Spread of pollution

 作者:拓跋卸     |      日期:2019-03-07 06:13:00
By Emma Young Butter could be the key to tracking levels of air pollution around the world, say British researchers from Lancaster University and Greenpeace Research Laboratories. Kevin Jones, at Lancaster, says analysing pats of butter from individual farms could be a reliable way of monitoring local production of pollutants such as PCBs, dioxins and pesticides – especially in countries without sophisticated air monitoring technology. Air pollutants fall on grazing pastures and become concentrated in the fat in cow’s milk, which is itself concentrated in butter, says Jones. “Almost every country in the world has enough cows to make the butter testing possible,” he told New Scientist. “There are huge areas of the world where no measurements are currently made at all. So testing butter could allow fairly accurate measures to be simply made.” The test could be used to measure the success of a UN programme launched last December to eliminate the production of 12 ‘persistant organic pollutants’ (POPs) from 122 countries worldwide, says the team (Pollutant ban). Jones’s team analysed more than 60 samples of butter from 23 countries, including the UK, China and Africa. They measured levels of polychlorated biphenyls (PCBs), which are often used as lubricants, and pesticides. Their data closely matched that produced by sophisticated air monitoring centres in some of these countries, says Jones. He accepts that the technique has certain limitations. In some countries, cows are kept inside for several months each year. This would reduce their exposure to air pollutants and produce deceptively low pollution scores. The frequent transport of dairy animals nationally and internationally could also blur the results. But the time delay between a cow being exposed to high levels of pollutants and those pollutants showing up in milk is just a few days, says Jones. More at: Environmental Science and Technology (vol 35,