Geological structure and localization of mineralization at the Moryanikho-Merkurikhinskoye ore field

The paper discusses the lithological and facial features of the terrigenous-carbonate (biohermic) ore-bearing geological formation of the Moryanikho-Merkurikhinskoye ore field (Yenisei Ridge), which hosts stratiform lead-zinc deposits in carbonate strata. Ore-hosting lithofacies and their paleostructural position are characterized. Based on the previous studies, as well as the author’s own materials obtained as a result of field work, the main favorable lithological, facial and structural factors for hosting Moryanikhinsky-type stratiform lead-zinc mineralization are defined: the presence of paleodepressions within the shelf zone; development of carbonate rocks – dolomites, stromatolite dolomites and limestones, which are biohermic structures on the slopes of paleo-uplifts; the presence of an admixture of tuffaceous material in terrigenous rock varieties. The influence of tectonic faults on the formation of ore deposits and the morphology of ore bodies is indicated. The main types of ores of the Moryanikho- Merkurikhinsky ore field, as well as their mineral composition are described. The paper discusses the main ore types, as well as their mineral composition typical of the Moryanikho-Merkurikhinskoye ore field. The largest and well-studied lead and zinc stratiform Moryanikhinskoye deposit and Merkurikhinskoye ore occurrence located within the ore field are briefly characterized. The Moryanikhinskoye deposit is a typical example for searching for stratiform deposits of lead and zinc in the carbonate strata of the Angara-Bolshepitskaya mineragenic zone, which is of practical interest in developing predictive prospecting models of deposits and improving the efficiency of prospecting.

A Study of Soil Pollution by Road Runoff

Road runoff, a representative non-point source pollution, is known to seriously deteriorate the river water quality. In order to prevent river contamination due to road runoff, road runoff is infiltrated into the soil along the river. However, road runoff containing high concentrations of heavy metals and total petroleum hydrocarbons (TPH) can cause soil pollution. In this study, soil samples were collected at the point where road runoff flows, and the concentrations of heavy metals, such as cadmium, lead, and zinc, and TPH in them were compared with that in uncontaminated soil. Consequently, the concentration of heavy metals in the soil into which the road runoff flows was up to 21 times higher than that of the nearby uncontaminated soil. In conclusion, the discharge of road runoff into the soil seriously pollutes the soil. Therefore, direct discharge of road runoff to soil should be prevented to prevent soil pollution.

Environmental Impacts and Immobilization Mechanisms of Cadmium, Lead and Zinc in Geotechnical Composites Made from Contaminated Soil and Paper-Ash

Paper-ash is used for remediation of heavily contaminated soils with metals, but remediation efficiency after longer periods has not been reported. To gain insights into the mechanisms of immobilization of cadmium (Cd), lead (Pb), and znic (Zn), a study was performed in the laboratory experiment in uncontaminated, artificially contaminated, and remediated soils, and these soils treated with sulfate, to mimic conditions in contaminated soil from zinc smelter site. Remediation was performed by mixing contaminated soil with paper-ash to immobilize Cd, Pb, and Zn in the geotechnical composite. Partitioning of Cd, Pb, and Zn was studied over one year in seven-time intervals applying the sequential extraction procedure and complementary X-ray diffraction analyses. This methodological approach enabled us to follow the redistribution of Cd, Pb, and Zn over time, thus, to studying immobilization mechanisms and assessing the remediation efficiency and stability of newly formed mineral phases. Cd, Pb, and Zn were effectively immobilized by precipitation of insoluble hydroxides after the addition of paper-ash and by the carbonization process in insoluble carbonate minerals. After remediation, Cd, Pb, and Zn concentrations in the water-soluble fraction were well below the limiting values for inertness: Cd by 100 times, Pb by 125 times, and Zn by 10 times. Sulfate treatment did not influence the remediation efficiency. Experimental data confirmed the high remediation efficiency and stability of insoluble Cd, Pb, and Zn mineral phases in geotechnical composites.

