Makemikoro—Ishamwari Nomuvengi Here?

TINOFUNGA zvokuita zvakawanda muupenyu nokuenzanisa zvazvakanakira nezvazvakaipira. Somuenzaniso, vanhu vakawanda vanotenga motokari nemhaka yezvainobatsira. Asi pane zvainobatsira izvozvo vanofanira kuyera mutengo wokuva nemotokari yacho—inishuwarenzi, kunyoresa, kuderera kwoukoshi—uye kuichengeta yakasimba zvokugona kufambiswa mumugwagwa. Vanofanira kufungawo nezvengozi yokukuvara kana kuti kufa nemhaka yetsaona. Mamiriro acho ezvinhu akafanana kwazvo nemakemikoro okugadzira—zvaakanakira zvinofanira kuenzaniswa nezvaakaipira. Imbofunga muenzaniso wekemikoro inonzi MTBE (methyl tertiary butyl ether), inowedzerwa mumafuta kuti anyatsotsva uye inoderedza utsi hunobudiswa nemotokari.

Pamwe pacho tinotenda MTBE, mhepo yemumaguta mazhinji muUnited States yakachena kwazvo kupfuura zvayanga yakaita kwemakore akawanda. Asi mhepo yakati chenei “yakatiparira,” inoshuma kudaro New Scientist. Iyi imhaka yokuti MTBE inogona kukonzera kenza, uye yakadzudza mumakumi ezviuru zvematangi okuchengetera peturu epasi pevhu, kazhinji ichisvibisa mvura yepasi. Somugumisiro, rimwe guta zvino rinofanira kuwana 82 muzana yemvura yaro kubva kunze, zvichiita madhora ane mamiriyoni 122,5 pagore! New Scientist inotaura kuti njodzi iyi “ingagona kuva kusvibiswa kwemvura yepasi kwakakomba zvikurusa kweUnited States mumakore akawanda.”

Mamwe makemikoro akarambidzwa ndokurega kutengeswa zvachose nemhaka yokukuvadza kwaanoita nyika yakapoteredza neutano. ‘Asi nei,’ ungabvunza kudaro, ‘izvi zvichiitika? Makemikoro matsva haaongororwi kuti ane chepfu here asati abudiswa?’

Zvinetso Pakuongorora Chepfu

Chokwadi ndechokuti, kuongorora makemikoro kuti ane chepfu here musanganiswa wesayenzi nekufungidzira. “Vanotema kukura kwengozi havazivi pokuisa muganhu pakati pokuwana kemikoro rese rese kune ‘ngozi’ ne‘kusina ngozi,’” anodaro Joseph V. Rodricks mubhuku rake rinonzi Calculated Risks. Ndezvechokwadi kunyange nezvemirimo, yakawanda yacho inoita zvokugadzirwa. “Kunyange kunyatsoongorora chaiko,” inodaro The World Book Encyclopedia, “hakuwanzoratidzi pachena kuti murimo ungangokuvadza zvisingakarirwi.”

Marabhoritari haagoni kuita zvose nemhaka yezvaari. Somuenzaniso, haagoni kutevedzera zvakakwana mashandire achaita kemikoro panze pane mamiriro akasiyana-siyana uye akaoma kunzwisisa. Nyika iri kunze kwerabhoritari yakazara nemazana, kunyange zviuru, zvemakemikoro okugadzira akasiyana-siyana, akawanda acho anogona kusangana-sangana nemamwe uyewo nezvinhu zvipenyu. Mamwe makemikoro aya haakuvadzi pachawo, asi kutoti akasangana pamwe chete, kunze kana kuti mukati memiviri yedu, anogona kugadzira misanganiswa mitsva, ine chepfu. Mamwe makemikoro anova nechepfu, kana kutokonzera kenza chaiko, bedzi kana mitoo yokugaya nayo zvinhu yemuviri yaachinja.

Vanoongorora kukura kwengozi vanoedza sei kutema kana kemikoro yakanaka ipo pane zvinhu zvose izvi zvinonetsa? Mutoo wave uchishandiswa wanga uri wokupa mhuka yemurabhoritari kemikoro yacho uye voedza kushandisa zvavanowana pavanhu. Mutoo uyu wakavimbika nguva dzose here?

