terça-feira, 14 de fevereiro de 2017

Poluição do fundo do mar estudada (e perdura por décadas aparentemente)

(os estudos tipicamente analisam até 2000m, este não):
http://www.nature.com/articles/s41559-016-0051

Citando:

  • "POPs were released into the environment through industrial accidents and discharges, leakage from landfills, or incomplete incineration 7 . Two key POPs are polychlorinated biphenyls (PCBs, used as dielectric fluid) and polybrominated diphenyl ethers (PBDEs, used as flame retardants). From the 1930s to when PCB production ceased in the 1970s, the total global production was ~1.3 million tonnes 8 . Approximately 65% is thought to be contained in landfills or still within electrical equipment, with the other 35% residing in coastal sediments and open oceans 9 . These pollutants are invulnerable to natural degradation 10 and so persist in the environment for decades. Moreover they can spread great distances, including to seemingly isolated environments, such as polar regions and the open ocean 3 .

Pollutants entering the deep sea are deposited in sediments and can readily accumulate in the food chain 11 . Studies on deep-sea organisms have reported higher concentrations than in nearby surface-water species 11,12 . However, although these studies are described as ‘deep sea’, they rarely extend beyond the continental shelf (<2,000 m), so contamination at greater distances from shore and at extreme depths is hitherto unknown."

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