The Asian Age - - Discourse - DR MAHUA SAHA The au­thor is Se­nior Sci­en­tist at Coun­cil for Sci­en­tific and In­dus­trial Re­search- Na­tional In­sti­tute of Oceanog­ra­phy, Goa


Plas­tic not only takes years to de­com­pose in our en­vi­ron­ment but rarely does it fully dis­ap­pear. Im­por­tant that as cit­i­zens we take ac­tion and change our con­sump­tion pat­terns in favour of al­ter­na­tives to plas­tics so that we can min­imise ex­po­sure to harm­ful ad­di­tives and help our en­vi­ron­ment.

From the ice- cov­ered Arc­tic to the trop­i­cal wa­ters of the Pa­cific, all of Earth’s oceans share one thing in com­mon: plas­tic pol­lu­tion.

Dis­carded plas­tic bags, cups, and bot­tles make their way into the sea. To­day, it seems that no part of the ocean is safe from plas­tic trash. The global pro­duc­tion of plas­tics has in­creased from 1.5 mil­lion tonnes in 1950 to 299 mil­lion tonnes in 2013, rep­re­sent­ing a four per­cent in­crease over 2012. Their use has in­creased 20- fold in the past half­cen­tury and is ex­pected to dou­ble again in the next 20 years.

To­day nearly every­one ev­ery­where ev­ery day comes into con­tact with plas­tics – es­pe­cially plas­tic pack­ag­ing. For those of us work­ing in the sus­tain­able ma­te­ri­als man­age­ment space, we’ve un­der­stood for a long time that plas­tic pol­lu­tion in the world’s oceans has been cat­a­strophic.

A part of plas­tics waste reaches the ocean through dif­fer­ent path­ways, and pol­lutes the marine en­vi­ron­ment due to waste mis­man­age­ment and coastal and marine ac­tiv­i­ties. Plas­tic that is dumped in rivers and then ends up in the world’s oceans is one of the ma­jor sources of marine pol­lu­tion, whereas Asian wa­ter­ways are the ma­jor car­ri­ers.

Ac­cord­ing to re­searchers at The Ocean Cleanup, a Dutch foun­da­tion, rivers carry an es­ti­mated 1.15- 2.41 mil­lion tonnes of plas­tic into the sea ev­ery year, an amount that needs be­tween 48,000 to over 100,000 dump trucks to carry it away.

The Yangtze, the world’s third­longest river, “is the largest con­tribut­ing catch­ment” dump­ing some 330,000 tonnes of plas­tic into the East China Sea, which is fol­lowed by the Ganges River. In a study pub­lished in Science jour­nal, around 192 coun­tries whose coast­lines are bor­dered by the At­lantic, Pa­cific and In­dian Oceans, Mediter­ranean and Black Seas, pro­duced a to­tal of 2.5 bil­lion met­ric tons of solid waste. Of that, 275 mil­lion met­ric tons was plas­tic, and an es­ti­mated 8 mil­lion met­ric tons of mis­man­aged plas­tic waste en­tered the ocean in 2010.

Plas­tics in the marine en­vi­ron­ment are of in­creas­ing con­cern be­cause of their per­sis­tence and ef­fects on oceans, wildlife, and es­pe­cially on hu­mans. Several broad classes of plas­tics are used in pack­ag­ing: Polyethye­lene ( PE), Polypropy­lene ( PP), Polystyrene ( PS), Poly­eth­yl­ene tereph­tha­late ( PET) and Polyvinyl chlo­ride ( PVC). A re­cent sig­nif­i­cant find­ing is that minute frag­ments of plas­tic de­bris, termed mi­croplas­tics, oc­cur in oceans world­wide.

Mi­croplas­tics, a form of man­made lit­ter, have been ac­cu­mu­lat­ing in the oceans at least for the last four decades. Mi­croplas­tics pol­lu­tion is ev­i­dently a ma­jor con­cern when talk­ing about en­vi­ron­men­tal pro­tec­tion in light of hu­man de­vel­op­ment.

Mi­croplas­tics are par­ti­cles less than five mm in size that de­te­ri­o­rate from larger plas­tic pieces that have en­tered the oceans. Mi­croplas­tics come from a va­ri­ety of sources, in­clud­ing from larger plas­tic de­bris that de­grades into smaller and smaller pieces.

In ad­di­tion, mi­crobeads, a type of mi­croplas­tic, are very tiny pieces of man­u­fac­tured poly­eth­yl­ene plas­tic that are added as ex­fo­liants to health and beauty prod­ucts, such as some cleansers and tooth­pastes. These tiny par­ti­cles eas­ily pass through wa­ter fil­tra­tion sys­tems and end up in the ocean, pos­ing a po­ten­tial threat to aquatic life. Ac­cord­ing to a 2012 sur­vey, 4,360 tons of mi­crobeads were used through­out all Euro­pean Union coun­tries in that year alone.

