Kuloŵedwa ndi Ululu wa Mtovu Chothetsa Nzeru cha Padziko Lonse
GULU la aulendo la Bambo John Franklin lokayendera Northwest Passage linali pavuto. Zombo zake ziŵiri zinakanirira m’chipale chofeŵa, ndipo nyengo yaitali yachisanu ya ku Arctic inali itangoyamba. Panthaŵiyo nkuti mmalinyero mmodzi atafa kale imfa yosadziŵika bwino—iyeyo anayamba kuchita misala pang’onopang’ono, kubwebweta, ndipo mkupita kwa nthaŵi anawonda kufikira imfa. Kenako misalayo inafalikira. Amuna owonjezereka anamwalira. Pamene akufawo anakwanira khumi ndi aŵiri pazaka ziŵiri zotsatira, ziŵalo zotsala za gulu la aulendowo zinali zotsimikiza kwambiri kusiya zombo zawo kotero kuti zinayamba ulendo wosaphula kanthu kupita chakummwera m’chipululu cha chipale chofeŵa, zikumakoka zoyendera zazikulu zokhala ndi katundu wambiri wosafunikira, ngakhale zinthu zosangalatsa. Palibe chiŵalo chimodzi cha gulu la aulendowo chimene chinapulumuka. Munali m’chaka cha 1848. Kwazaka pafupifupi 140, chochititsa misala yawo chinali chosadziŵika. Koma m’zaka khumi zaposachedwa, kupimidwa kwa tsitsi ndi zidutswa za mafupa kunavumbula chochititsa vutolo chachikulu: mtovu. Amunawo anadya nyama yosungidwa m’zitini zowotchereredwa ndi mtovu. Anafa ndi ululu wa mtovu!
Kuloŵedwa ndi ululu wa mtovu kunali vuto kalelo masiku a ulendo wolepherawo asanafike, ndipo kwakhala chiwopsezo pa umoyo wa padziko lonse chiyambire. M’zaka zaposachedwapa nkhani zambiri zalembedwa ponena za maupandu a kuloŵedwa ndi mtovu. Magulu azaumoyo kuzungulira dziko lonse athedwa nzeru ndi mmene angakuthetsere. Makamaka m’maiko, onga ngati a ku Latin America ndi Kummaŵa kwa Ulaya, kumene kuli malamulo ochepa okhudza malo okhala, kuloŵedwa ndi mtovu kwakhala vuto lomakulakula. Maiko otukuka nawonso akuphatikizidwa.
Zaka khumi zapitazo, podzidzimutsidwa ndi umboni wowonjezereka wakuti nthenda ya kuloŵedwa ndi mtovu inali itafalikira, akulu a zaumoyo ku Australia, Denmark, Jeremani, Mexico, Scotland, ndi United States anayamba kufufuza kuti angodziŵa mmene milingo yaing’ono ya mtovu ingakhaliredi yowopsa kwa anthu, makamaka ana.
Kodi Nkowopsa Motani?
Kodi kukhudza chitsulo wamba kungakhaledi kowopsa? Dr. Richard Wedeen, wolemba bukhu la Poison in the Pot: The Legacy of Lead, amakhulupirira kuti mtovu ungadodometsedi kugwira ntchito kulikonse kwa dongosolo la makhemikolo a m’thupi la munthu. Nchifukwa chake iye ananena kuti “mtovu ungakhale ndiwo umachititsa kuthamanga kwambiri kwa mwazi, sitroko, ndi nthenda ya mtima kudzanso nthenda ya impso.” Wedeen amakhulupirira kuti achikulire ena amene ali ndi nthenda ya kuloŵedwa ndi mtovu kopambanitsa angakhaledi zidakwa ndipo mkupita kwa nthaŵi angabindikiritsidwe m’zipatala za odwala misala.
The World Book Encyclopedia inandandalika zizindikiro zina, zonga ngati kuchepa kwa mwazi, kuwodzera, kuchita dzanzi, kufooka, manjenje, m’mimba, ndi kusanza. “Kuwonongeka kwa ubongo, kukomoka, ndi khunyu zimachitika m’mikhalidwe yoipirapo, ndipo kuloŵedwa ndi mtovu koipitsitsa kwadzetsa imfa,” akusimba motero nazonse ameneyo. Ndipo chiŵerengero chachikulu cha anthu amene amachira atadwala kwambiri amawonongeka ubongo wawo mwachikhalire, akulemba motero dokotala wina wotchuka.
