Heavy metals in microalgae biomass added with different concentration of wet market wastewater

The aim of this study is to assess heavy metals content namely arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) in microalgae Scenedesmus sp. biomass cultivated with wet market wastewater. Microalgae Scenedesmus sp. is added to wet market wastewater which contains high nutrient level that has a potential to be made into fish supplement products. However, this process depends on the level of heavy metals in the wastewater. Different concentrations of wet market wastewater were tested in the dilution of 10% (10WM), 15% (15WM), 20% (20WM) and 25% (25WM) during the cultivation to measure the potential by-product quality. As, Cd, Pb and Hg heavy metals in dry biomass of Scenedesmus sp. were measured using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Mercury Analyser. Heavy metals content (ug/kg in ppb) in the Scenedesmus sp. were found in the range of 182.5-7.74 for As, 0.985-3.111 for Cd, 4.95-2.375 for Pb and 9.774-1.037 for Hg. Arsenic was the highest trace metal (182.5 ppb) found in 25WM and the lowest (0.311 ppb) was Cadmium from Bolt’s Basal Medium (BBM) sample. The level of heavy metals in all microalgae biomass samples did not exceed the maximum concentration set up by the European Commission Regulation. Therefore, the biomass from microalgae Scenedesmus sp. cultivated with wet market wastewater has acceptable concentration of As, Cd, Pb and Hg. Thus, it has a great potential to be processed into bioproducts such as fish feed and fish supplement.