Cadmio, Plomo y Zinc en el ostión Crassostrea virginica de la Laguna El Carmen, Tabasco, México / Cadmium, Lead and Zinc in the oyster Crassostrea virginica from Laguna El Carmen, Tabasco, Mexico

En el presente trabajo se empleó al ostión Crassostrea virginica, el cual es de gran importancia tanto para el comercio como para el consumo de las comunidades asentadas a lo largo del Golfo de México. El deterioro de las pesquerías del ostión, debidas principalmente a la contaminación ambiental, antropogénica y a la presencia de diversos metales pesados, ocasiona daños a la economía y a la salud de pobladores ribereños dedicados a la producción y captura de este recurso pesquero. Con la finalidad de establecer las concentraciones de cadmio, zinc y plomo encontradas en estos organismos y confirmar su importancia como bioindicadores de contaminación por estos metales, se planteó la realización de este trabajo. 50 ostiones fueron colectados por buceo autónomo mensualmente durante un año y analizados para conocer las concentraciones de metales pesados por cuadruplicado por medio de Espectrofotometría de Absorción Atómica. La mayor concentración de plomo fue encontrada en los ostiones del banco Yagua 1, con 9.90 µg g-1, seguida por Ostión largo (9.64 µg g-1) mientras que la mínima se reportó en Palma 1 con 8.96 µg g-1. Con respecto al contenido de Cadmio, las concentraciones se comportaron de manera similar que para el contenido de plomo: Yagua 1 Ostión Largo Palma 1. El contenido de Plomo en los tres bancos seleccionados, fue superior a los límites permisibles (NOM-001-ECOL-1996 y NOM-027-SSA1-1993), mientras que para Cadmio y Zinc en tejido de ostión no existen límites permisibles registrados para conocer el estado de salud de nuestra laguna.

Bio-availability and Bio-accessibility of Lead and Zinc in Contaminated Soil from Cwymystwyth Lead Mine Site

Cwmystwyth Lead Mine was an abundant mine site with pugh’s and kingside water drainages shows contaminated water in the research area with no much scientific evidence to ascertain the level of the pollution. Hence this research was designed to study level of lead and zinc in contaminated soil in which the bio-availability and bio-accessibility were measured. Sixteen (16) soil samples were taken at random using soil auger and a hand trowel. The samples were dried using an oven set at a constant temperature of 400oC for 72 hours. Wire mesh (250 microns) was used to sift the samples. The Unified (BARGE) method was used. The mimics mixtures of saliva, gastric, duodenal, and bile fluids. Three-stage mimic processes were performed, in the mouth, the stomach and intestinal cavities. All mimic digestive fluids were placed in the rotator water bath for 1hr at 37oC. The bioaccessibility of the soil Samples were analyzed by inductively coupled plasma-optical emission spectrophotometer (ICP-OES) method. The results were obtained using XRF and ICP methods. The percentage concentration of lead in the topsoil was 0.64% and in the bottom soil was 1.47%, with a total mean concentration of 1.06% in combined top and bottom soil. Zinc concentrations in the top and bottom soils were 0.22 and 0.45%, respectively, with a computed total mean of 0.34%. The findings revealed a highly significant difference between lead and zinc in both the top and bottom soil samples (LSD = P0.05). The average concentrations of lead and zinc extracted in both the stomach and intestinal stages were 15.98% and 1.23%, respectively

Detoxification of Arsenic-Containing Copper Smelting Dust by Electrochemical Advanced Oxidation Technology

A large amount of arsenic-containing solid waste is produced in the metallurgical process of heavy nonferrous metals (copper, lead, and zinc). The landfill disposal of these arsenic-containing solid waste will cause serious environmental problems and endanger people’s health. An electrochemical advanced oxidation experiment was carried out with the cathode modified by adding carbon black and polytetrafluoroethylene (PTFE) emulsion. The removal rate of arsenic using advanced electrochemical oxidation with the modified cathode in 75 g/L NaOH at 25 °C for 90 min reached 98.4%, which was significantly higher than 80.69% of the alkaline leaching arsenic removal process. The use of electrochemical advanced oxidation technology can efficiently deal with the problem of arsenic-containing toxic solid waste, considered as a cleaner and efficient method.