In the light of grow­ing ap­pre­hen­sion re­gard­ing ocean pol­lu­tion, and con­sid­er­ing the broad range of prod­ucts from which this pol­lu­tion orig­i­nates, it is no sur­prise that tiny plas­tic par­ti­cles can ac­cu­mu­late to such quan­ti­ties as 93- 236 thou­sand tons float­ing in the oceans as pre­dicted by a re­cent study in En­vi­ron­men­tal Re­search Let­ters. It is con­cern­ing, how­ever, that this amount is 37 times greater than pre­vi­ous es­ti­mates be­cause it speaks to just how much more abun­dant these per­sonal care prod­ucts are be­com­ing, and how much of an im­pact they can re­al­is­ti­cally have on marine wildlife.

Ow­ing to their small size, mi­croplas­tics are con­sid­ered bioavail­able to or­gan­isms through­out the food- web. Their com­po­si­tion and rel­a­tively large sur­face area make them prone to ad­her­ing to wa­ter­borne or­ganic pol­lu­tants ( e. g. POPs) and to leach­ing of plas­ti­cis­ers that are con­sid­ered toxic. POPs, the haz­ardous hu­man- made chem­i­cal that oc­curs uni­ver­sally in sea wa­ter at very low con­cen­tra­tions, are picked up by mi­croplas­tics via par­ti­tion­ing and the hy­dropho­bic­ity of POPs fa­cil­i­tate their con­cen­tra­tion in the mi­croplas­tic lit­ter.

Fur­ther, plas­tics con­tain ad­di­tives and chem­i­cals that are added to im­prove the de­sir­able prop­er­ties of the plas­tic prod­uct, for ex­am­ple, an­tiox­i­dants, light- sta­bilis­ers, slip ad­di­tives, etc which may leach out un­der con­di­tions of use and ac­cu­mu­late in the en­vi­ron­ment and grad­u­ally end up in­trud­ing into the food web.

Inges­tion of mi­croplas­tics may there­fore be in­tro­duc­ing tox­ins to the base of the food chain, from where there are po­ten­tial pos­si­bil­i­ties of bioac­cu­mu­la­tion. Mi­croplas­tics can be con­sumed by a di­verse ar­ray of marine or­gan­isms, across trophic lev­els, in­clud­ing zoo­plank­ton, bi­valves, bar­na­cles, fish, tur­tles and birds. Over 220 dif­fer­ent species have been found to con­sume mi­croplas­tic de­bris in na­ture.

In our pre­lim­i­nary study, mi­croplas­tics were found in the beaches of Mum­bai, Goa and Chen­nai in a mod­er­ate level. Re­search in this arena has taken a huge leap re­cently; but un­for­tu­nately in the In­dian scene, only few re­ports are avail­able. It is ex­pected that In­dian coastal re­gions are also af­fected by mi­croplas­tics. Hence Na­tional In­sti­tute of Oceanog­ra­phy has ini­ti­ated joint col­lab­o­ra­tive study with Japan and Nether­lands to bring out more in­for­ma­tion about plas­tic pol­lu­tion sta­tus in In­dian coastal zone.

Re­cently, the Union Min­istry of State for En­vi­ron­ment, For­est and Cli­mate Change re­vealed that 15,000 tonnes of plas­tic waste is gen­er­ated ev­ery day, out of which 9,000 tonnes is col­lected and pro­cessed, but 6,000 tonnes of plas­tic waste is not be­ing col­lected.

It is high time we un­der­stand that plas­tic, in­clud­ing biodegrad­able plas­tic, not only takes years to de­com­pose in our en­vi­ron­ment but rarely fully dis­ap­pears. No mat­ter how in­con­ve­nient the truth, it is im­por­tant that as cit­i­zens we take ac­tion and change our con­sump­tion pat­terns in favour of al­ter­na­tives to plas­tics so that we can min­imise our ex­po­sure to harm­ful ad­di­tives and also help our en­vi­ron­ment.

So the best thing we can do to pro­tect our wa­ter­ways is try to keep as much plas­tic as pos­si­ble out of the waste stream in the first place. For re­duc­ing the gen­er­a­tion of more plas­tics waste we have to take the 4 Rs pledge- Refuse, Re­duce, Re­use and Re­cy­cle.

1) Refuse dis­pos­able plas­tic when­ever and wher­ever pos­si­ble. 2) Re­duce our plas­tic foot­print. 3) Re­use durable, non- toxic straws, uten­sils, to- go con­tain­ers, bot­tles, bags, and other ev­ery­day items. And fi­nally 4) Re­cy­cle what we can’t refuse, re­duce or re­use.

No one knows how much de­bris makes up the Great Pa­cific Garbage Patch. The North Pa­cific Sub­trop­i­cal Gyre is too large for sci­en­tists to trawl.

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