A new species of heavy metal Tolerant Bacterium from the Dabaoshan Mining Area in Guangdong Province, China.

Heavy metal extraction is a notorioulsy high pollution risk industry, as the metals are highly toxic to most forms of life, and most extraction techniques involve extracting them from ores using acids or other toxic materials (e.g. mercury), creating a toxic sludge, which, if it escapes into the environment, can prove extremely harmful to waterways and agricultural land, as well as presenting a high risk to human health. This has led to a great deal of interest in bioremediation techniques which use micro-organisms to extract the metals from ores, and a consequent search for suitable organisms.

In a paper published in the journal PLoS One on 4 December 2012, Honghui Zhu, Jianhua Guo, Meibiao Chen and Guangda Feng of the Guangdong Open Laboratory of Applied Microbiology at the State Key Laboratory of Applied Microbiology and Qing Yao of the South China Agricultural University, describe a new species of cadmium tollerant Bacterium from the Dabaoshan Mining Area in Guangdong Province, China.

The new species is placed in the genus Burkholderia, several species of which have proved to be highly tollerant to heavy metals, and useful in bioremediation, and have apparently evolved several different biochemical methods for doing this, and is given the specific name dabaoshanensis, meaning 'from Dabaoshan'.

Transmission electron micrograph of Burkholderia  dabaoshanensis. Zhu et al. (2012).

Burkholderia  dabaoshanensis is a rod-shaped, non-spore-forming gram negative Bacterium, 1.3-1.8 µm in length and 0.5-0.6 µm in diameter. It is aerobic (i.e. respires oxygen) and weekly motile (it can move itself, though not very well). It was found living in highlt acidic (pH2-4) soils contaminated with heavy metals, particularly cadmium. In the laboratory it was able to grow and form colonies in media of pH 4-9 (sugesting that at pHs of less than 4 it survives but remains dormant), at temperatures of 5-40˚C, but did best at an optimum condidions of pH6 and 30˚C. It is resistant to streptomycin, kanamycin, ampicillin and cefetamet. 

See also The ten most polluted places on Earth, Three new species of Diatom from Mountain Lakes in Washington State, USA, Two new species of Amphisphaerid Fungi from southern China, Four new species of fossil Diatom from the western United States and Cadmium spill on Longjiang River threatens water supplies to several Chinese cities.

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Cadmium spill on Longjiang River threatens water supplies to several Chinese cities.

On 15 January 2012 authorities in Guangxi Province in Southern China detected high levels of cadmium metal in the Longjiang River, after investigating reports of hundreds of dead fish in Hechi City. Cadmium levels were reported to be about 0.025 mg/l­ˉ³ (0.025 milligrams per liter) five times the official permitted safety levels. Cadmium, which is used in batteries, poses a serious threat to health; it is a carcinogen and can cause damage to the kidneys, liver, respiratory system and skeleton, and can be a persistent pollutant in water systems as it is hard to flush out. As well as Hechi the spill threatens the water supplies of Luijiang and Luizhou cities, with populations of 1.5 and 3.7 million respectively. There are reports of panic-buying of bottled water in Luijiang, and it is unclear if the 350 000 tons of water held in underground reserves at Luizhou would be enough to ride out the crisis. At the time of writing there have not been any reports of poisoning due to the incident.

The location of the Longjiang River, with the area effected by the spill highlighted in red. Zhang Ye/China Daily.

Authorities responded by releasing 500 million cubic meters of water from the Honghua Hydropower Station and mobilizing Police and Army personnel to pour polyaluminium chloride into the river as a neutralizing agent.

Officers from the Liuzhou brigade of the Armed Police Force pouring polyaluminium chloride into the Lomgjiang River on 29 January 2012. Xinhua News Agency.

On 25 January officials began investigating the Guangxi Jinhe Mining Co. in Hechi as the most likely source of the contamination. The company mines zinc in the city, and has failed repeatedly failed government inspections of its waste disposal procedures. Since cadmium is a common by-product of zinc mining the mine was an obvious target for suspicion. However 31 January local environment officials released a statement to the effect that they had arrested seven executives from chemical plants in Guangxi. It is unclear if this means the Jinhe Mine has been exonerated, if the investigation has been widened, or if officials are being deliberately vague to avoid prejudicing any future prosecution. Officials have also reported that seven mines and factories in have been closed as a precaution.

An environment official collecting samples from the Longjiang River in Luizhou. Reuters.

In the past three decades China has undergone an unprecedented process of industrialization, and has suffered many environmental problems as a consequence. In the past environmental groups have accused the country of turning a blind eye to environmental issues, in order to promote economic growth. However in the past few years Chinese authorities have shown signs of taking the environment much more seriously, after a string of pollution incidents with health implications, which have lead to public outcries.

See also Acid spill from gold mine adds to Edith River's woes, Copper spill causes pollution alert on the Edith River in the Northern Territory, Nine killed at illegal rare-earth mine in Guangxi Zhuang Autonomous Region, At least 21 miners killed in mining disaster in Yunnan Province and River Neath turned orange by mining run-off.