Umba weHlabathi
Izingcolisi eziphilayo eziqhubekayo (POPs) ziikhemikhali eziyityhefu ezichaphazela kakubi impilo yabantu kunye nokusingqongileyo kwihlabathi jikelele. Ngenxa yokuba zinokuthuthwa ngomoya nangamanzi, uninzi lweePOPs eziveliswa kwilizwe elinye zinokuchaphazela abantu nezilwanyana zasendle ezikude nendawo ezisetyenziswayo nezikhululwa kuzo. Ziyaqhubeka ixesha elide kwimo engqongileyo kwaye ziyakwazi ukuqokelela kwaye zidlule ukusuka kolunye uhlobo ukuya kwesinye ngekhonkco lokutya. Ukujongana nale nkxalabo yehlabathi, iUnited States yadibanisa imikhosi kunye namanye amazwe angama-90 kunye noLuntu lwaseYurophu ukuba lusayine isivumelwano seZizwe eziManyeneyo eStockholm, eSweden, ngoMeyi 2001. Ngaphantsi komnqophiso, owaziwa ngokuba yiNgqungquthela yaseStockholm, amazwe avumile ukunciphisa okanye ukuphelisa ukuveliswa, ukusebenzisa, kunye / okanye ukukhululwa kwe-POPs eziphambili ze-12 (jonga ibhokisi), kwaye icaciswe phantsi kweNgqungquthela i-POP yenkqubo yokuhlaziywa kwesayensi yomhlaba wonke.
Uninzi lweePOP ezibandakanyiweyo kwiNgqungquthela yaseStockholm azisaveliswa kweli lizwe. Nangona kunjalo, abemi base-US kunye neendawo zokuhlala zisenokuba semngciphekweni we-POPs eziye zazingisa kwindalo evela kwii-POP eziveliswe ngempazamo ezikhutshwe e-United States, ukusuka kwii-POP ezikhutshwa kwenye indawo kwaye zihanjiswe apha (ngomoya okanye ngamanzi, umzekelo), okanye zombini. Nangona amazwe amaninzi ahambele phambili kwezoqoqosho aye athabatha inyathelo elingqongqo lokulawula iiPOPs, amazwe amaninzi asakhasayo asandul’ ukuqalisa nje ngokufanelekileyo ukuthintela imveliso, ukusetyenziswa nokukhululwa kwawo.
INgqungquthela yaseStockholm yongeza inkalo ebalulekileyo yehlabathi kwiinzame zethu zesizwe nezengingqi zokulawula iiPOPs. Nangona i-United States ingekabinalo iQela kwiNgqungquthela yaseStockholm, iNgqungquthela idlale indima ebonakalayo kulawulo lweekhemikhali eziyingozi kwinqanaba lesizwe nelehlabathi. Umzekelo, i-EPA kunye namazwe anciphise kakhulu ukukhutshwa kwee-dioxins kunye neefuran emhlabeni, emoyeni, nakumanzi avela kwimithombo yase-US. Ukongeza ekuhloleni ii-dioxins, i-EPA ikwasebenza ngenkuthalo ekunciphiseni i-DDT kwimithombo yehlabathi. I-United States kunye neKhanada batyikitye isivumelwano sokupheliswa kwe-Virtual ye-Toxic Substances kwi-Great Lakes ukunciphisa ukukhutshwa kwezinto eziyityhefu. I-United States ikwatyikitye i-protocol yengingqi yeKomishoni yezoQoqosho yeZizwe eziManyeneyo yaseYurophu kwiiPOPs phantsi kweNgqungquthela yoNgcoliseko loMoya oluLunde oluNqamshelwa kwiMida ejongene neStockholm Convention POPs kunye neminye imichiza.
Ukongeza kwizivumelwano ezinxulumene nee-POPs i-United States ithathe inxaxheba ekutyikityeni, i-United States ikwabonelele ngenkxaso yemali neyobugcisa eyaneleyo kumazwe kwihlabathi jikelele exhasa ukuncitshiswa kwe-POPs. Ambalwa kula manyathelo abandakanya i-dioxin kunye ne-furan yokukhutshwa kwempahla e-Asia naseRashiya, kunye nokunciphisa imithombo ye-PCB eRashiya.
Yintoni iiPOPs?
