Inkinga Yomhlaba Wonke
Izinto ezingcolisa izinto eziphilayo eziqhubekayo (POPs) zingamakhemikhali anobuthi athinta kabi impilo yabantu kanye nemvelo emhlabeni jikelele. Ngenxa yokuthi angakwazi ukuthuthwa ngomoya namanzi, ama-POP amaningi akhiqizwa ezweni elilodwa angakwazi futhi athinte abantu nezilwane zasendle kude nalapho asetshenziswa futhi adedelwa khona. Ziphikelela isikhathi eside endaweni ezungezile futhi zinganqwabelana futhi zidlule zisuka kolunye uhlobo ziye kolunye ngochungechunge lokudla. Ukuze kubhekwane nalokhu kukhathazeka komhlaba wonke, i-United States yahlanganyela namanye amazwe angu-90 kanye Nomphakathi WaseYurophu ukuze isayine isivumelwano esiyisisekelo seNhlangano Yezizwe Ezihlangene e-Stockholm, eSweden, ngoMeyi 2001. Ngaphansi kwesivumelwano, esaziwa ngokuthi i-Stockholm Convention, amazwe avumelana ukunciphisa noma ukuqeda ukukhiqizwa, ukusetshenziswa, kanye/noma ukukhululwa kwe-POP eyinhloko engu-12 (bheka ibhokisi), futhi kwacaciswa ngaphansi kweSivumelwano ngenqubo yesayensi yokubuyekeza amakhemikhali e-P .
Ama-POP amaningi afakwe ku-Stockholm Convention awasakhiqizwa kuleli zwe. Kodwa-ke, izakhamizi zase-US nezindawo zokuhlala zisengaba sengcupheni yama-POP aphikelele emvelweni kusukela kuma-POP akhiqizwe ngokungenhloso akhululwa e-United States, kuma-POP akhululwa kwenye indawo abese ethuthwa lapha (ngomoya noma ngamanzi, isibonelo), noma asuka kokubili. Nakuba amazwe amaningi athuthukile ethathe isinyathelo esiqinile sokulawula ama-POP, amazwe amaningi asathuthuka asanda kuqala ukukhawulela ukukhiqizwa kwawo, ukusetshenziswa kwawo, nokukhululwa kwawo.
I-Stockholm Convention yengeza isici esibalulekile somhlaba wonke emizamweni yethu kazwelonke neyesifunda yokulawula ama-POP. Nakuba i-United States ingakabi Ingxenye Yengqungquthela yase-Stockholm, I-Convention idlale indima ebalulekile ekulawuleni amakhemikhali ayingozi kokubili ezingeni likazwelonke nelomhlaba. Isibonelo, i-EPA kanye nezifunda zinciphise kakhulu ukukhishwa kwama-dioxin nama-furan emhlabeni, emoyeni, namanzi avela emithonjeni yase-US. Ngaphezu kokuhlola ama-dioxin, i-EPA iphinde yasebenza ngokuzikhandla ekwehliseni i-DDT emithonjeni yomhlaba. I-United States ne-Canada basayine isivumelwano Sokuqedwa Okubonakalayo Kwezinto Ezinobuthi Eziqhubekayo e-Great Lakes ukuze kuncishiswe ukukhishwa kwezinto ezinobuthi. I-United States iphinde yasayina iphrothokholi yesifunda yeKhomishana Yezomnotho Yezizwe Ezihlangene YaseYurophu mayelana nama-POP ngaphansi kweSivumelwano Sokungcoliswa Komoya Okudlula Ibanga elide esikhuluma neStockholm Convention POPs namanye amakhemikhali.
Ukwengeza ezivumelwaneni ezihlobene nama-POP i-United States ebambe iqhaza ekusayineni, i-United States iphinde yahlinzeka ngosekelo olwanele lwezezimali nolwezobuchwepheshe emazweni emhlabeni wonke asekela ukuncishiswa kwama-POP. Ezimbalwa zalezi zinhlelo zifaka phakathi i-dioxin ne-furan yokukhishwa kwempahla e-Asia nase-Russia, kanye nokwehliswa kwemithombo ye-PCB e-Russia.
Ayini ama-POP?
