Ngaba i-PTFE ikhuselekile?

I-PTFE, eyaqanjwa sisigebenga semichiza yehlabathi iDuPont ngeminyaka yoo-1930s, yaba luphawu olulula lwekhitshi njengokusonga okuncamathelayo kunye neprosesa yokutya.

Kodwa i-PTFE inokufikelela esiphelweni esincangathi - kuba inkqubo yokuvelisa isebenzisa ikhemikhali enokubangela umhlaza, kwaye i-Arhente yoKhuseleko lweNdalo yase-US (EPA) ifuna ukuba ukusetyenziswa kwale khemikhali kuphele.

Ikhemikhali - ebizwa ngokuba yi-perfluorooctanoic acid, okanye i-PFOA - isetyenziselwa ukwenza iikhompawundi ezibizwa ngokuba yi-fluoropolymers, ezisetyenziselwa ukujika ukwenza i-polymer kunye nezinye iimveliso ezifana neoyile kunye neengubo zokugxotha amanzi kwikhaphethi, iingubo, isikhumba kunye nephepha.

Kuyaziwa ukuba i-PFOA ixhaphake kakhulu egazini loluntu ngokubanzi (nangona ikwindawo ephantsi), apho ihlala ukuya kuthi ga kwiminyaka eyi-10 ngaphambi kokuba isuswe.Kwizilwanyana zaselabhoratri, i-PFOA ibonisiwe ukuba ibangela umhlaza, umonakalo wesibindi, iziphene zokukhula, ukonakala kwamajoni omzimba kunye nokufa.Akukho bungqina buthe ngqo bokuba iyingozi ebantwini.

I-EPA yabuza iDuPont, kunye nezinye iinkampani ezisixhenxe ezisebenzisa i-PFOA kwiinkqubo zokuvelisa, ukuba ziyeke ukusetyenziswa kwayo.I-DuPont ivumile ukuthatha amanyathelo okuqinisekisa ukuba ngonyaka ka-2015, imichiza ayisayi kukhululwa kwindawo engqongileyo ukusuka kwimizi-mveliso yayo, nangona ingavumanga ukuyeka ukuyisebenzisa, okanye ukuyeka ukwenza ipholima.Ingxaki yeDupont kukuba, njengoko imi ngoku, ayikwazi ukwenza i-polymer ngaphandle kwale khemikhali, nangona isithi ijonge enye indawo.

Ewe, kukho izinto ezibonisa ukuba inkampani yaziwa kangangexesha elithile ukuba iPFOA iyingozi, kodwa yahlala iyisebenzisa.

Ngo-2004, iDuPont yahlawula i-US$300 yezigidi zeedola njengendawo yokuhlala ngaphandle kwenkundla kubahlali abangama-50,000 ababehlala kufutshane neplanti yaseWest Virginia kwaye bazisa isenzo seklasi ngokuchasene nenkampani, ibanga ukuba inoxanduva lokungcolisa amanzi asekhaya ngePFOA, ibangele. iziphene ekuzalweni kunye nezinye iingozi zempilo.Inkampani yazinza ngaphandle kokuvuma ityala.

Ukulandela oku, ngo-2005, i-EPA yahlawulisa i-DuPont i-16.5 yezigidi zeedola zaseMelika emva kokufumana inkampani yaziwa ngaphezu kweminyaka engamashumi amabini ukuba i-PFOA iyingozi, kwaye yathula ngayo.

Ngaba ndingayilahla ipani yam yokuqhotsa engaqhotswanga?

Xa kuziwa kwiimveliso ezingabambekiyo ngokwazo, uDuPont uthi akukho mngcipheko kubathengi.I-PFOA, ithi inkampani, isetyenziswa kwinkqubo yokuvelisa kodwa iyakhutshelwa ngaphandle ngexesha laloo nkqubo.Akukho PFOA eseleyo kwindawo engabambekiyo kwimveliso yokugqibela.

I-EPA iyavuma.'Ngeli xesha langoku, i-EPA ayikholelwa ukuba kukho nasiphi na isizathu sokuba abathengi bayeke ukusebenzisa nayiphi na abathengi okanye iimveliso ezinxulumene nezoshishino eziqulethe i-PFOA', ithi iwebhusayithi ye-EPA.

