Until recently, the earth had seven continents. To that number, humans have added an eighth — an amorphous, floating mass of waste plastic trapped in a gyre of currents in the north Pacific, between Hawaii and Japan. Researchers have estimated that this garbage patch may contain as much as 100 million tons of plastic debris and is perhaps twice the size of Texas, if not larger.
Across the world’s oceans there are still many more millions of tons of floating plastic, most of it originating from land, not ships. All of this solid waste is bad news. It traps as many as a million seabirds every year, as well as some 100,000 marine mammals.
Now comes what could be more bad news. A new study, announced at a recent meeting of the American Chemical Society, suggests that plastics in seawater break down faster than expected. As they do, they apparently release contaminants, including potentially harmful styrene compounds not normally found in nature. This was not merely a laboratory finding. The author of the study, Katsuhiko Saido, a scientist at Nihon University in Japan, found the same chemical compounds in seawater samples collected near Malaysia, the Pacific Northwest, and in the northern Pacific.
The effects of these broken-down plastics on marine organisms is as yet unknown, and they will be harder to measure than the damage that plastic refuse does to sea-life. But adding to the contaminant load of the oceans cannot be a good thing.
What we are seeing here is yet another of the large-scale, potentially tragic, uncontrolled experiments that humans have conducted on their environment without intending to. And though we cannot do much about the millions of tons that have already been sent to sea, we can at least begin to ask ourselves, when we get ready to pitch a plastic container, where is this likely to end up?
Tidak ada komentar:
Posting Komentar