Kodi nchiyani chimene mtovu umachita kuti uyambitse zizindikiro zimenezi? Kwenikweni, thupi silimasiyanitsa mtovu ndi calcium, choncho silimayesa kuutulutsa. Ukumayenda m’mitsempha ya mwazi, mtovu umamka ukuwononga pafupifupi kulikonse umukako. M’mwazi, umalepheretsa kupangidwa kwa hemoglobin, ukumawononga mphamvu ya mwazi ya kunyamula okosijeni. Muubongo ndi m’minyewa, umadziphatika kumaprotini ofunika otchedwa maenzyme ndi kuwalanda mphamvu. Mafupa amasonkhanitsa mtovu ndi kuusunga, nthaŵi zina akumautulutsa pambuyo pa nthaŵi yaitali kuti ukawonongenso zina zambiri.
Mbali ziŵiri za kuloŵedwa ndi mtovu zimakuchititsa kukhala kowopsa kwambiri. Yoyamba, kungakhale mtundu wa nthenda yamachenjera yoloŵa mwapang’onopang’ono, yovuta kutumbidwa. Yachiŵiri, kwakukulukulu chifukwa cha kusintha kwa maindasitale, mtovu uli ponseponse m’malo athu otizungulira.
Chitsulo Chofala
Lerolino, ntchito ya mtovu njochepa mwakuganiza kwa anthu chabe. Mwachitsanzo, kuyambira m’ma 1920 kufikira posachedwapa, matani mamiliyoni ambiri a mtovu awonjezedwa kumafuta a galimoto kuti injini igwire bwino ntchito. Mtovu wagwiritsiridwa ntchito kwambiri muutoto, ngakhale kuti maiko ena tsopano achepetsa kwambiri ntchito yake yotereyi.
Koma ngakhale ngati mumakhala m’dziko limene mtovu wakhala woletsedwa kugwiritsiridwa ntchito muutoto kapena mafuta a galimoto, simungakhaliretu osakhudza mtovu. Mwachitsanzo, mwina mungakhale m’nyumba kapena chipinda chimene chinapakidwa utoto pamene malamulo oterowo anali asanakhalepo. Kapena mwinamwake kumene mumakhala kuli magalimoto akale ambiri amene amagwiritsira ntchito mafuta osanganizana ndi mtovu, amene amatulutsabe utsi wamtovu umene umaipitsa mpweya ndi nthaka yakwanuko.
Ndiyenonso, mtovu wagwiritsiridwanso ntchito kwambiri m’mipope ndi powotcherera. Zinthu zotchinjirizira zamtovu zimagwiritsiridwa ntchito kutetezera akatswiri a X-ray ndi ogwira ntchito zogwirizana ndi mphamvu ya nyukliya kucheza chovulaza. Tiakasupe ta madzi akumwa a m’matanki owotchereredwa ndi mtovu tikali kugwiritsiridwa ntchito, limodzinso ndi zitini za chakudya zolumikizidwa ndi mtovu. Miyala yamtovu imagwiritsiridwa ntchito mofala popanga matambula ndi zikho za vinyo. Ngakhale mabotolo ena a makanda amapangidwa ndi miyala yamtovu. M’mabatiri a galimoto mumakhala mbale zamtovu. Zipolopolo zamtovu za mfuti zimagwiritsiridwa ntchito ndi mamiliyoni a anthu osaŵerengeka. Ndandandayi ikuwoneka kukhala yopanda polekezera.
Ngakhale kuti kuloŵedwa ndi ululu wa mtovu mwa achikulire kukudetsa nkhaŵa kwambiri madokotala, mikhole ya matendawa imene imayambukiridwa mosavuta kwambiri ndiana. Chifukwa ninji ana? Ndipo kodi mungadzitetezere motani inu mwini ndi ana kunthenda yofooketsa thupi ndi yopinimbiritsa maganizo imeneyi?
[Mawu Otsindika patsamba 22]
Kodi kukhudza chitsulo wamba kungakhaledi kowopsa?
[Mawu Otsindika patsamba 22]
Pokhala womasuka kuyenda m’mitsempha ya mwazi, mtovu umamka ukuwononga pafupifupi kulikonse umukako
[Mawu Otsindika patsamba 23]
“Mtovu ungakhale ndiwo umachititsa kuthamanga kwambiri kwa mwazi, sitroko, ndi nthenda ya mtima kudzanso nthenda ya impso”
[Mawu a Chithunzi patsamba 21]
Photo: Painting by Thomas Smith, courtesy of the Maritime Museum, Greenwich, England