Ama-POP amaningi asetshenziswa kakhulu ngesikhathi sokukhula kokukhiqizwa kwezimboni ngemva kweMpi Yezwe II, lapho izinkulungwane zamakhemikhali okwenziwa zisetshenziswa ukuze zisetshenziswe. Amaningi ala makhemikhali aba usizo ekulawuleni izinambuzane nezifo, ekukhiqizeni izitshalo, nasezimbonini. Lawa makhemikhali afanayo, nokho, abe nemiphumela engalindelekile empilweni yomuntu nasendaweni ezungezile.
Abantu abaningi bajwayelene namanye ama-POP aziwa kakhulu, njengama-PCB, i-DDT, nama-dioxin. Ama-POP afaka uhla lwezinto ezihlanganisa:
Amakhemikhali akhiqizwa ngamabomu njengamanje noma ake asetshenziswa kwezolimo, ukulawula izifo, ukukhiqiza, noma izinqubo zezimboni. Izibonelo zifaka ama-PCB, abe lusizo ezinhlelweni ezihlukene zezimboni (isb., kuma-transformer kagesi nama-capacitor amakhulu, njengama-hydraulic kanye noketshezi lokushintshanisa ukushisa, nanjengezithasiselo kupende nezinto zokugcoba) kanye ne-DDT, esasetshenziswa namanje ukulawula omiyane abathwala umalaleveva kwezinye izingxenye zomhlaba.
Amakhemikhali akhiqizwa ngokungenhloso, njengama-dioxin, avela kwezinye izinqubo zezimboni kanye nokusha (isibonelo, ukushiswa kukamasipala nemfucuza yezokwelapha kanye nokushiswa kukadoti egcekeni).
Inkinga ye-DDT
I-DDT cishe ingesinye sezibulala-zinambuzane ezidume kakhulu neziyimpikiswano ezake zenziwa. Kulinganiselwa ukuthi amaphawundi ayizigidi eziyizinkulungwane ezingu-4 aleli khemikhali elingabizi futhi eliphumelelayo ngokomlando liye lakhiqizwa futhi lasetshenziswa emhlabeni wonke kusukela ngo-1940. E-United States, i-DDT yasetshenziswa kakhulu ezitshalweni zezolimo, ikakhulukazi ukotini, kusukela ngo-1945 kuya ku-1972. I-DDT yaphinde yasetshenziselwa ukuvikela amasosha ezifweni ezithwalwa izinambuzane ezifana nomalaleveva kanye ne-typhus ezingxenyeni ezibalulekile zezempilo phakathi neMpi Yezwe II. Ukusetshenziswa kanzima kwaleli khemikhali elibeleselayo, nokho, kwaholela ekungcolisweni kwemvelo okusabalele kanye nokunqwabelana kwe-DDT kubantu nasezilwaneni zasendle - into eyaziswa umphakathi nguRachel Carson encwadini yakhe yango-1962, ethi Silent Spring. Ingcebo yelabhorethri yesayensi kanye nedatha yasensimini manje isiqinisekise ucwaningo lwango-1960 olwaphakamisa, phakathi kweminye imiphumela, ukuthi amazinga aphezulu e-DDE (i-metabolite ye-DDT) ezinyonini ezithile ezidla inyama abangela ukuba amagobolondo amaqanda azo azace ngendlela emangalisayo kangangokuthi angakwazi ukukhiqiza inzalo ephilayo.
Olunye uhlobo lwezinyoni oluzwela kakhulu i-DDE kwakuwukhozi olunempandla. Ukukhathazeka komphakathi mayelana nokwehla kwezinkozi kanye nokuba nokwenzeka kweminye imiphumela eyingozi yesikhathi eside yokuchayeka kwe-DDT kubantu nasezilwaneni zasendle kwashukumisela i-Environmental Protection Agency (EPA) ukuba ikhansele ukubhaliswa kwe-DDT ngo-1972.
Abahambi Abahamba Ngaphakathi
I-Global Dust: Lesi sibalo sibonisa isithombe sesathelayithi sokudlula kwefu lothuli ku-Pacific Ocean kuya eNyakatho Melika. Lelifu lothuli laphakanyiswa isiphepho e-Asia ngo-April 2001. Kuphinde kuboniswe ifu lothuli elivela enyakatho ye-Afrika elihamba entshonalanga phezu koLwandlekazi i-Atlantic.
