Ushevu Womthofu—Inkinga Yembulunga Yonke
UMKHANKASO kaSir John Franklin wokuthola umHubhe WaseNyakatho-ntshonalanga odumile wawusenkingeni. Imikhumbi yakhe emibili yayibanjwe yiqhwa, futhi ubusika obude baseArctic babusanda kuqala. Kakade kwase kufe elinye itilosi ngendlela engavamile—laliye lalahlekelwa ingqondo kancane kancane, laqala ukumbongoloza okuhambisana nokudikiza komzimba, futhi ekugcineni lazaca laze lafa. Khona-ke lokhu kuhlanya kwasakazeka. Kwafa amadoda engeziwe. Ngemva kokuba inani eliphakeme labafa lifinyelele kwabangamashumi amabili nane abafa eminyakeni emibili eyalandela, amalungu alomkhankaso asinda ayesezimisele kakhulu ukushiya imikhumbi yawo kangangokuba aqalisa uhambo ephelelwe ithemba elibhekise eningizimu enqamula enkangala ethaphuka iqhwa, edonsa izihlibhi ezinkulu ezithwele izimpahla eziningi ezingadingekile, ngisho nezinto zokunethezeka. Akukho nelilodwa ilungu lalomkhankaso elasinda. Kwakungo-1848. Eminyakeni ecishe ibe ngu-140, imbangela yokugula kwawo yayiyimfihlakalo. Kepha eshumini leminyaka elidlule ukuhlola okwenziwa ezinweleni nezimveva zamathambo kwembula isici esiyisihluthulelo salempicabadala: umthofu. Lamadoda ayedle inyama eyayigcinwe emathinini ayevalwe ngomthofu. Ayengenwé ushevu womthofu!
Kudala ngaphambi kwalezozinsuku zomkhankaso owabhuntsha ushevu womthofu wawuyinkinga, futhi kusukela ngalesosikhathi uye wakhulela ekubeni usongo lwempilo yembulunga yonke. Eminyakeni yamuva nje kuye kwalotshwa insada yezincwadi ngezingozi zoshevu womthofu. Izinhlangano zezempilo emhlabeni jikelele zisenkingeni yokuthi zingabhekana kanjani nawo. Ikakhulukazi emazweni, njengalawo aseLatin America naseMpumalanga Yurophu, lapho kunezinto ezilinganiselwe kuphela zokuvikela indawo ezungezile, ushevu womthofu uye waba inkinga eyandayo. Amazwe athuthukile nawo akhathazekile ngokufanayo.
Zethuswe ubufakazi obukhulayo bokuthi ushevu womthofu wawube yisifo esisakazeke kabanzi, eshumini leminyaka elidlule, izikhulu zezempilo zaseAustralia, eDenmark, eJalimane, eMexico, eScotland, naseUnited States zaqala ukwenza ukuhlola ukuze zithole ukuthi ngisho namazinga aphansi kakhulu omthofu ayeyingozi kangakanani kubantu, ikakhulukazi ezinganeni.
Uyingozi Kangakanani?
Ingabe ukungavikeleki ensimbini evamile kungaba yingozi kangako ngempela? UDkt. Richard Wedeen, umlobi wethi Poison in the Pot: The Legacy of Lead, ukholelwa ukuthi umthofu ungase wonakalise ukusebenza kwaso sonke isimiso esivikelayo somzimba womuntu. Ngakho-ke uphetha ngokuthi “umthofu ungase uhlanganiswe nomfutho wegazi ophakeme, isifo sokufa uhlangothi, nokuhlaselwa inhliziyo kanye nesifo sezinso.” UWedeen ukholelwa ukuthi abantu abadala abathile abanoshevu womthofu omningi bangase babe ngisho nayimilutha yotshwala futhi bagcine besezikhungweni zokugcinwa kwezinhlanya.
IWorld Book Encyclopedia ibala ezinye izimpawu, njengokuntuleka kwamangqamuzana abomvu egazi, inzululwane, ukubanjwa amajaqamba, ukuphelelwa amandla, ukukhubazeka, ubuhlungu besisu, nokuhlanza. “Ukulimala kobuchopho, ukuquleka, nokudikiza kwezicubu kwenzeka ezimweni ezibucayi kakhulu, futhi ukungenwa kakhulu wushevu womthofu kuye kwabangela ukufa,” kubika le-encyclopedia. Futhi isilinganiso esiphawulekayo salabo abalulama ezimweni ezibucayi baphathwa ukukhubazeka kokulimala kobuchopho, kubhala omunye udokotela owaziwayo.
