PCB zatholakala ngekhulu le-19. Ngaleso sikhathi, izimoto zase zisetshenziswa kakhulu futhi isidingo sikaphethiloli sasikhula. Uphethiloli uhlanjululwa emafutheni angahluziwe, futhi inani elikhulu lamakhemikhali, njenge-benzene, likhishwa kule nqubo. Lapho i-benzene ishiselwa, i-chlorine yengezwa ukuze kukhiqizwe ikhemikhali entsha ebizwa ngokuthi i-Polychlorinated biphenyls (PCB). Kuze kube manje, kunezinto ezihlobene ezingama-209 ku-PCB, ezibalwa ngokwenani lama-chlorine ions aqukethe nokuthi zifakwa kuphi.

Imvelo kanye nokusetshenziswa

I-PCB iyikhemikhali yezimboni enezici ezilandelayo:

1. Ukushisa kunamandla, kodwa akukho ukudluliswa kukagesi.

2. Akulula ukushisa.

3. Impahla ezinzile, alukho ushintsho lwamakhemikhali.

4.Ayincibiliki emanzini, yinto enamafutha encibilikayo.

Ngenxa yalezi zakhiwo, i-PCB ekuqaleni yayithathwa njenge-godsend yimboni futhi yayisetshenziswa kabanzi njenge-dielectric, kumadivayisi we-elekthronikhi anjenge-capacitors nama-transformers, noma njengoketshezi lokushintshanisa ukushisa ukulawula izinga lokushisa lapho izinsimbi zisebenza khona.

Ezinsukwini zokuqala, abantu babengazi ngobuthi be-PCBS futhi abazange bathathe izinyathelo zokuphepha, futhi balahla inqwaba yemfucumfucu ye-PCB olwandle. Kwaze kwaba yilapho izisebenzi ezikhiqiza i-PCB ziqala ukugula futhi ososayensi bezemvelo bathola okuqukethwe kwe-PCB ezintweni eziphila emanzini lapho abantu baqala ukunaka izinkinga ezibangelwa i-PCB.

I-PCB ingena kanjani emzimbeni

Imfucuza eminingi ye-PCB inqwabelana ezindaweni zokulahla imfucumfucu, ezingakhulula igesi. Ngokuhamba kwesikhathi, udoti ungagcina ususemachibini noma olwandle. Nakuba i-PCBS ingancibiliki emanzini, iyancibilika emafutheni nasemafutheni, anganqwabelana ezilwaneni zasolwandle, ikakhulukazi ezinkulu ezinjengoshaka namahlengethwa. I-PCBS ihogelwa lapho sidla izinhlanzi zasolwandle olujulile noma okunye ukudla okungcolile, okuhlanganisa imikhiqizo yobisi, amafutha enyama namafutha. I-PCB engenile igcinwa ikakhulukazi esicubuni se-adipose yomuntu, ingadluliselwa kumntwana nge-placenta ngesikhathi sokukhulelwa, futhi iphinde ikhishwe obisini lomuntu.

Imiphumela ye-PCB emzimbeni womuntu

Ukulimala kwesibindi nezinso

Isikhumba sibanga izinduna, ububomvu futhi sithinte umbala

Amehlo abomvu, avuvukele, awakhululekile futhi uketshezi luyanda

Ukukhubazeka kwesistimu yezinzwa, ukukhubazeka kwezandla nezinyawo ukuthuthumela, ukuncipha kwenkumbulo, ukuthuthukiswa kobuhlakani kuvinjiwe

Umsebenzi wokuzala uphazamisa ukukhiqizwa kwamahomoni futhi wehlise ukuzala kwabantu abadala. Izingane zisengozini enkulu yokuzalwa zikhubazekile futhi zikhula kancane kamuva ekuphileni

Umdlavuza, ikakhulukazi umdlavuza wesibindi. I-International Organisation for Research on Cancer ihlukanise i-PCBS njenge-carcinogenic

Ukulawulwa kwe-PCB

Ngo-1976, iCongress yakwenqabela ukwenziwa, ukuthengiswa kanye nokusatshalaliswa kwe-PCBS.

Kusukela ngawo-1980, amazwe amaningana, njengeNetherlands, iBrithani neJalimane, abeke imingcele ku-PCB.

Kodwa noma kunemikhawulo ebekiwe, ukukhiqizwa komhlaba wonke kwakusengamaphawundi ayizigidi ezingama-22 ngonyaka ngo-1984-89. Akubonakali kungenzeka ukumisa ukukhiqizwa kwe-PCB emhlabeni jikelele.

isiphetho

Ukungcoliswa kwe-PCB, okunqwabelene kule minyaka edlule, kungashiwo ukuthi kungokombulunga yonke, cishe konke ukudla kungcoliswe cishe kancane, kunzima ukukugwema ngokuphelele. Esingakwenza ukunaka ukudla esikudlayo, ukuqwashisa nokukhathazeka mayelana nokuvikelwa kwemvelo, futhi ngethemba ukukhuthaza abenzi bezinqubomgomo ukuthi bathathe izilawuli ezifanele.