Uninzi lwee-POPs zazisetyenziswa kakhulu ngexesha le-boom kwimveliso yemizi-mveliso emva kweMfazwe Yehlabathi II, xa amawaka eekhemikhali zokwenziwa zaziswa ekusetyenzisweni kwezorhwebo. Uninzi lwale michiza lwangqineka luluncedo ekulawuleni izinambuzane ezitshabalalisayo nezifo, imveliso yezityalo namashishini. Kwale michiza inye, nangona kunjalo, ibe nemiphumo ebingalindelekanga kwimpilo yabantu nakwimekobume.
Abantu abaninzi baqhelene nezinye zePOPs zaziwayo, ezifana neePCB, DDT, kunye needioxins. IiPOPs ziquka uluhlu lwezinto eziquka:
Iikhemikhali eziveliswe ngabom ngoku okanye ezikhe zasetyenziswa kwezolimo, ukulawula izifo, ukwenziwa kwezinto, okanye iinkqubo zoshishino. Imizekelo ibandakanya ii-PCB, eziye zaba luncedo kwiintlobo ngeentlobo zezicelo zemizi-mveliso (umzekelo, kwiziguquli zombane kunye neecapacitor ezinkulu, njengehydraulic kunye nolwelo lokutshintshiselana ngobushushu, nanjengezongezo kwiipeyinti nakwizithambiso) kunye neDDT, esasetyenziselwa ukulawula iingcongconi ezithwala isifo seengcongconi kwezinye iindawo zehlabathi.
Iikhemikhali eziveliswe ngempazamo, ezinjengee-dioxins, eziphuma kwezinye iinkqubo zemizi-mveliso kunye nokutsha (umzekelo, ukutshiswa kwenkunkuma kamasipala nezonyango kunye nokutshiswa kwenkunkuma ngasemva kwendlu).
Ingxaki yeDDT
I-DDT kusenokwenzeka ukuba sesinye sezona zibulali-zinambuzane zidumileyo neziphikiswayo kwezakha zenziwa. Kuqikelelwa ukuba i-4 yeebhiliyoni zeeponti zale michiza engabizi kwaye esebenzayo ngokwembali iye yaveliswa kwaye yasetyenziswa emhlabeni wonke ukususela ngo-1940. E-United States, i-DDT yayisetyenziswa kakhulu kwizityalo zezolimo, ngokukodwa umqhaphu, ukusuka kwi-1945 ukuya ku-1972. I-DDT yayisetyenziselwa ukukhusela amajoni kwizifo ezithwala izinambuzane ezifana ne-malaria kunye ne-typhus kwisixhobo esibalulekileyo se-World War II. Ukusetyenziswa kakhulu kwale khemikhali ezingisa kakhulu, nangona kunjalo, kukhokelele ekungcolisekeni kwendalo kunye nokuqokelelwa kwe-DDT ebantwini nakwizilwanyana zasendle - into eyaziswa eluntwini nguRachel Carson kwincwadi yakhe ka-1962 ethi Silent Spring. Ubutyebi belabhorathri yenzululwazi kunye nedatha yasendle ngoku sele iqinisekisile uphando olusuka kwiminyaka yoo-1960 olucebise, phakathi kwezinye iziphumo, ukuba amanqanaba aphezulu e-DDE (i-metabolite ye-DDT) kwiintaka ezithile ezidliwayo abangela ukuba amaqokobhe amaqanda azo abe bhityile kakhulu kangangokuba angakwazi ukuvelisa inzala ephilayo.
Olunye uhlobo lweentaka olunovelwano ngokukhethekileyo kwiDDE yayilukhozi olunempandla. Inkxalabo yoluntu malunga nokwehla kwamaxhalanga kunye nokuba nokwenzeka kwezinye iziphumo ezinobungozi zexesha elide zokuvezwa kweDDT ebantwini nakwizilwanyana zasendle kwabangela ukuba i-Arhente yoKhuseleko lokuSingqongileyo (EPA) ikurhoxise ukubhaliswa kweDDT ngo-1972.
Abahambi abanqumla imida
Uthuli Lwehlabathi Lonke: Lo mzobo ubonisa umfanekiso wesathelayithi wokudlula kwelifu lothuli ukunqumla uLwandlekazi lwePasifiki ukuya kuMntla Melika. Eli lifu lothuli laphakanyiswa sisiphango saseAsia ngoAprili 2001. Kwakhona kuboniswa ilifu lothuli elisuka kumntla weAfrika lisingise entshona phezu koLwandlekazi lweAtlantiki.
