Natural Decrease of Dissolved Arsenic in a Small Stream Receiving Drainages of Abandoned Silver Mines in Guanajuato, Mexico

Arsenic release from the abandoned mines and its fate in a local stream were studied. Physicochemical parameters, metals/metalloids and arsenic species were determined. One of the mine drainages was found as a point source of contamination with 309 μg L^?1 of dissolved arsenic; this concentration declined rapidly to 10.5 μg L^?1 about 2 km downstream. Data analysis confirmed that oxidation of As(III) released from the primary sulfide minerals was favored by the increase of pH and oxidation reduction potential; the results obtained in multivariate approach indicated that self-purification of water was due to association of As(V) with secondary solid phase containing Fe, Mn, Ca.     

Acute and Chronic Toxicity of Effluent Water from an Abandoned Uranium Mine

Inactive or abandoned mines represent a significant source of environmental, chemical, physical, and aesthetic impact. Among concerning situations, the occurrence of abandoned or semi-abandoned mine-associated ponds (for sedimentation of solids, for effluent neutralization, or for washing the ore) is a common feature in this type of system. These ponds are a source of contamination for the groundwater resources and adjacent soils, because they lack appropriate impermeabilization. The use of this water for agriculture may also pose chronic risks to humans. In Portugal, these problems have been diagnosed and some remediation projects have been developed. The purpose of our study was to evaluate the acute and chronic toxicity of water samples collected from the aquatic system surrounding an abandoned uranium mine (Cunha Baixa, Mangualde, Central Portugal). The present study focuses on the water compartment, whose toxicity was evaluated by means of standard toxicity assays using two Daphnia species (D. longispina and D. magna). Three different ponds were used in the characterization of the aquatic system from Cunha Baixa mine: a reference pond (Ref), a mine effluent treatment pond (T), and a mine pit pond (M). Metal analyses performed in the water samples from these ponds showed values that, in some cases, were much higher than maximum recommendable values established (especially Al, Mn) by Portuguese legislation for waters for crop irrigation. Acute toxicity was only observed in the mine pit pond, with EC₅₀ values of 28.4% and 50.4% for D. longispina and D. magna, respectively. The significant impairment of chronic endpoints, translated in reductions in the population growth rate for both species, gives rise to concerns regarding the potential risks for aquatic zooplanktonic communities, from local receiving waters, potentially exposed to point source discharges of the treated and nontreated effluent from Cunha Baixa uranium mine.     

Stream pollution by an organomercury compound

Conclusion A GC/MS study of residues in general can be very rewarding as shown by some of our unexpected discoveries, but due to the vast ammount of data collected, the best way to effectively use the technique for routine survey work must be with the aid of an interfaced computer complete with library search capabilities.     

Bioaugmentation-Assisted Phytostabilisation of Abandoned Mine Sites in South West Sardinia

Bioaugmentation-assisted phytoremediation implies the administration of selected plant growth promoting bacteria, which significantly improve plant growth and sequestration of heavy metals. In this work, 184 bacterial strains associated with roots of Pistacia lentiscus were isolated from plants spontaneously growing in the abandoned Sardinian mining areas (SW Sardinia, Italy) and phylogenetically characterised. Twenty-one bacterial isolates were assayed for properties relevant for plant growth promotion and metal tolerance. Five different strains, belonging to the genera Novosphingobium, Variovorax, Streptomyces, Amycolatopsis, Pseudomonas, were selected based on their properties for the greenhouse phytoremediation tests. Among the tested inocula, the strain Variovorax sp. RA128A, able to produce ACC deaminase and siderophore, was able to significantly enhance germination and increase length and weight of shoots and roots. Irrespective of the applied treatment, mastic shrub was able to accumulate Cd, Pb and Zn especially in roots.     

Speciation and Bioavailability of Metals in Sediments from a Stream Impacted by Abandoned Mines in Maoshi Town,Southwest of China

Bulletin of Environmental Contamination and Toxicology - The speciation of metals in surface sediments, as well as metal concentrations in muscle and liver of sharpbelly Hemiculter leucisculus from...     

Flow Cytometric Analysis of DNA Damage in Cotton Rats, Sigmodon hispidus, Inhabiting an Abandoned Colliery Strip Mine

No abstract available.     

Pilot Study of Environmental Monitoring of Konya Region near Abandoned Mercury Mine in Turkey

Abandoned mines are an important global concern and continue to pose potential threats to human health including environmental damage/s. There is not any specific regulation for mining wastes in Turkey and this situation puts the mining wastes into the dangerous category. Therefore, this study focuses on the environmental effects of the abandoned mercury mines. To demonstrate environmental mercury contamination, fish samples were collected from two different regions which were contaminated and uncontaminated region. As a biomarker of environmental exposure the levels of Hg in fish samples were measured by Cold Vapor-Atomic Absorption Spectrometry (CVAAS). In fish samples, the levels of Hg were 0.504 ± 0.475 (mg/kg) (Mean ± SD) in Group 1 and 0.04 ± 0.054 (mg/kg) (Mean ± SD) in Group 2. Our data suggested that although mercury mine was closed long time ago, mining waste is still a problem and continues to contaminate the environment.     

Potential Risks of Effluent from Acid Mine Drainage Treatment Plants at Abandoned Coal Mines

The lethal and sublethal toxicity of effluent from three acid mine drainage treatment plants were monitored from August 2009 to April 2010 using Daphnia magna (reference species) and Moina macrocopa (indigenous species). Acute lethal toxicity was observed in Samma effluent due to incomplete neutralization of acid mine drainages by the successive alkalinity producing system (SAPS). Additionally, there was no significant difference in toxicity values (TU) between D. magna and M. macrocopa (p < 0.05). Toxicity identification results of the final effluent collected in January 2010 showed that Al and Zn were key toxicants in addition to acidic pH. Unlike the Samma effluent, both Hwangji and Hamtae effluent had pH values that were near neutrality and showed either no acute toxicity or toxicity values less than 1 TU. However, the feeding rates of D. magna and M. macrocopa were significantly reduced when compared to the control (p < 0.05). These findings suggest that the Hamtae and Hwangji effluent likely have a sublethal effect on aquatic organisms in receiving water bodies.     

Geo-Spatial Characterization of Soil Mercury and Arsenic at a High-Altitude Bolivian Gold Mine

Soil mercury concentrations at a typical small-scale mine site in the Bolivian Andes were elevated (28–737 mg/kg or ppm) in localized areas where mercury amalgams were either formed or vaporized to release gold, but was not detectable beyond approximately 10 m from its sources. Arsenic was measurable, exceeding known background levels throughout the mine site (77–137,022 ppm), and was also measurable through the local village of Ingenio (36–1803 ppm). Although arsenic levels were high at all surveyed locations, its spatial pattern followed mercury, being highest where mercury was high.     

石门雄黄矿附近地区慢性砷中毒流行病学特征

为研究石门雄黄矿附近地区人群慢性砷中毒的患病率及其分布特点,采用现况调查研究方法,以雄贡矿排放洗矿水河流下游的三个村庄为污染区,另选一个远离矿区无污染的村庄为对照,每个村子各选取在当地居住五年以上,无职业性砷接触史的居民约２００人,进行体检并填写健康调查问卷。