Papers by Keyword: Toxic Elements

Abstract: The paper deals with development of cementitious binders that would be able to efficiently immobilize toxic elements contained in various types of wastes. The basic component of the proposed binders are clinkers with phosphorus incorporated into the structure of clinker silicates, mixtures of cement with ash containing hydroxylapatite and belite-rich clinkers activated with sulfate anions. The prepared binders were mixed with water doped with various toxic elements; after a defined period of cement stone hydration the test beams were subjected to long-term testing of leachability of individual toxic elements. The research methods involved besides leaching tests also optical and electron microscopy.

Abstract: Objective: A method based on high pressure digestion andinductively coupled plasma mass spectrometry (ICP-MS) detection was establishedfor determination of arsenic, mercury, lead, cadmium, chromium and thallium inbiological tissues. Method: The samplesof hair, nails, viscera, blood, urine were digested with HNO₃ and H₂O₂in high pressure digestion tank ; Indium was used as internal standard element,The certified GBW07601a (CRM Human Hair) was adopted as the quality control forthe whole processes. Results: Theexcellent sensitivity and reliability were demonstrated by the method ofrecovery 82% ~ 110%, RSD (n = 5) less than 5% and the linear range of 0.020ng/mL to 100 ng/mL (r > 0.99). The prototype measurements are within thescope of the standard value. Standard addition recovery of the six elements is therange of 92% ~ 105%. Conclusion: Arapid, easy and accurate quantitative ICP-MS method was established fordetermination of toxic elements in the human body, which enrich the existing meansof forensic technology. At the same time, this work provide the most practicaland reliable core data for poisons metabolism and pathological study.

Abstract: Levels of toxic elements in fish from fishing ground using geothermal water in Guanzhong Basin, China were investigated. Six elements including elements cadmium (Cd), arsenic (As), copper (Cu), fluorine (F), lead (Pb) and chromium (Cr) in fish were emphatically assessed because they were limited by safety requirements for non-environmental pollution aquatic products (GB/T18407.4-2001). Element F, Cr，Cu，As，Cd and Pb concentrations in fish muscle were in the range of 4.3-18.2 mg/kg wet weight (ww), 0.21-1.53 mg/kg ww, 2.34-2.92 mg/kg ww, nd-0.08 mg/kg ww, 0.01-0.13 mg/kg ww and 0.05-1.99 mg/kg ww, respectively. Element F concentration in each fish muscle was higher than its tolerance limit (2.0 mg/kg ww). Element Cd concentration in Tilapia muscle from Beida fishing ground exceeded its limit value (0.1 mg/kg ww). Tilapia muscle from Tezhong and Beida fishing grounds and Ctenopharyngodon idella muscle from Heyang and Changda fishing ground contained more than the safe limit of Pb (0.5 mg/kg).The bioconcentration factor (BCF) of 6 elements for fish muscle of ctenopharyngodon idella from Heyang and Changda fishing grounds were calculated. The results suggested that using geothermal heat for fish breeding may lower BCF of F and Cr but enhance bioaccumulation of Cu, As, Cd and Pb in fish muscle, which may increase health risk.

Abstract: The processing and recycling experiments of dust from Electric Arc Furnace (EAF) in industrial conditions aimed at highlighting the minimizing possibility of this waste by transforming it into a by-product that can represent either a secondary raw material for steel making in EAF or to recover iron, zinc and lead (the Waltz process). Electric-arc furnace dust (EAFD) is a by-product of steel production and recycling. This fine-grained material contains high amounts of zinc and iron as well as significant amounts of potentially toxic elements such as lead, cadmium and chromium. Therefore, the treatment and stabilization of this industrial residue is necessary. Leaching test is a method of evaluating the impact of waste that is stored (soil, water table).