While at the end of the research the concentration of Cr in tannery wastewater and Lemna sp. respectively ranged from 0.057-0.075 mg/L with an average of 0.068±0.0044 mg/L and 2.292-2.333 mg/kg with an average of 2.314±0.0101 mg/kg. There was a decrease in Cr concentration by an average of 64.01±1.96% in tannery wastewater and an increase in Lemna sp.. Paired t-test results showed that Lemna sp. which was cultured in tannery wastewater had a significant influence on Cr concentrations in both tannery wastewater and Lemna sp so that there were significant differences in Cr concentrations at the beginning (day 0) and at the end of the research (day 5).
 Conclusion: Average ability of Lemna sp. in absorbing and accumulating chromium in the tannery wastewater in the tissue was 2.314±0.0101 mg/kg and the average reduction in Cr concentration in liquid waste was 64.01±1.96%. Utilization of Lemna sp. containing chromium is possible to be used as a food supplement for fish to increase growth due to reduced Cr toxicity by Lemna sp.