Inqwaba Yamakhemikhali Enziwe Umuntu

LELI khulu leminyaka lingabizwa kufanele ngokuthi inkathi yesayensi yamakhemikhali. Izinto ezenziwe umuntu ngamakhemikhali ziye zakushintsha ukuphila kwethu. Imizi yethu, amahhovisi namafektri kugcwele izifutho, izinandisi ezisetshenziswa esikhundleni sikashukela, izimonyo, odayi, oyinki, opende, izibulala-zinambuzane, imithi, amapulasitiki, iziqandisi nezindwangu—singabala sithini.

I-World Health Organization (WHO), ithi umkhiqizo womhlaba wonke wamakhemikhali akhiqizwa ngonyaka ukuze kwaneliswe isidingo sezwe salezi zinto ufinyelela ezigidini zezigidi zamaRandi ezingu-9,5. I-WHO ibika ukuthi cishe manje kunamakhemikhali angu-100 000 adayiswayo nokuthi kunezelwa amakhemikhali amasha asukela ku-1000 kuya ku-2000 unyaka ngamunye.

Nokho, ukuba khona kwale nqwaba yamakhemikhali kuphakamisa imibuzo yokuthi ayithinta kanjani indawo ezungezile kanye nempilo yethu. Ngokusobala, sidukuza oswini. “Sonke siyingxenye yesizukulwane esihlolayo, futhi kusazothatha amashumi eminyaka ukuba kwaziwe imiphumela ephelele,” kusho omunye udokotela.

Ingabe Ukwanda Kwamakhemikhali Kusho Ukwanda Kwezingozi?

I-WHO iphawula ukuthi, abantu abahlushwa kakhulu amakhemikhali angcolisayo, “abantu abampofu, abangafundile nabangakwazi ukuthola ukuqeqeshwa okufanele noma ukwaziswa okuyisisekelo ngengozi yamakhemikhali abawasebenzisa nsuku zonke ngokuqondile noma ngenye indlela.” Lokhu kuyiqiniso ngezibulala-zinambuzane. Kodwa amakhemikhali ayasithinta sonke.

Incwadi ethi A Green History of the World, ithi cishe imithombo yamanzi engamaphesenti angu-20 eCalifornia ingcole ngezinga eleqa imingcele yokuphepha, ingcoliswa nayizibulala-zinambuzane. Le ncwadi iyanezela: “EFlorida, imithombo engu-1000 iye yavalwa ngenxa yokungcoliswa; eHungary amadolobha namadolobhana angu-773 anamanzi angakufanelekele ukusetshenziswa, eBrithani amachibi angamaphesenti ayishumi angcoliswe ngezinga eleqa imingcele yokuphepha ye-World Health Organisation futhi ezingxenyeni ezithile zeBrithani ne-United States amanzi asempompini ngeke aphuziswe izinsana ngenxa yokuthi anamazinga aphakeme e-nitrate.”

Isigidi singenye ikhemikhali ewusizo kodwa okungenzeka ibe nobuthi. Ingena endaweni ezungezile ngezindlela eziningi kusukela emapayipini entuthu kuya ezinkulungwaneni zezigidi zokukhanya okuxhophayo. Kungokufanayo nangomthofu, ungatholakala emikhiqizweni eminingi, kusukela kokokubasa kuya kupende. Kodwa nawo ungaba nobuthi njengesigidi, ikakhulukazi ezinganeni. Ukusebenzisa izinto ezikhipha umthofu kunganciphisa “ukuhlakanipha ngamaphuzu amane” enganeni evamile, kusho omunye umbiko ovela eCairo, e-Egypt.

Ngokwe-United Nations Environment Programme, cishe amathani angu-100 esigidi, angu-3800 omthofu, angu-3600 e-phosphate nangu-60 000 ezinto zokukhuculula angena oLwandle iMediterranean ngenxa yezinto ezenziwa umuntu. Kuyaqondakala ukuthi lolu lwandle lusenkingeni. Kodwa alulodwa. Eqinisweni, iZizwe Ezihlangene zamemezela ukuthi u-1998 uwuNyaka WoLwandle Wezizwe Zonke. Ezweni lonke, zonke izilwandle zisenkingeni, ikakhulukazi ngenxa yokungcola.

Nakuba ubuchwepheshe kwezamakhemikhali buye basilethela imikhiqizo eminingi ewusizo, sisebenzisa futhi silahle eminingi yayo ngendlela eyilimaza kakhulu indawo ezungezile. Ingabe siye sazenza “izigqila zentuthuko,” njengoba kwasho omunye umlobeli wephephandaba muva nje?

[Ibhokisi ekhasini 4]

Amakhemikhali Nezinguquko Zamakhemikhali

Elithi “amakhemikhali” lisebenza kuzo zonke izinto eziyisisekelo ezakha izwe elisizungezile, kuhlanganise nezinto eziyinhloko ezingaphezu kwekhulu njengensimbi, umthofu, isigidi, i-carbon, umoya-mpilo ne-nitrogen. Izithako zamakhemikhali, noma inhlanganisela yezinto ezinhlobonhlobo, ihlanganisa izinto ezinjengamanzi, ama-asidi, usawoti ne-alcohol. Eziningi zalezi zithako zixubana ngokwemvelo.

“Inguquko yamakhemikhali” iye yachazwa ‘njengenqubo lapho into ethile iguqulwa amakhemikhali ibe enye into.’ Umlilo uyinguquko yamakhemikhali; uguqula into eshayo—iphepha, uphethiloli, i-hydrogen nokunye—ibe enye into noma izinto ezihluke ngokuphelele. Okuningi kokuxubana kwamakhemikhali kwenzeka ngokungapheli, endaweni esizungezile nangaphakathi kithi.

[Isithombe ekhasini 3]

Abampofu yibo abahlushwa kakhulu amakhemikhali angcolisayo