Olona khuthazo olukhulu lweNgqungquthela yaseStockholm yayikukufunyaniswa kongcoliseko lwePOPs kwimimandla ecocekileyo yeArctic – amawaka eemayile ukusuka kuwo nawuphi na umthombo owaziwayo. Ubungqina obuninzi bothutho olude lwegesi ephuma emoyeni kunye ne-particle ukuya e-United States igxile kuthuli okanye umsi kuba zibonakala kwimifanekiso yesathelayithi. Ukulandela intshukumo yee-POP ezininzi kwimo engqongileyo kuntsokothile kuba ezi khompawundi zinokubakho kwizigaba ezahlukeneyo (umzekelo, njengerhasi okanye zincanyathiselwe kumasuntswana omoya) kwaye zinokutshintshwa phakathi kwemidiya yokusingqongileyo. Umzekelo, ezinye ii-POPs zinokuthwalwa iimayile ezininzi xa ziphuma umphunga emanzini okanye kumphezulu womhlaba ukuya emoyeni, okanye xa zibhengeza kumasuntswana asemoyeni. Emva koko, banokubuyela eMhlabeni ngamasuntswana okanye kwikhephu, emvuleni, okanye kwinkungu. IiPOP zikwahamba nolwandle, imilambo, amachibi, kwaye, kancinci, ngoncedo lwezilwanyana ezithwala izilwanyana, njengeentlobo ezifudukayo.
Zeziphi iintshukumo zaseKhaya ezithathiweyo ukulawula iiPOPs?
I-United States ithathe amanyathelo aqinileyo asekhaya ukunciphisa ukukhutshwa kwee-POPs. Umzekelo, akukho nasinye sezibulali-zinambuzane zePOPs zoqobo ezidweliswe kwiNgqungquthela yaseStockholm ebhalisiweyo ukuba ithengiswe kwaye isasazwe eUnited States namhlanje kwaye ngo-1978, iCongress yakuthintela ukwenziwa kweePCBs kwaye yathintela kabukhali ukusetyenziswa kwezitokhwe eziseleyo zePCB. Ukongeza, ukusukela ngo-1987, i-EPA kunye namazwe baye banciphisa ngokufanelekileyo ukukhutshwa kokusingqongileyo kwee-dioxins kunye neefuran emhlabeni, emoyeni, nakumanzi avela kwimithombo yase-US. Ezi zenzo zolawulo, kunye neenzame zokuzithandela zoshishino lwase-US, zibangele ukuhla okukhulu kweepesenti ezingama-85 kukukhutshwa kwe-dioxin kunye ne-furan emva ko-1987 kwimithombo eyaziwayo yemizi-mveliso. Ukuqonda ngcono iingozi ezinxulumene nokukhutshwa kwe-dioxin, i-EPA ibisenza uphononongo olubanzi lwesayensi ye-dioxin kwaye iya kuvavanya izenzo ezongezelelweyo ezinokukhusela ngakumbi impilo yabantu kunye nokusingqongileyo.
Ukuyekisa ukusetyenziswa kweDDT
Ukutyhubela iminyaka, iUnited States ithathe amanyathelo amaninzi okuthintela ukusetyenziswa kweDDT:
Ngowe-1969: Emva kokufundisisa ngokuzingisa kweentsalela zeDDT kwimekobume, iSebe Lezolimo laseUnited States (USDA) liyakurhoxisa ukubhaliswa kokusetyenziswa kweDDT (kwimithi enethunzi, kwicuba, ekhaya nakwiindawo ezihlala emanzini).
Ngowe-1970: IUSDA yazirhoxisa izicelo zeDDT kwizityalo, kwizityalo zorhwebo nakwimveliso yeeplanga, kwanangeenjongo zokwakha.
1972: Phantsi kwegunya le-EPA, ukubhaliswa kweemveliso eziseleyo zeDDT kuyarhoxiswa.
Ngo-1989: Ukusetyenziswa okushiyekileyo (ukusetyenziswa kwezempilo yoluntu ekulawuleni izifo ezithwalwa zizilwanyana, ukusetyenziswa emkhosini ukuze kuvalelwe umntu yedwa, kunye nokusetyenziswa kweziyobisi ezimiselwe ngugqirha ukulawula iintwala zomzimba) kuyekwa ngokuzithandela.
Namhlanje: Akukho kubhaliswa kwe-DDT yase-US, okuthetha ukuba ayinakuthengiswa ngokusemthethweni okanye isasazwe eUnited States.