Yini ngempela umthofu oyenzayo ukuze uveze lezimpawu? Eqinisweni, umzimba ngephutha uthatha umthofu njengecalcium, ngakho awenzi mzamo wokuwukhipha. Njengoba uzula emithanjeni yegazi, umthofu ubangela umonakalo nomaphi nje lapho uhamba khona. Egazini, uvimbela ukukhiqizwa kwehemoglobin, ukhubaza ikhono legazi lokuthwala umoya-mpilo. Ebuchosheni nasesimisweni sokusebenza kwezinzwa, ubambelela kumaprotheni ayinhloko okuthiwa amaenzyme futhi uwenze angasebenzi. Amathambo aqoqa umthofu futhi awugcine, ngezinye izikhathi awukhiphe sekwephuze kakhulu ukuze wenze umonakalo owengeziwe.
Kunezici ezimbili zoshevu womthofu ezenza ukuba ube yingozi ngokukhethekile. Okokuqala, kungaba uhlobo lwesifo olunobuqili noluvela ngokunyenya, okunzima ukulubona. Okwesibili, ikakhulukazi ngenxa yezinguquko ezingokwezimboni, umthofu cishe ngokuphelele ukuyo yonke indawo yethu ezungezile.
Insimbi Ekuyo Yonke Indawo
Namuhla, ukusetshenziswa komthofu kulinganiselwa kuphela ukucabanga komuntu. Ngokwesibonelo, kusukela ngawo-1920 kuze kube muva nje, izigidi zamathani omthofu ziye zenezelwa kuphethiloli ukuze kuthuthukiswe ukusebenza kwezinjini. Umthofu uye wasetshenziswa kakhulu kupende, nakuba amanye amazwe manje eye akulinganisela kakhulu lokhu kusetshenziswa.
Kodwa ngisho noma ngabe uhlala ezweni lapho sekuyisikhathi eside umthofu wenqatshelwa khona ukusetshenziswa kupende noma kuphethiloli, kungase kwenzeke awulondekile ngokuphelele ekubeni ongavikelekile emthofini. Ngokwesibonelo, ungase uhlale endlini noma isakhiwo esapendwa ngaphambi kokuba imithetho enjalo iqale ukusebenza. Noma mhlawumbe lapho uhlala khona kunezimoto eziningi zohlobo oludala ezisasebenzisa uphethiloli ofakwe umthofu, ezisakhipha intuthu engcolisa umoya nenhlabathi ekuzungezile.
Khona-ke, futhi, umthofu uye wasetshenziswa kakhulu ekufakeleni amapayipi nasekushiseleni izinsimbi. Izinto zokuvikela ezenziwe ngomthofu zisetshenziselwa ukuvikela izazi ezingochwepheshe beX-ray nezisebenzi zamandla enuzi ekukhishweni kwemisebe eyingozi. Imithombo yokuphuza enamathange amakhulu avalwe ngezivalo zomthofu isasetshenziswa, njengoba kunjalo nangamathini okudla anezivalo ezihlanganiswe ngomthofu. Imihlobiso ecwebezelayo yomthofu ivamile ezingilazini zewayini nasezitsheni. Ngisho namanye amabhodlela ezinsana enziwe ngemihlobiso ecwebezelayo yomthofu. Kunezingcwecwe zomthofu kumabattery ezimoto. Izinhlamvu zomthofu nohlwaye lwesibhamu kusetshenziswa izigidi ezingenakubalwa. Loluhlu lubonakala lungenakuphela.
Nakuba ushevu womthofu phakathi kwabantu abadala ukhathaza ngokungathi sína kwezokwelapha, izisulu ezingavikelekile ngempela zalesifo abantwana. Kungani kungabantwana? Futhi ungazivikela kanjani wena nabo kulesifo esithena amandla ngokomzimba nangokwengqondo?
[Amazwi acashunwe esihlokweni ekhasini 4]
Ingabe ukungavikeleki ensimbini evamile kungaba yingozi kangako ngempela?
[Amazwi acashunwe esihlokweni ekhasini 4]
Njengoba uzihambela ngenkululeko emithanjeni yegazi, umthofu ubangela umonakalo nomaphi nje lapho uhamba khona
[Amazwi acashunwe esihlokweni ekhasini 5]
“Umthofu ungase uhlanganiswe nomfutho wegazi ophakeme, isifo sohlangothi, nokuhlaselwa inhliziyo kanye nesifo sezinso”
[Umthombo Wesithombe ekhasini 3]
Photo: Painting by Thomas Smith, courtesy of the Maritime Museum, Greenwich, England