Tuesday, August 24, 2010

Gold mining largest source of anthropogenic arsenic

Gold mining is by far the largest single source of anthropogenic arsenic

By S. U. Dani, August 24, 2010

Table 1 shows that gold mining is by far the largest single source of world anthropogenic arsenic. If all estimated gold reserves are exploited, then gold mining will release estimated 104 million tonnes of arsenic in the environment. This is more than 20 times as much arsenic as has been released from all anthropogenic sources in the industrial age so far.

Monday, August 23, 2010

Subchronic arsenic toxicity in rats

Environ Toxicol. 2010 Aug 19. [Epub ahead of print]

Pathological, immunological and biochemical markers of subchronic arsenic toxicity in rats

Nain S, Smits JE.

Ecosystem & Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4Z6.


Subchronic exposure to arsenic in rats was investigated to identify sensitive indicators of subclinical toxicity in rats. Immunological, pathological, and biochemical bioindicators were examined in rats exposed to arsenic in their drinking water. Juvenile male Wistar rats were allocated to four treatment groups receiving 0, 0.4, 4, and 40 ppm of arsenite in drinking water for 18 wks. Besides daily monitoring for clinical signs of adverse health effects, clinical biochemistry, B-cell-mediated and innate immune responses, plus gross, and histopathology were examined. In vitro tests of oxidative damage to basic cellular constituents, lipids, proteins, and nucleic acids, were measured using thiobarbituric acid reacting substances (TBARS) assays, protein carbonyl formation, and 8-hydroxydeoxyguanosine (8-OHdG), respectively. Clinical changes in the rats were limited to decreased feed and water intake in the high- (40 ppm) dose group (P < 0.05), however, growth rate was not affected. Serum biochemical changes occurred in blood urea nitrogen, K(+), Cl(-), and alanine aminotransferase (ALT) from arsenic exposure. Immunotoxicity was evident through a dose-dependent suppression of the secondary antibody-mediated response to a T-cell-dependent antigen, keyhole limpet hemocyanin (KLH). Histopathology of the liver revealed marked fatty infiltration and vacuolization particularly evident in periacinar hepatocytes. This pattern of toxicopathology in the high-exposure group may be related to the significantly higher (P < 0.05) oxidative stress, demonstrated through lipid peroxidation (TBARS assay) in the rats exposed to 40 ppm arsenite. The present study revealed that young, growing rats exposed to arsenic for 18 wks tolerated exposures up to 4 ppm. At higher doses, there was evidence of hepatotoxicity, humoral immunity was compromised, and an adverse effect on hepatic organelle and cell membranes was evident through a dose dependent increased in oxidative stress. (c) 2010 Wiley Periodicals, Inc. Environ Toxicol, 2010.

Monday, August 16, 2010

Oil spills raise arsenic levels in the ocean

Imperial College London News Release
For Immediate Release:
Friday 2 July 2010

Oil spills raise arsenic levels in the ocean, says new research

Oil spills can increase levels of toxic arsenic in the ocean, creating an additional long-term threat to the marine ecosystem - News Release

Sunday, August 15, 2010

Opencast coal mines in England

BBC News
15 August 2010 Last updated at 06:30 GMT

More opencast mine bids 'likely on greenfield sites'

Applications for opencast mining on greenfield sites are likely to increase to meet the UK's demand for energy, the British Geological Survey has said.

Mountain mining damages streams

Published online 9 August 2010 | Nature 466, 806 (2010) | doi:10.1038/466806a

Mountain mining damages streams

Study shows that stripping mountains for coal has a much greater impact than urban growth.

Natasha Gilbert
Pittsburgh, Pennsylvania

West Virginia’s mountains contain valuable low-sulphur coal. Photograph: P. Souza/Chicago Tribune/MCT/Newscom

The controversial practice of stripping off the tops of mountains to mine coal, long suspected of polluting streams, is guilty as charged, scientists say.