Ukulawula iiDioxins
I-EPA ilandele ulawulo nolawulo lweedioxins kunye neefuran ezikhutshwa emoyeni, emanzini, nasemhlabeni. UMthetho woMoya ococekileyo ufuna ukusetyenziswa kobuchwephesha obufikelelekayo bokulawula ukungcola komoya okunobungozi, kuquka i-dioxins kunye ne-furans. Imithombo emikhulu elawulwa phantsi kweli gunya ibandakanya ukutshiswa kwenkunkuma kamasipala, yonyango, kunye neyingozi; ukwenziwa kwe-pulp kunye nephepha; kunye neenkqubo ezithile zokuveliswa kwesinyithi kunye nokucokisa. Ukukhutshwa kwe-Dioxin emanzini kulawulwa ngokudityaniswa kwezixhobo ezisekelwe kumngcipheko kunye neteknoloji esekwe phantsi koMthetho waManzi acocekileyo. Ukucocwa komhlaba ongcoliswe yidioxin yinxalenye ebalulekileyo ye-EPA Superfund kunye neenkqubo zokuLungisa uMthetho woLondolozo lweZibonelelo kunye noMthetho wokuBuyisa. Izenzo zokuzithandela zokulawula i-dioxins kunye ne-furan ziquka i-EPA's Persistent, Bioaccumulative, kunye neNkqubo ye-Toxics kunye ne-Dioxin Exposure Initiative, zombini eziqokelela ulwazi ukwazisa ngezenzo zexesha elizayo kunye nokunciphisa ngakumbi ingozi ehambelana nokuvezwa kwe-dioxin.
Ngaba ii-POPs zibachaphazela njani abantu kunye nezilwanyana zasendle?
Uphononongo lunxulumanise ukuvezwa kwee-POPs nokuncipha, izifo, okanye ukungaqhelekanga kwinani leentlobo zezilwanyana zasendle, kuquka iintlobo ezithile zeentlanzi, iintaka, kunye nezilwanyana ezanyisayo. Izilwanyana zasendle nazo zinokusebenza njengabalindi kwimpilo yabantu: izinto ezingaqhelekanga okanye ukwehla okufunyaniswe kubuninzi bezilwanyana zasendle kunokuvakala intsimbi yokulumkisa kwangoko ebantwini. Ukungahambi kakuhle kokuziphatha kunye neziphene zokuzalwa kwiintlanzi, iintaka, kunye nezilwanyana ezincancisayo kunye nakwiindawo ezijikeleze i-Great Lakes, umzekelo, kukhokelele izazinzulu ukuba ziphande ukuvezwa kwee-POPs kuluntu lwabantu (jonga ngezantsi ngolwazi oluthe kratya malunga namachibi amakhulu).
Kubantu, ukuzala, uphuhliso, ukuziphatha, i-neurologic, i-endocrine, kunye nemiphumo emibi ye-immunologic zempilo ziye zadibaniswa nee-POPs. Abantu bachanabeka ikakhulu kwii-POPs ngokutya okungcolisekileyo. Iindlela ezincinci zokuvezwa zibandakanya ukusela amanzi angcolileyo kunye nokunxibelelana ngqo neekhemikhali. Ebantwini nakwezinye izilwanyana ezanyisayo ngokufanayo, ii-POPs zinokugqithiselwa nge-placenta kunye nobisi lwebele ukuya kwinzala ekhulayo. Noko ke, kufanele kuphawulwe ukuba phezu kwako nje oku kubhenceka okunokubakho, iingenelo ezaziwayo zokuncancisa ziyodlula lee iingozi ezirhanelwayo.
Inani labemi basemngciphekweni othile wokuvezwa kwee-POPs, kubandakanywa abantu abakutya kwabo kubandakanya izixa ezikhulu zentlanzi, i-shellfish, okanye ukutya kwasendle okunamafutha aphezulu kwaye afunyenwe ekuhlaleni. Umzekelo, abantu bomthonyama banokuba semngciphekweni ngakumbi kuba beqwalasela izithethe zenkcubeko nezomoya ezinxulumene nokutya kwabo. Kubo, ukuloba kunye nokuzingela akusiyo imidlalo okanye ukuzonwabisa, kodwa kuyingxenye yendlela yokuphila yendabuko, apho kungekho nxalenye eluncedo yokubambisa ichithwa. Kwiindawo ezikude zaseAlaska nakwezinye iindawo, ukutya okufunyenwe ekuhlaleni kusenokuba yeyona ndlela ifumanekayo yesondlo (jonga ngezantsi ukuze ufumane ulwazi oluthe kratya kwiArctic).
Ukongeza, abantu abanovakalelo, abanjengabantwana, abantu abadala, kunye nabo banenkqubo yomzimba yokuzikhusela ecinezelekileyo, bahlala bechanabeke ngakumbi kwiintlobo ezininzi zongcoliso, kubandakanya iiPOPs. Ngenxa yokuba ii-POPs ziye zanxulunyaniswa nokukhubazeka kwenzala, amadoda nabafazi abakwiminyaka yokuzala abantwana nabo banokuba semngciphekweni.
