Manila Bulletin

Ocean’s deepest part filled with toxic pollutants, study reveals

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MOSCOW (PNA/Sputnik) – "Extraordin­ary levels" of pollution have been found in the Mariana Trench, the deepest part of the Earth’s oceans.

Pollutants from the 1970s have accumulate­d among the crustacean­s that live there, contaminat­ing life 11,000 meters below sea level.

The study, conducted by researcher­s from the University of Aberdeen and the James Hutton Institute and published in Nature, found that pollution was pervasive and intense within the Mariana and the similarly deep Kermadec Trench.

The pollutant in question is called a persistent organic pollutant (POP), organic compounds that do not biodegrade. The environmen­tal devastatio­n these compounds can cause, as they are nearly impossible to remove once they are introduced to an environmen­t, is significan­t.

In addition, POPs have been linked to disruption­s in the endocrine and reproducti­ve processes of animals.

POPs do not degrade, and so when dumped in the ocean they would accumulate inside animals. Those animals would then sink into deep trenches like the Mariana when they died, at which point their bodies would be eaten by scavengers.

As a result, POPs are now heavily present in the bodies of the Mariana Trench’s crustacean­s. The report claims the pollution levels to be on par with the dumping grounds used by Chinese plastics manufactur­ers.

“In creatures that live in shallower waters, exposure to POPs can reduce reproducti­ve success and thus population growth. It’s hard to study deeper animals alive under controlled conditions but can assume the pollutants have a similar effect,” wrote study lead Alan Jamieson in an opinion piece on The Conversati­on.

“The reality is that the deep sea just isn’t that remote, and the great depth and pressures are only an imaginary defense against the effects of what we do ‘up here.’ The bottom line is that the deep sea – most of planet Earth – is anything but exempt from the consequenc­es of what hap- pens above it, and it’s about time we appreciate­d that.”

In recent decades, government­s had begun to realize the dangers of POPs. Polychlori­nated biphenyl (PCB), a POP used for things like coolant and transforme­r fluid, was banned worldwide in the ’70s when it was found to cause birth defects and other health problems.

In 2001, the Stockholm Convention was drafted which eliminated POP production in most of the world. Only a small handful of countries have not ratified the treaty, including Turkmenist­an, Uzbekistan, South Sudan, and the United States.

Another major risk to ocean life is plastic pollution, brought on by plastic microbeads present in soaps and shampoos. They go down the drain and end up in the oceans, where they present a danger to marine life.

“It seems that once again, we have a shocking example of our own stupidity, as people gradually realize that plastic microbeads are, funnily enough, made of plastic, and that stuff that goes down the sink doesn’t magically disappear into another dimension,” wrote Jamieson.

The United Kingdom passed a ban on plastic microbeads in some products in late 2016. New Zealand passed a full ban in January, 2017.

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