DDT ndeimwe yemakakatanwa akawanda emakemikari munhau yezvino. Yakaratidza kuti inobudirira sein insecticid, asi iyo inonyanyisa tsvina haina kungogumira kuzvipembenene. Kurambidzwa nenyika dzakawanda kusanganisira United States, DDT zvisinei yakashandiswa - zviri pamutemo kana zvisiri pamutemo - mune dzimwe nzvimbo.
Chii chinonzi DDT?
DDT, inonziwo dichloro-diphenyl-trichloroethane, ndeyekirasi yezvipembenene zvinonzi organ organochloride.
Chigadzirwa chemakemikari chinogadziriswa mu laboratori (haisi kuitika mumasikirwo), DDT isina kuchena, yakave yakachena.
DDT haigoni kuparara mumvura; asi, zvisinei, zvinonatswa nyore nyore mumagetsi, mafuta kana mafuta. Somugumisiro wechekuita kwayo yekupedza mumafuta, DDT inogona kuvaka mumafuta matema ezvipfuwo zvinoratidzwa mazviri. Izvi zvakagadzirwa kuvaka-up inozivikanwa sekuti bioaccumulation, uye DDT inorondedzerwa neEPA seinoramba iripo, bioaccumulative toxin.
Nekuda kwekugadzirwa kwehuwandu, DDT inoramba iri muzvokudya, ichibva kune crayfish, matatya, uye hove mumitumbi yemhuka inoidya. Nokudaro, maDDT maitiro anowanzokwirira mumitumbi yemhuka pedyo nechepamusoro pezvokudya, kunyanya kune shiri dzinopisa sezvinoita eagles, marangi, pelicans, condors nedzimwe shiri dzinodya nyama.
DDT inewo hutano hwakakomba pavanhu. Maererano neEPA, DDT inogona kukonzera kukuvadzwa kwechiropa kusanganisira kenza yeropa, nervous system kukuvadza, kuberekwa kwepenital uye zvimwe zvinokuvadza kubereka.
Nhoroondo Pfupfupi yeDDT
DDT yakatanga kugadziridzwa muna 1874, asi haina kusvika muna 1939 kuti Swiss biochemist Paul Hermann Müller akawana simba rayo sechirwere chechinangwa chose. Nokuda kweizvi, Müller akapiwa mubayiro weNobel muna 1948.
Pamberi pekuiswa kweDDT, zvirwere zvakakonzerwa nezvipembenene zvakadai semarariya, typhus, yellow fever, dambudziko rebuonic uye vamwe vakauraya mamiriyoni asingaverengeki evanhu munyika yose.
Munguva yeHondo Yenyika II, kushandiswa kweDDT kwakave kwakakurumbira mumauto eAmerica aida kuitisa zvirwere izvi, kunyanya kuItaly uye munzvimbo dzakasviba seSouth Pacific.
Mushure meHondo Yenyika II, kushandiswa kweDDT kwakapararira sezvo varimi vakawana kubudirira kwayo mukudzivirira zvipembenene zvekurima, uye DDT yakava chido chekusarudza mukurwisa marariya. Zvisinei, dzimwe nyuchi dzakawanda dzakagadziriswa nekurwisana nemushonga.
DDT, Rachel Carson uye "Silent Spring"
Sezvo kushandiswa kweDDT kupararira, masayendisiti mashomanana akacherechedza kuti kushandiswa kwaro kusina maturo kwakanga kuchikonzera kukuvadza kukuru kumhuka dzomusango. Iyi nhau dzakapararira dzakaguma mubhuku razvino rakakurumbira rinonzi Silent Spring nesayendisiti uye munyori Rachel Carson, rinotsanangura ngozi dzekupararira kwemishonga inouraya. (Zita rebhuku rino rinobva pamigumisiro DDT nemamwe makemikari akanga ari kuimba songbirds, izvo zvakanga zvanyangarika mune dzimwe nzvimbo.)
Silent Spring yakava bhuku rakatengesa zvikuru, uye bhuku racho rinowanzoridzirwa nekusimudzirwa kwemazuva ano ezvemhuka . Mumakore akazotevera, masayendisiti munyika yose vakanga vachizivisa kuti shiri dzinenge dzakakwirira dzeDDT mumitumbi yavo dzaiva nekuisa mazai aiva nehombodo dzakapfava dzakaputika vasati vanyangarika, zvichiita kuti shiri dzinopinda.
Uye iyo DDT yakawanda iyo shiri dzaive nadzo mumitumbi yavo, iyo inopisa mazai avo.
DDT Yakarambidzwa Munyika Yose
Sehuchapupu hwekukuvadza, DDT yakanga ichikonzera yakatanga kukura; nyika dzakawanda pasi rose dzakatanga kubvisa kemikemikari kana kuti dzisabhadhara kushandiswa kwayo. Pakazosvika 1970, Hungary, Norway, neSweden zvakanga zvarambidza DDT, uye pasinei nekudzvinyirirwa kukuru kubva kuAmerican chemical industry, kubudiswa nekushandiswa kweDDT zvakarambidzwa muUnited States muna 1972.
Muna 2004, chibvumirano chinozivikanwa seStockholm Convention pamusoro pePisistent Organic Pollutants (POPs), iyo yakasayirwa nenyika 170 inosanganisira United States, yakarambidza kushandiswa kweDDT kuhutachiona hwekudzivirira hutachiona, semuenzaniso, kana chiitiko chekuparara kwemarariya. Mune dzimwe nyika, zvakadaro, DDT ichiri kushandiswa nguva dzose kuti irwise utsi uye zvimwe zvipembenene, uye inoshandiswa mune zvekurima mune dzimwe nzvimbo dzakadai seIndia uye nechokumaodzanyemba kweSahara Africa.