Umfutho omkhulu weNgqungquthela yaseStockholm kwaba ukutholakala kokungcoliswa kwama-POP ezindaweni ezihlanzekile ze-Arctic - izinkulungwane zamamayela ukusuka kunoma yimuphi umthombo owaziwayo. Ubufakazi obuningi bokuthuthwa kwebanga elide legesi ephuma emoyeni kanye nezinto eziyizinhlayiya ukuya e-United States bugxile othulini noma entuthuni ngoba zibonakala ezithombeni zesathelayithi. Ukulandelela ukunyakaza kwama-POP amaningi endaweni kuyinkimbinkimbi ngoba lezi zinhlanganisela zingaba khona ngezigaba ezahlukene (isb, njengegesi noma zixhunywe ezinhlayiyeni ezihamba emoyeni) futhi zingashintshaniswa phakathi kwemithombo yezemvelo. Isibonelo, amanye ama-POP angathwalwa amamayela amaningi uma ehwamuka emanzini noma ezindaweni ezisemhlabeni aye emoyeni, noma lapho ekhangisa ezinhlayiyeni ezihamba emoyeni. Ngemva kwalokho, bangabuyela eMhlabeni ngezinhlayiya noma eqhweni, emvuleni, noma enkungwini. Ama-POP aphinde adlule olwandle, emifuleni, emachibini, futhi, ngokwezinga elincane, ngosizo lwezilwane ezithwala izilwane, njengezinhlobo ezifudukayo.
Yiziphi Izenzo Zasekhaya Ezithathiwe Ukulawula Ama-POP?
I-United States ithathe isinyathelo esiqinile sasekhaya sokunciphisa ukukhishwa kwe-POP. Isibonelo, azikho izibulala-zinambuzane zangempela ze-POP ezisohlwini lwe-Stockholm Convention ezibhaliselwe ukudayiswa nokusatshalaliswa e-United States namuhla futhi ngo-1978, iCongress yakwenqabela ukwakhiwa kwama-PCB futhi yakhawulela kakhulu ukusetshenziswa kwezitoko ze-PCB ezisele. Ngaphezu kwalokho, kusukela ngo-1987, i-EPA kanye nezifunda ziye zanciphisa ngempumelelo ukukhishwa kwemvelo kwama-dioxin nama-furan emhlabeni, emoyeni, namanzi avela emithonjeni yase-US. Lezi zenzo zokulawula, kanye nemizamo yokuzithandela yemboni yase-US, kubangele ukwehla okukhulu kwamaphesenti angama-85 engqikithini yokukhishwa kwe-dioxin ne-furan ngemva kuka-1987 emithonjeni yezimboni eyaziwayo. Ukuze uqonde kangcono ubungozi obuhlobene nokukhishwa kwe-dioxin, i-EPA ibilokhu yenza ukuhlola kabusha okuphelele kwesayensi ye-dioxin futhi izobe ihlola izenzo ezengeziwe ezingase zivikele nakakhulu impilo yabantu kanye nemvelo.
Ukumisa ukusetshenziswa kwe-DDT
Eminyakeni edlule, i-United States ithathe izinyathelo ezimbalwa zokukhawulela ukusetshenziswa kwe-DDT:
1969: Ngemva kokuhlola ukuphikelela kwezinsalela ze-DDT endaweni ezungezile, uMnyango Wezolimo wase-United States (USDA) ukhansela ukubhaliswa kokusetshenziswa okuthile kwe-DDT (ezihlahleni ezinomthunzi, kugwayi, ekhaya, nasezindaweni ezihlala emanzini).
1970: I-USDA ikhansela izicelo ze-DDT ezitshalweni, ezitshalweni zezentengiselwano, nemikhiqizo yezinkuni, kanye nezinjongo zokwakha.
1972: Ngaphansi kwegunya le-EPA, ukubhaliswa kwemikhiqizo esele ye-DDT kuyakhanselwa.
1989: Ukusetshenziswa okusele okukhishiwe (ukusetshenziswa kwezempilo komphakathi ukulawula izifo ezithwalwa yizilwane, ukusetshenziswa kwezempi ukuze uvalelwe yedwa, kanye nokusetshenziswa kwemithi kadokotela ukuze ulawule izintwala zomzimba) kuyekwa ngokuzithandela.
Namuhla: Akukho ukubhaliswa kwase-US kwe-DDT, okusho ukuthi ngeke ngokusemthethweni ithengiswe noma isatshalaliswe e-United States.