Kuedzera Pamhuka Kwakavimbika Here?

Kunze kwekumutsa mibvunzo yekuti zvine unhu here kuitira mhuka utsinye, kuedzera chepfu pamhuka kunomutsa mimwe mibvunzo. Somuenzaniso, mhuka dzakasiyana-siyana dzinowanzoita zvakasiyana dzikapiwa makemikoro. Tushoma shoma twedioxin ine chepfu kwazvo tuchauraya mbira hadzi, asi uwandu humwe chetehwo hunofanira kuwedzerwa kakapetwa ka5 000 kuti iuraye hamster! Kunyange marudzi akada kufanana kwazvo semakonzo nembeva anoita zvakasiyana akapiwa makemikoro.

Naizvozvo kana kuita kwerumwe rudzi rwemhuka kusingatauri chokwadi chezvichaitwa nerumwe rudzi, vanonzvera vanogona sei kuva nechokwadi chokuti imwe kemikoro ichava isina ngozi kuvanhu? Chokwadi ndechokuti, havana chokwadi nazvo.

Vanamazvikokota vemakemikoro zvechokwadi vane basa rakaoma. Vanofanira kufadza vanhu vanoda zvinhu zvavanogadzira, kufadza avo vane basa rokutarisira kugara zvakanaka kwemhuka, uye kugutsa hana dzavo pachavo kuti zvigadzirwa zvavo hazvina ngozi. Nokuda kwezvikonzero izvi, mamwe marabhoritari zvino ari kuedzera makemikoro pamasero omunhu akachengetwa. Zvisinei, nguva ndiyo ichataura kana vimbiso dzechokwadi dzokuti hapana ngozi dzichigona kuitwa.

Apo Kuedza Kwomurabhoritari Kunokundikana

Mushonga wezvipembenene DDT, uchiri kuwanika zvakanyanya munyika yakapoteredza, ndemumwe muenzaniso wekemikoro yakambotaurwa zvisirizvo kuti haina ngozi payakatanga kubudiswa. Masayendisiti gare gare akaziva kuti DDT inogara kwenguva refu iri muchinhu, izvo zvinoitikawo nedzimwe dzingangova chepfu. Migumisiro ine ngozi yeizvi ndeipi? Mudungwe wezvinhu zvinodyanana, unoumbwa nemamiriyoni ezvipuka zvidukuduku, kwouya hove, uye pakupedzisira shiri, mabear, maotter, nezvimwewo, zvinova sefanera benyu, rinowanza chepfu muzvinopedzisira kudya. Zvimwe zvakamboitika ndezvokuti, boka remagrebe, rumwe rudzi rweshiri yemumvura, raisakwanisa kuchechenya kunyange ny’ana rimwe chete zvaro kwemakore anopfuura gumi!

Mafanera aya ezvinhu zvipenyu anobudirira zvokuti mamwe makemikoro, kunyange zvazvo asinganyatsoonekwa mumvura, anowanda zvinoshamisa muzvinhu zvinopedzisira kudya. Mawhale anonzi beluga muRwizi St. Lawrence rweNorth America muenzaniso wakanaka. Ane chepfu yakawanda kwazvo zvokuti anofanira kuonekwa setsvina inokuvadza paanofa!

Mamwe makemikoro ari mumhuka dzakawanda akaonekwa achiita semahomoni. Uye munongova munguva pfupi yapfuura umo masayendisiti akatanga kufushunura kukuvadza kunogona kuita makemikoro aya.

Makemikoro Anoita Semahomoni

Mahomoni inhume dzemakemikoro dzinokosha mumuviri. Anofamba nomuropa redu kuenda kumimwe mitezo yemuviri wedu, kwaanonyandura kana kudzivisa rimwe basa, rakadai sekukura kwemuviri kana kuti simba rokubereka. Zvinofadza kuti, mashoko akabudiswa munhau nguva pfupi yapfuura neWorld Health Organization (WHO) akati “uwandu huri kuramba huchikura hweuchapupu hwezvesayenzi” hunoratidza kuti mamwe makemikoro okugadzira, paanoiswa mumuviri, anovhiringidza mahomoni zvimwe kupfurikidza nokuatevedzera zvinokuvadza kana kuti kuavhara.

