Keywords: mercurial sludge, sequential extraction, mercury mobility, mercury availability, environmental impact assessment, sustainable development, chlor–alkali plants, fractionation, sustainability, contaminated solid waste, environmental pollution, Cuba, toxicity, leaching, environmental risk, environmental weathering, waste treatment
Mercury mobility and availability in highly contaminated solid wastes from a chlor–alkali plant
This article suggests an approach of sustainable development in Cuba based on the environmental impact assessment of mercurial sludge generated by a chlor–alkali Cuban plant. It consists of a study of mercury mobility and availability in the sludge samples using sequential extraction procedure. High values of total mercury content (2320 ± 40 mg/kg) in the sludge sample as well as in the toxicity characteristic leaching procedure (TCLP) extract (0.46 ± 0.02 mg/l) were obtained. The highest Hg concentration (52.2 ± 1.5%) was found in the mobile fraction (F1 + F2) indicating a high risk of Hg mobilisation by the presence of water–soluble and exchangeable mercury compounds such as HgCl2, HgSO4 and HgO. The water–soluble fraction (F1) accounts for the 13.7 ± 0.8% of total Hg representing a significant environmental risk due to its easy availability in environmental weathering conditions. The mercury fractionation analyses clearly demonstrate that the chlor–alkali Cuban plant does not represent a sustainable technology from environmental point of view. Furthermore, this study highlights the presence of a wide range of mercury compounds which represents a significant parameter for developing a sustainable technology to treat the mercurial sludge generated by the chlor–alkali Cuban plant.