Ukulawula ama-Dioxin
I-EPA iphishekele ukulawula nokuphathwa kwama-dioxin nama-furan akhishelwa emoyeni, emanzini nasenhlabathini. I-Clean Air Act idinga ukusetshenziswa kobuchwepheshe obufinyelelekayo bokulawula izinto ezingcolisa umoya eziyingozi, okuhlanganisa ama-dioxin nama-furan. Imithombo emikhulu elawulwa ngaphansi kwalesi siphathimandla ihlanganisa ukushiswa kwemfucuza kamasipala, yezokwelapha, kanye neyingozi; ukukhiqizwa kwe-pulp namaphepha; kanye nezinqubo ezithile zokukhiqiza nokucwengisiswa kwezinsimbi. Ukukhishwa kwe-Dioxin emanzini kulawulwa ngenhlanganisela yamathuluzi asekelwe engozini kanye nasekelwe kubuchwepheshe asungulwe ngaphansi koMthetho Wamanzi Ahlanzekile. Ukuhlanzwa komhlaba ongcoliswe yi-dioxin kuyingxenye ebalulekile ye-EPA Superfund kanye nezinhlelo ze-Resource Conservation and Recovery Act Corrective Action. Izenzo zokuzithandela zokulawula ama-dioxin nama-furan zifaka i-EPA's Persistent, Bioaccumulative, and Toxics Programme kanye ne-Dioxin Exposure Initiative, zombili eziqoqa ulwazi ukuze zazise izenzo zesikhathi esizayo futhi zinciphise nakakhulu izingozi ezihlobene nokuchayeka kwe-dioxin.
Ama-POP Abathinta Kanjani Abantu Nezilwane Zasendle?
Ucwaningo luxhumanise ukuchayeka kwe-POP nokuncipha, izifo, noma okungavamile ezinhlobonhlobo zezilwane zasendle, okuhlanganisa izinhlobo ezithile zezinhlanzi, izinyoni, nezilwane ezincelisayo. Izilwane zasendle nazo zingasebenza njengabaqaphi bempilo yabantu: okungavamile noma ukwehla okutholwe ezilwaneni zasendle kungase kuzwakale insimbi yesixwayiso kubantu. Ukungajwayelekile kokuziphatha kanye nokukhubazeka kokuzalwa ezinhlanzini, ezinyonini nasezilwaneni ezincelisayo ngaphakathi nasezindaweni ezizungezile e-Great Lakes, isibonelo, kuholele ososayensi ukuthi baphenye ukuchayeka kwe-POP kubantu (bona ngezansi ukuze uthole ulwazi olwengeziwe ngamachibi Amakhulu).
Kubantu, ukuzala, ukuthuthuka, ukuziphatha, i-neurologic, i-endocrine, kanye nemiphumela emibi yezempilo ye-immunologic iye yaxhunyaniswa nama-POP. Abantu bachayeka kakhulu kuma-POP ngokudla okungcolile. Imizila yokuchayeka kancane ihlanganisa ukuphuza amanzi angcolile kanye nokuthintana ngqo namakhemikhali. Kubantu nakwezinye izilwane ezincelisayo ngokufanayo, ama-POP angadluliselwa nge-placenta nobisi lwebele aye enzalweni ekhulayo. Nokho, kufanele kuphawulwe ukuthi naphezu kwalokhu kuchayeka okungase kube khona, izinzuzo ezaziwayo zokuncelisa ibele zizidlula kude izingozi okusolekayo.
Inani labantu lisengcupheni ethile yokuchayeka kwe-POP, okuhlanganisa abantu ukudla kwabo okuhlanganisa nenani elikhulu lezinhlanzi, i-shellfish, noma ukudla kwasendle okunamafutha amaningi futhi okutholakala endaweni. Isibonelo, abantu bomdabu bangase babe sengozini ikakhulukazi ngenxa yokuthi bagcina amasiko nemikhuba yomoya ehlobene nokudla kwabo. Kubo, ukudoba nokuzingela akuwona umdlalo noma ukuzilibazisa, kodwa kuyingxenye yendlela yokuphila yendabuko, lapho kungekho ingxenye ewusizo yokubamba echithwayo. Ezindaweni ezikude zase-Alaska nakwezinye izindawo, ukudla okutholakala endaweni kungase kube ukuphela kwendlela etholakala kalula yokondleka (bheka ngezansi ukuze uthole ulwazi olwengeziwe nge-Arctic).
