Anchorage/Leipzig. Contaminants from natural coal deposits in the Gulf of Alaska are not easily bioavailable, unlike the crude oil from the Exxon Valdez tanker catastrophe. This clearly disproves the theory that natural coal deposits were the cause of observed environmental damage. PAH pollutants were blamed for the continuing degradation of the ecosystem off the coast of Alaska. Then a dispute erupted over the origins of these pollutants in science. According to an international team of researchers writing in specialist journal "Environmental Science & Technology", the crude oil from the Exxon Valdez was the main source of the bioavailable PAH contaminants.
The scientists from Tennessee Technological University, the University of Lausanne, Calvin College and the Helmholtz Centre for Environmental Research (UFZ) compared polycyclic aromatic hydrocarbons (PAHs) in samples of tanker oil and from coal deposits. Their investigation with bacterial biosensors has now shown that only the PAHs from the tanker oil had any effect on organisms.
The scientists were able to prove this in the lab with the help of genetically engineered bacteria which react with the contaminants. "These biosensors are based on bacteria which feed on polycyclic aromatic hydrocarbons. If these bacteria come into contact with these substances, it flips a biological switch and the bacteria start to glow", explains Prof. Hauke Harms from the UFZ. "There are clear advantages to this new forensic application: there is no need to take the indirect route of costly chemical analysis to prove results." As the bacteria used give off a great deal of light, the scientists are able to study the processes at a high resolution - down to a microscopic level in individual organisms.
Polycyclic aromatic hydrocarbons are a natural component of coal and petroleum. Because of their longevity and toxicity, sixteen of these substances were classed as particularly hazardous environme
|Contact: Tilo Arnhold|
Helmholtz Association of German Research Centres