永利皇宫官方网站:Spanish dilemma

 作者:蹇搬     |      日期:2019-03-08 10:10:02
By Luis Miguel Ariza in Madrid THE tens of thousands of tonnes of toxic metals deposited near Doñana National Park in Spain after a dam at a mine collapsed could be removed using genetically engineered plants. This suggestion, which has horrified environmentalists, was made at a meeting in Seville two weeks ago to decide how to deal with the pollution caused by the seven million tonnes of toxic mud that spread along the Guadalquivir River last year. Most of it has been mechanically removed, but heavy metals—including lead, copper and arsenic—have leached into the soil to a depth of 20 centimetres. Victor de Lorenzo of the National Centre of Biotechnology in Madrid wants to remove the pollution with plants genetically engineered to suck more metals out of the soil. However, environmentalists headed by Greenpeace say that no one yet knows how bioengineered plants might affect the ecosystem. Some scientists claim that natural plants and microorganisms would be just as effective. Pilar Bernal of the Centre for Agronomic Research in Murcia suggested that one hectare of the wild herb Alpine pennycress (Thlaspi caerulescens) could dispose of about 130 kilograms of zinc a year. The snag is that introducing foreign plants might also upset the local ecosystem. “You have to be very careful how you select candidates, as we are talking about a natural reserve,