Makemikoro anodaro anobatanidza maPCB,a madioxin, mafuran, nemimwe mishonga yezvipembenene, kubatanidza zvinosaririra zveDDT. Achidanwa kunzi zvinokanganisa endocrine, makemikoro aya anogona kukanganisa kushanda zvakanaka kwegadziriro yeendocrine, uko kunobva mahomoni.

Imwe homoni inotevedzerwa nemakemikoro aya ihomoni yevakadzi inodzora kubereka estrogen. Kumwe kunzvera kwakabudiswa mune rimwe bhuku rezvokurapa Pediatrics kunotaura kuti kuwanda kuri kuitika kwekukurumidza kuputudza kwevasikana kungagona kubatanidzwa nemishonga yokugadzirisa bvudzi ine estrogen uyewo makemikoro ari munyika yakapoteredza anoita seestrogen.

Kupa murume mamwe makemikoro pane rimwe danho rinokosha rokukura kwake kunogona kukuvadza zvakakomba. “Kunzvera kwakaratidza kuti,” unodaro mumwe mushumo wemumagazini yeDiscover, “maPCB anopiwa panguva chaiyo yakarurama mukukura anogona kuchinja hambakubvu rume nengwena hono kuva hadzi kana kuti kuva ‘pakati nepakati pekuva hono nehadzi.’”

Mukuwedzera, chepfu yemakemikoro inopedza simba romuviri rokudzivirira hosha, ichisiya mhuka yacho isingatani kubata hosha dzemavhairasi. Zvirokwazvo, hosha dzinokonzerwa nemavhairasi dzinoita sedziri kuramba dzichipararira kupfuura zvadzaiita, kunyanya mumhuka dziri pokupedzisira mumudungwe wezvinhu zvinodyanana, dzakadai semadolphin neshiri dzemumakungwa.

Muvanhu, vana ndivo vanonyanya kukuvadzwa nemakemikoro anoita semahomoni. Vana vakaberekwa nanamai vakadya mafuta emupunga aiva nePCB muJapan makore apfuura “vakanonoka kukura mumuviri nemupfungwa, zvinetso zvemaitiro zvaibatanidza kupusa kana kuti kuchenjeresa, mitezo yokubereka nayo yechirume miduku, uye njere dzakaderera nezvibodzwa zvishanu,” inoshuma kudaro magazini yeDiscover. Kuongororwa kwakaitwa vana vakawana PCB yakawanda muNetherlands uye muNorth America kwakaratidza zvinhu zvakafanana mukukura kwavo kwemuviri nekwendangariro.

Uyewo zvakabatana nemakemikoro aya, inoshuma kudaro WHO, ikenza “dzisingatani kuchinjwa nemahomoni” muvarume nevakadzi, zvakadai seyemazamu, testicular, uye yeprostate. Mukuwedzera, munyika dzinoverengeka, kuwedzera kuri kuoneka kwekushomeka kweurume muvarume, pamwe chete nezvakaita urume hwacho, zvingava nechokuita nekushandisa makemikoro. Mune dzimwe nyika, uwandu hweurume hwatoita sehafu chaiyo yezvahwanga hwakaita makore 50 apfuura!

Munyaya yatangira ino, mumwe chiremba anonzi akataura kuti “chizvarwa chemaedzwa.” Anenge aitaura chokwadi. Chokwadi, zvinhu zvedu zvatakagadzira nemakemikoro zvakatibatsira, asi zvimwe hazvina. Nokudaro, tinenge tachenjera kana tikadzivisa kuwana makemikoro anogona kutikuvadza patinenge tisingafaniri kudaro. Zvinoshamisa kuti, akawanda awo anogona kuwanika mudzimba dzedu. Munyaya yedu inotevera tichakurukura zvatinogona kuita kuzvidzivirira kumakemikoro anogona kutikuvadza.

[Mashoko Omuzasi]

[Mufananidzo uri papeji 27]

Ma“whale” aya ane chepfu yakawanda kwazvo zvokuti anoonekwa setsvina inokuvadza paanofa

[Kwazvakatorwa]

©George Holton, The National Audubon Society Collection/PR