Ngaphezu kwalokho, abantu abazwelayo, njengezingane, abantu abadala, nalabo abanamasosha omzimba acindezelwe, ngokuvamile basengozini yokuthola izinhlobo eziningi zokungcola, okuhlanganisa nama-POP. Ngenxa yokuthi ama-POP axhunyaniswe nokukhubazeka kokuzala, abesilisa nabesifazane abaneminyaka yobudala yokuzala izingane nabo bangase babe sengozini.
I-POPS kanye ne-Food Chain
Ama-POP asebenza ngendlela yawo ochungechungeni lokudla ngokunqwabelana emafutheni omzimba wezinto eziphilayo futhi agxile kakhulu njengoba esuka kwesinye isidalwa aya kwesinye. Le nqubo yaziwa ngokuthi "i-biomagnification." Lapho ukungcola kutholakala ngamanani amancane ngaphansi kwe-biomagnify ye-food chain, kungadala ingozi enkulu ezilwaneni ezidla ezinye ezidla phezulu kweqoqo lokudla. Lokhu kusho ukuthi ngisho nokukhishwa okuncane kwama-POP kungaba nomthelela omkhulu.
I-Biomagnification in Action: Ucwaningo lwango-1997 olwenziwa yi-Arctic Monitoring and Assessment Programme, olubizwa nge-Arctic Pollution Issues: A State of the Arctic Environment Report, lwathola ukuthi i-caribou eseCanada's Northwest Territories yayinamazinga ama-PCB aphindwe izikhathi ezingu-10 kune-lichen eyayidla kuwo; Amazinga e-PCB ezimpisini ezazidla i-caribou akhuliswa cishe ngokuphindwe izikhathi ezingu-60 kunolwelwe.
Iqhaza Lesayensi
Nakuba ososayensi banokuningi okufanele bakufunde ngamakhemikhali e-POPs, amashumi eminyaka ocwaningo lwesayensi alukhulise kakhulu ulwazi lwethu ngemithelela ye-POP kubantu nasezilwaneni zasendle. Isibonelo, ucwaningo lwaselabhorethri lubonise ukuthi imithamo ephansi yama-POP athile ithinta kabi ezinye izinhlelo zezitho nezici zokuthuthuka. Ucwaningo luphinde lwabonisa ukuthi ukuchayeka okungamahlalakhona kumithamo ephansi yama-POP athile kungaholela entuleni yokuzala neyokuzivikela komzimba. Ukuchayeka emazingeni aphezulu amakhemikhali athile e-POP - aphezulu kunokujwayelekile okutholwa abantu nezilwane zasendle - kungabangela umonakalo omkhulu noma ukufa. Izifundo ze-Epidemiological zezibalo zabantu ezidaluliwe kanye nezifundo zezilwane zasendle zinganikeza ulwazi olwengeziwe ngemithelela yezempilo. Kodwa-ke, ngenxa yokuthi izifundo ezinjalo zilawulwa kancane kunezifundo zaselabhorethri, ezinye izingcindezi azikwazi ukukhishwa njengembangela yemiphumela emibi.
Njengoba siqhubeka nokufunda ama-POP, sizofunda kabanzi mayelana nengcuphe yokuchayeka kwe-POP emphakathini jikelele, ukuthi zingakanani izinhlobo zezilwane (okuhlanganisa abantu) ezivezwayo, nokuthi imiphi imithelela ama-POP anayo kulezi zinhlobo zezilwane kanye ne-ecosystem yazo. I-EPA yakha umbiko ofingqiwe isayensi kuma-POP (bona Izinsiza ngezansi).
Amachibi ama-POPs
Ama-POP angafakwa kuma-ecosystem asolwandle namanzi ahlanzekile ngokukhishwa kwamanzi angcolile, ukuchithwa komkhathi, ukugeleza, nezinye izindlela. Ngenxa yokuthi ama-POP anokuncibilika okuphansi kwamanzi, abopha ngokuqinile ezinhlayiyeni zenhlabathi yasemanzini. Ngenxa yalokho, ama-sediments angasebenza njengamanzi noma "amasinki" ama-POP. Uma ehlelwe kulezi zinsalela, ama-POP angakhishwa ukuze angahambi isikhathi eside. Uma ziphazamisekile, nokho, zingaphinda zifakwe ohlelweni lwezemvelo kanye nochungechunge lokudla, okungaba umthombo wokungcola kwendawo, ngisho nomhlaba wonke.
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