Since the 1980s, China has been importing recyclable wastes from other countries to address resource shortages. As a result, I saw in the news that there was a great deal of waste in recycled waste and Korea is suffering from fine dust. I was shocked by the news that the garbage island was 15 times the size of the Korean peninsula.
A new study traces the contamination of fertilizer back to household and supermarket waste
Contamination close-up
I also need to find more articles about the great Pacific garbage patch.
중국은 1980년대 이후 자원 부족 문제를 해결하기 위해 다른 나라로부터 재활용할 수 있는 폐기물을 수입해왔지만 2017년 전격 수입 중단을 선언했습니다. 이로 인해 한국은 재활용 쓰레기에 대란이 일어났다고 뉴스에서 보았다. 미세먼지로 고통받는 한국 뉴스로 환경에 생각도 달라졌었는데 또다른 뉴스는 쓰레기섬이 한구의 15배 크기라는 기사를 보고 충격을 받았다. the great Pacific garbage patch가 무엇인지 좀더 기사도 찾아봐야겠다.
Composting waste is heralded as being good for the environment. But it turns out that compost collected from homes and grocery stores is a previously unknown source of microplastic pollution, a new study April 4 in Science Advances reports.
This plastic gets spread over fields, where it may be eaten by worms and enter the food web, make its way into waterways or perhaps break down further and become airborne, says Christian Laforsch, an ecologist at the University of Bayreuth in Germany. Once the plastic is spread across fields, “we don’t know its fate,” he says.
That fate and the effects of plastic pollution on land and in freshwater has received little research attention compared with marine plastic pollution, says ecologist Chelsea Rochman of the University of Toronto. Ocean microplastics have gained notoriety thanks in part to coverage of the floating hulk of debris called the great Pacific garbage patch (SN Online: 3/22/18).
But current evidence suggests that plastic pollution is as prevalent in land and freshwater ecosystems as it is in the oceans, where it’s found “from the equator to the poles,” says Rochman, author of a separate commentary on the state of plastic pollution research published in the April 6 Science. Plastic “is seen in the high Arctic, where we suspect it comes down in rain. We know it’s in drinking water, in our seafood and spread on our agricultural fields,” she says.
Laforsch and his colleagues looked at several different kinds of biowaste that’s composted and spread on farmland in Germany, including household compost and grass clippings, supermarket waste and grain silage leftover from biogas production.
Compost samples taken from supermarket waste contained the greatest amount of plastic particles, with 895 pieces larger than 1 millimeter found per kilogram of dry weight. Household compost in contrast contained 20 and 24 particles per kg of dry weight, depending on the size of the sieves used to sift the compost. The detritus included bits of polyester and a lot of styrene-based polymers, commonly used in food packaging. Almost no particles were found in samples of silage from biogas production.
Contamination close-up
A variety of microplastics collected from composted waste in Germany included polyethylene spheres (A), which are used in paints and coatings; PVC fragments (B), used widely in construction materials, electronics and vehicles; bits of polyethylene (C and D), which is found in bags, containers and bottles; polyester fibers (E); and polypropylene (F), used in bags, packaging and textiles.
“I never thought about plastic in compost ending up as fertilizer. But when you think about it, it makes sense,” says environmental scientist Ad Ragas of Radboud University in Nijmegen, The Netherlands, who wasn’t involved in the work. A crate of rotting cucumbers wrapped in plastic that gets chucked, those stickers on every tomato in a bunch — that packaging doesn’t disappear.
Ragas says compost probably doesn’t contribute as much plastic to the environment as other sources, such as sewage treatment plant sludge, which contains polyester debris from clothes washers, and runoff from streets, which can be loaded with particles of synthetic rubber used in tires. But the compost contribution deserves investigation, Ragas says. “This triggers a lot of questions we haven’t studied yet.”
Those questions include possible effects on different organisms, from plants to earthworms to birds to people, Rochman says. Those effects will likely differ depending on the kind of plastic, which varies depending on its starting polymer and the additives used to impart certain qualities such as flexibility, sturdiness or durability under ultraviolet light.
“We are not saying we should get rid of all plastics,” Rochman says. “But we do need to start thinking of plastics as a persistent global pollutant.”
📝 Story Sorce : BY RACHEL EHRENBERG
📝 Story Sorce : BY RACHEL EHRENBERG
https://www.sciencenews.org/article/microplastics-may-enter-freshwater-and-soil- compost
📚 Reference
C.M. Rochman. Microplastics research — from sink to source.
Science. Vol.360, April 6, 2018, p. 28. doi: 10.1126/science.aar7734.
N. Weithmann et al. Organic fertilizer as a vehicle for the entry of microplastic into the environment.
Science Advances. Published online April 4, 2018. doi:10.1126/sciadv.aap8060.
📖 Further Reading
Science News Online, March 22, 2018.
Science News. Vol.189, February 20, 2016, p. 20.
Comments