I-POPS kunye nekhonkco lokutya
Ii-POPs zisebenza ngendlela yazo kwikhonkco lokutya ngokuqokelela kumafutha omzimba wezinto eziphilayo kwaye zigxile ngakumbi njengoko zihamba ukusuka kwesinye isidalwa ukuya kwesinye. Le nkqubo yaziwa ngokuba yi "biomagnification." Xa ungcoliseko lufunyenwe kwixabiso elincinci ezantsi kwekhonkco lokutya lwe-biomagnify, lunokubangela ingozi enkulu kumarhamncwa ezondla phezulu kwikhonkco lokutya. Oku kuthetha ukuba nokukhutshwa okuncinci kwee-POP kunokuba neempembelelo ezibalulekileyo.
I-Biomagnification in Action: Uphononongo luka-1997 olwenziwa yi-Arctic Monitoring and Assessment Programme, ebizwa ngokuba yi-Arctic Pollution Issues: A State of the Arctic Environment Report, yafumanisa ukuba i-caribou kwi-Canada's Northwest Territories yayinomlinganiselo ophindwe ka-10 wamanqanaba e-PCB njengelembu ezitya kuwo; Amanqanaba ePCB kwiingcuka ezazisitya kwicaribou aye anda ngokuphindwe kangangama-60 kunobulembu.
Indima Yenzululwazi
Nangona izazinzulu zinokuninzi ekufuneka zifunde malunga neekhemikhali ze-POPs, amashumi eminyaka ophando lwezenzululwazi lwandise kakhulu ulwazi lwethu ngeempembelelo zePOPs ebantwini nakwizilwanyana zasendle. Umzekelo, uphononongo lwaselabhoratri lubonise ukuba iidosi eziphantsi zee-POP ezithile zichaphazela kakubi iinkqubo zamalungu kunye nemiba yophuhliso. Uphononongo lukwabonise ukuba ukuchanabeka okungapheliyo kwiidosi eziphantsi zee-POP ezithile kunokubangela inzala kunye nentsilelo yenkqubo yomzimba yokuzikhusela. Ukuvezwa kumanqanaba aphezulu eekhemikhali ezithile zePOPs - ngaphezulu kunesiqhelo esifunyanwa ngabantu kunye nezilwanyana zasendle - kunokubangela umonakalo omkhulu okanye ukufa. Izifundo ze-epidemiological zabantu abavezwayo kunye nezifundo zezilwanyana zasendle zinokubonelela ngolwazi olungakumbi malunga neempembelelo zempilo. Nangona kunjalo, ngenxa yokuba amaphononongo anjalo alawulwa ngaphantsi kunezifundo zebhubhoratri, ezinye iingcinezelo azikwazi ukukhutshelwa ngaphandle njengesizathu semiphumo emibi.
Njengoko siqhubeka nokufunda ii-POPs, siza kufunda banzi malunga nomngcipheko wokuvezwa kwee-POP kuluntu ngokubanzi, ukuba zininzi kangakanani iintlobo zezinto eziphilayo (kubandakanywa nabantu) ezivezwayo, kwaye zeziphi iziphumo ezinayo ii-POP kwezi ntlobo kunye ne-ecosystem yazo. I-EPA iphuhlise ingxelo eshwankathela inzululwazi kwiiPOPs (jonga iZibonelelo ezingezantsi).
Oovimba beePOPs
Ii-POPs zinokudipozithwa kwi-ikhosistim yaselwandle namanzi acwengileyo ngokukhutshwa kwamanzi amdaka, ukubekwa kwe-atmospheric, ukubaleka, kunye nezinye iindlela. Ngenxa yokuba ii-POPs zinokunyibilika okuphantsi kwamanzi, zibopha ngamandla kwi-particle ye-substance kwintlenga yasemanzini. Ngenxa yoko, intlenga inokusebenza njengemithombo yamanzi okanye “iintsinki” zeePOPs. Xa zicandelwe kwezi sediments, iiPOPs zinokukhutshwa ekujikelezweni ixesha elide. Ukuba ziphazanyiwe, nangona kunjalo, zinokuphinda zibuyiselwe kwi-ecosystem kunye nekhonkco lokutya, ezinokuthi zibe ngumthombo wongcoliseko lwasekhaya, kunye nehlabathi jikelele.
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