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Asian Geographic - - Front Page -

Weiqi

Ori­gin: China Coun­tries: World­wide, es­pe­cially Japan and Korea

Plas­tic nanopar­ti­cles – tiny pieces of plas­tic less than 1 mi­crome­tre in size – could po­ten­tially con­tam­i­nate food chains, and ul­ti­mately af­fect hu­man health, ac­cord­ing to a re­cent study by sci­en­tists from the Na­tional Univer­sity of Sin­ga­pore (NUS). They dis­cov­ered that nanoplas­tics are eas­ily in­gested by marine or­gan­isms and ac­cu­mu­late in­side them, pos­ing a risk of be­ing trans­ferred up the food chain and threat­en­ing food safety.

Ocean plas­tic pol­lu­tion is a huge and grow­ing global prob­lem. It is es­ti­mated that the oceans may al­ready con­tain over 150 mil­lion met­ric tonnes of plas­tic, and each year, about eight mil­lion met­ric tonnes of plas­tic will en­ter the ocean. Plas­tics do not de­grade eas­ily: In the marine en­vi­ron­ment, they are usu­ally bro­ken down into smaller pieces by the sun, waves, wind and mi­cro­bial ac­tion. These mi­cro- and nanoplas­tic par­ti­cles in the wa­ter may be in­gested by fil­ter-feed­ing marine or­gan­isms such as bar­na­cles, tube worms and sea squirts.

Us­ing the acorn bar­na­cle Am­phibal­anus am­phitrite as a model or­gan­ism, the NUS re­search team demon­strated for the first time that nanoplas­tics con­sumed dur­ing the lar­val stage are re­tained and ac­cu­mu­lated in­side the bar­na­cle lar­vae un­til they reach adult­hood.

“We opted to study acorn bar­na­cles as their short life cy­cle and trans­par­ent bod­ies made it easy to track and vi­su­alise the move­ment of nanoplas­tics in their bod­ies within a short span of time,” said Mr Sa­marth Bhar­gava, a PHD stu­dent from the De­part­ment of Chem­istry at the NUS Fac­ulty of Science.

The re­search team in­cu­bated the bar­na­cle lar­vae in so­lu­tions of their reg­u­lar feed cou­pled with plas­tics that are about 200 nanome­tres in size with green flu­o­res­cent tags. The lar­vae were ex­posed to two dif­fer­ent treat­ments: “acute” and “chronic”.

Un­der the “acute” treat­ment, the lar­vae were kept for three hours in a so­lu­tion that con­tained 25 times more nanoplas­tics than cur­rent es­ti­mates of what is present in the oceans. On the other hand, in the “chronic” treat­ment, the bar­na­cle lar­vae were ex­posed to a so­lu­tion con­tain­ing low con­cen­tra­tions of nanoplas­tics for up to four days. ABOVE Bar­na­cles are a type of arthro­pod that live in shal­low and tidal wa­ters, at­tach­ing them­selves per­ma­nently to a hard sub­stra­tum. Shown here are bar­na­cle lar­vae (mag­ni­fied)

RIGHT

A re­search team from NUS has dis­cov­ered that nanoplas­tics are eas­ily in­gested by bar­na­cle lar­vae and can ac­cu­mu­late in their bod­ies over time

BE­LOW Ocean plas­tic pol­lu­tion is a grow­ing global prob­lem

The lar­vae were sub­se­quently fil­tered from the so­lu­tion and ex­am­ined un­der a mi­cro­scope. The dis­tri­bu­tion and move­ment of the nanoplas­tics were mon­i­tored by ex­am­in­ing the flu­o­res­cence from the par­ti­cles present within the lar­vae over time.

“Our re­sults showed that af­ter ex­pos­ing the bar­na­cle lar­vae to nanoplas­tics in both treat­ments, the lar­vae had not only in­gested the plas­tic par­ti­cles, but the tiny par­ti­cles were found to be dis­trib­uted through­out the bod­ies of the lar­vae,” said Ms Se­rina Lee from the Trop­i­cal Marine Science In­sti­tute at NUS.

Even though the bar­na­cles’ nat­u­ral waste re­moval path­ways of moult­ing and ex­cre­tion re­sulted in some re­moval of the nanoplas­tics, the team de­tected the con­tin­ued pres­ence of nanoplas­tics in­side the bar­na­cles through­out their growth un­til they reached adult­hood.

“Bar­na­cles may be at the lower lev­els of the food chain, but what they con­sume will be trans­ferred to the or­gan­isms that eat them. In ad­di­tion, plas­tics are ca­pa­ble of ab­sorb­ing pol­lu­tants and chem­i­cals from the wa­ter. These tox­ins may be trans­ferred to the or­gan­isms if the par­ti­cles of plas­tics are con­sumed, and can cause fur­ther dam­age to marine ecosys­tems and hu­man health,” said marine bi­ol­o­gist Dr Neo Mei Lin from the Trop­i­cal Marine Science In­sti­tute at NUS.

The team’s re­search find­ings were first pub­lished on­line in the jour­nal ACS Sus­tain­able Chem­istry & En­gi­neer­ing in March 2018. The study was funded un­der the Marine Science Re­search and Devel­op­ment Pro­gramme of the Na­tional Re­search Foun­da­tion Sin­ga­pore.

The NUS re­search team seeks to fur­ther their un­der­stand­ing of the translo­ca­tion of nanopar­ti­cles within the marine or­gan­isms and po­ten­tial path­ways of trans­fer in the marine ecosys­tem.

“The life span and fate of plas­tic waste ma­te­ri­als in (the) marine en­vi­ron­ment is a big con­cern at the mo­ment ow­ing to the large amounts of plas­tic waste and its po­ten­tial im­pact on (the) marine ecosys­tem and food se­cu­rity around the world. The team would like to ex­plore such top­ics in the near fu­ture and pos­si­bly (...) come up with path­ways to ad­dress such prob­lems,” ex­plained As­so­ciate Pro­fes­sor Suresh Valiyaveet­til from the De­part­ment of Chem­istry at the NUS Fac­ulty of Science, who co-su­per­vised the re­search. ag

“Bar­na­cles may be at the lower lev­els of the food chain, but what they con­sume will be trans­ferred to the or­gan­isms that eat them”

Yangtze River

Asia’s long­est river The river basin is home to nearly 500 mil­lion peo­ple Flows into the Yel­low Sea Car­ries the most plas­tic waste to the ocean – 1.5 mil­lion met­ric tonnes!

Amur River

• Orig­i­nates in north­east­ern China, form­ing a sig­nif­i­cant part of the bor­der be­tween Hei­longjiang prov­ince (China) and Siberia (Rus­sia); flows into the Sea of Okhotsk

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