Nangona kunjalo, iipani zefry ezingabambekiyo zinokukhupha i-toxins.Kwiqondo lokushisa eliphezulu i-polymer iyaziwa ngokukhupha i-cocktail ye-15 iindidi ze-particle enetyhefu kunye neegesi, kuquka i-trifluoroacetic acid (TFA) kunye ne-phosgene.Le michiza iyaziwa njengetyhefu kwiintaka.Kwaye ebantwini kukho intloko ebuhlungu, ukubanda, umqolo obuhlungu, kunye nomkhuhlane – imeko eyaziwa ngokuba yi-'polymer flu'.

I-DuPont iyakuvuma oku, kodwa ithi ebantwini imeko iya kuguqulwa, kwaye nayiphi na imeko iyenzeka kuphela kumaqondo aphezulu, kungekhona ngexesha lokupheka okuqhelekileyo.

Kwanako oku bubulumko obamkelekileyo phakathi kwamaqela abathengi;eOstreliya, umzekelo, ngoNovemba ka-2004 'uvavanyo lwendlela' yeefrypans ezingezinti, uMbutho wabaThengi base-Australia wathi:

'Kuyinyani ukuba imichiza efana ne-trifluoroacetic acid (TFA) inokukhutshwa ngezinye izinto zokugquma kumaqondo obushushu aphezulu kakhulu.Kodwa akunakwenzeka ukuba yenzeke ngexesha lokupheka kwesiqhelo…Uphando alukhange lubonise iziphumo ezinobungozi zexesha elide ze-TFA ebantwini.Kweli nqanaba abukho ubungqina bokuba ukupheka ngokungakhuni kubangela umngcipheko wokhuseleko.'

Malunga neepesenti ezingama-80 zezixhobo zasekhitshini ezingabambekiyo ezithengiswayo e-Australia zisebenzisa i-polymer - ezinye zenziwe zezinye iinkampani zeekhemikhali zisebenzisa inkqubo efanayo ebandakanya i-PFOA.Akukho zityalo zokwenza iipolymer eOstreliya.

Kodwa iQela eliSebenzayo lokuSingqongileyo (EWG), iqela elizimeleyo labathengi base-US elingenzi nzuzo, liyaphikisana noku.Ithi i-polymer iqala ukuwohloka emva kokuba ubushushu be-cookware bufikelele malunga ne-260 ° C (500 ° F), kwaye iqala ukubola kakhulu ngaphezu kwe-350 ° C (660 ° F).Amafutha okupheka, i-oyile kunye nebhotolo ziya kuqala ukutshisa kunye nomsi malunga ne-200 ° C (392 ° F), kwaye inyama idla ngokuqhotyiswa phakathi kwe-200-230 ° C (400-450 ° F), kodwa iindawo ezishushu epanini ziyakwazi ngokulula. ngaphaya kobu bushushu.

I-off-gassing ingenzeka xa i-pan ye-polymer ishiywe ingajongwanga.I-polymer pan inokufikelela kwi-383 ° C (721 ° F) kwimizuzu nje emihlanu ifudunyezwe kwisitovu esiqhelekileyo, sombane, itsho i-EWG.

Abathengi ukuba bathathe isigqibo?

Kubalulekile ukuba uqaphele ukuba akukho mveliso yepolymer iye yakhunjulwa e-US, e-Australia okanye naphi na.Ngokubhekiselele kumaqumrhu alawulayo, akhuselekile – ukuba awuwavumeli ukuba atshise ngokugqithisileyo.

Kodwa ukufumanisa ukuba ikhemikhali kwinkqubo yemveliso ichongiwe njengebangela umhlaza, evunyiweyo yinkampani - kunye 'nobunzima' benkampani kunye ne-EPA kwixesha elidlulileyo - kunokuba nesiphumo.

Ingxaki kwiinkampani ezifana neDuPont kukuba, abathengi bayanda ukohlwaya iimveliso kwindawo yentengiso ezibonwa zinophawu lombuzo malunga nokhuseleko lwazo, ngaphandle koqinisekiso lwenkampani ukuba zikhuselekile, nokuba bezikade zisisiseko sabathengi.Cinga imidiza, ukutya okukhawulezayo, kunye nokutya okuziinkozo kwesidlo sakusasa esongezwe iswekile.