INTRODUCTION Chlorinated ethanes and ethenes are among the most frequently detected organic pollutants of water. Their physicochemical properties are such that they can contaminate aquifers for decades. In favourable conditions, they can undergo degradation. In anaerobic conditions, chlorinated solvents can undergo reductive dechlorination. DEGRADATION PATHWAYS Abiotic dechlorination is usual...

Jarosite, KFe(3)(SO(4))(2)(OH)(6), is a secondary iron sulphate often found in acid mine drainage (AMD) environments, particularly in mining wastes from polymetallic sulphide ore deposits. Despite the negative environmental connotation usually ascribed to secondary sulphate minerals due to the release of hazardous elements to aquifers and soils, jarosite acts as an efficient remover and immobil...

The kinetics and mechanisms of dissolution of the major base metal sulphide minerals, pyrite, chalcopyrite, galena and sphalerite in acidic (chloride) media have been investigated. Minerals were ground in air, then dissolved in air-equilibrated solutions at pH 2.5, while monitoring the redox potential. Solution samples were analysed by ICP-AES and HPLC, and surfaces of residual sulphides analys...

TheMarcona–Mina Justa deposit cluster, hosted by Lower Paleozoic metaclastic rocks and Middle Jurassic shallow marine andesites, incorporates the most important known magnetite mineralization in the Andes at Marcona (1.9 Gt at 55.4% Fe and 0.12% Cu) and one of the few major iron oxide–copper–gold (IOCG) deposits with economic Cu grades (346.6 Mt at 0.71% Cu, 3.8 g/t Ag and 0.03 g/t Au) at Mina ...

We examined the effects of hypoxia and sulphide levels on the ventilatory activity of Arenicola marina and determined whether ventilation compensates for oxygen deficiency and affects the mode of energy provision. A. marina ventilated intermittently, irrespective of ambient P(O2) and sulphide concentration. The ventilation rate was 28.5+/-16 ml h(-1) g(-1) wet mass during normoxia, but increase...

Several Cyprus-type volcanogenic massive sulphide (VMS) deposits occur in the Jurassic ophiolitic series of the Northern Apennines. Stratabound, stratiform and stockwork deposits were formed in the western limb of the Neotethys (Ligurian Ocean) and are observed today in basalt, gabbro and serpentinised peridotite host rocks. The studied stockwork deposit at Boccassuolo occurs in basalt and basa...

The product of the biological sulphate reduction is sulphide. High concentrations of molecular H2S (g) can be inhibitory for microbial activity, especially at a reactor pH of 6 to 7. This paper focuses on the effect of high sulphide concentrations on the sulphate reduction rates. The results of three investigations operating a continuous reactor, a column reactor and batchtest reactors have sho...

hallium (Tl) is an inorganic element found in the earth’s crust at concentrations ranging from 0.3 to 0.6 mg⋅kg (NRCC 1982). Thallium is rarely present as large ore deposits, but can be recovered from sulphide ores of lead, copper, and zinc and may also be associated with cadmium, iron, and potassium minerals such as feldspars and micas. Thallium minerals such as crookesite, hutchinsonite, lora...