Qhov sib txawv tseem ceeb ntawm dioxins thiab PCBs yog tias feem ntau cov dioxins yog cov tshuaj tshwm sim hauv ib txwm muaj thiab yeej tsis raug tsim los rau ib lub hom phiaj, hos PCBs yog cov khoom uas tau tsim los rau ntau lub hom phiaj.
Dioxins thiab PCBs yog cov tshuaj lom neeg sib xyaw uas tuaj yeem nyob hauv ib puag ncig, sib sau ua ke hauv cov khoom noj khoom haus. Yog li ntawd, cov no yog cov tshuaj phem. PCBs yog ib tug derivative ntawm dioxins, los yog peb hais tias, PCBs yog ib tug zoo li dioxin compounds. Ob qho tib si dioxins thiab PCBs raug suav tias yog ib puag ncig muaj kuab paug.
Dioxins yog dab tsi?
Dioxins yog ib pawg ntawm cov tshuaj sib xyaw uas suav tias yog cov pa phem ib puag ncig. Feem ntau cov tswv cuab ntawm pab pawg no yog cov tshuaj lom neeg lom zem heev. Cov tebchaw no tau muab ua ke ua ke vim tias lawv cov txheej txheem ntawm kev ua haujlwm ntawm cov tshuaj lom neeg yog tib yam. E.g. Cov tebchaw no zoo li ua kom aryl hydrocarbon receptor (AH receptor) nyob rau hauv sib txawv binding affinities nyob ntawm seb cov qauv tshuaj ntawm dioxin compound.
Daim duab 01: Cov qauv tshuaj ntawm 1, 4-dioxin
Cov tshuaj lom ntawm cov tshuaj dioxin nyob ntawm seb muaj pes tsawg tus chlorine atoms hauv molecule thiab lawv txoj haujlwm. Tus Txheej Txheem Toxic Equivalency Factor (TEF) yog ib lub tswv yim tseem ceeb hais txog cov tshuaj toxicity ntawm dioxin tebchaw. Qhov xwm txheej no tau tsim los pab txhawb kev soj ntsuam kev pheej hmoo thiab kev tswj hwm.
Dioxin compounds zoo li insoluble hauv dej tab sis soluble hauv lipids. Yog li, qhov no ua rau cov tebchaw no tuaj yeem koom nrog cov khoom organic xws li plankton, nplooj nplooj, thiab tsiaj rog. Tsis tas li ntawd, cov tshuaj no zoo li absorbed rau hauv inorganic hais, xws li tshauv thiab av. Cov no yog cov tebchaw ruaj khov heev thiab zoo li sib sau los ntawm cov khoom noj khoom haus.
PCBs yog dab tsi?
PCBs lossis polychlorinated biphenyl tebchaw yog ib pawg ntawm cov organic chlorine compounds uas muaj cov tshuaj formula C12H10-xClx. Cov tebchaw no tau siv dav dav raws li dielectric thiab cov kua dej txias hauv cov khoom siv hluav taws xob, cov ntawv tsis muaj carbonless thiab hauv cov dej hloov hluav taws xob. Cov molar loj ntawm PCBs txawv raws li tus nqi ntawm "x" hauv cov tshuaj formula. Txawm li cas los xij, PCBs tshwm nyob rau hauv lub teeb daj xim lossis tuaj yeem tsis muaj xim. Cov no yog cov kua uas tuab, oily.
Daim duab 02: Cov qauv dav dav ntawm PCBs
PCB cov tebchaw raug suav tias yog cov pa phem uas tuaj yeem ua rau muaj kuab paug ib puag ncig. Vim lawv lub neej ntev, lawv tseem siv tau, tab sis lawv cov khoom lag luam tau poob qis heev txij li xyoo 1960 vim nws qhov toxicity ib puag ncig. Lawv raug cais raws li cov kuab tshuaj tsis tu ncua. Raws li qee qhov kev tshawb fawb tshawb fawb, PCBs tuaj yeem ua rau mob qog noj ntshav hauv cov tsiaj thiab yog cov carcinogens rau tib neeg. Cov tebchaw no tuaj yeem sib sau ua ke hauv cov khoom noj khoom haus, suav nrog ntau tus dej ntws, cov tsev, chaw ua si, thiab lwm qhov chaw.
PCB cov tebchaw yog cov qauv zoo ib yam li cov tshuaj dioxin, thiab lawv cov tshuaj lom neeg ua haujlwm kuj zoo ib yam. Txawm li cas los xij, PCBs tuaj yeem ua rau muaj kev phom sij ntxiv, xws li endocrine cuam tshuam thiab neurotoxicity.
PCB cov tebchaw yog me ntsis soluble hauv dej tab sis soluble hauv cov kuab tshuaj organic. Yog li ntawd, peb tuaj yeem categorize cov tebchaw ua hydrophobic compounds. PCB compounds yog soluble hauv roj, thiab rog thiab. Cov tebchaw no muaj xws li cov xim daj daj daj lossis xim tsis muaj kuab paug uas muaj qhov tsis muaj vapor siab ntawm chav tsev kub. Cov tshuaj no qhia tau hais tias muaj thermal conductivity thiab lub teeb nyem siab.
Zoo ib yam li lwm cov organic ib puag ncig muaj kuab paug, PCBs tsis tawg lossis ua kom yooj yim degradation, ua rau lawv txaus nyiam rau kev lag luam. Cov tebchaw no tiv taus cov kua qaub, hauv paus, oxidation, hydrolysis, thiab kub hloov ib yam. Ntxiv mus, cov tebchaw no tuaj yeem tsim cov tshuaj lom neeg tsis zoo xws li dibenzodioxins thiab dibenzofurans los ntawm ib nrab oxidation.
Qhov tseem ceeb tshaj, cov khoom sib txuas PCB tuaj yeem nkag tau yooj yim thiab nkag mus rau peb cov tawv nqaij, PVC cov qauv, thiab cov qauv latex; Txawm li cas los xij, muaj qee cov ntaub ntawv tiv thaiv PCB zoo li, xws li. Viton, polyethylene, PVA, PTFE, nitrile roj hmab, Neoprene, thiab lwm yam.
Qhov txawv ntawm Dioxins thiab PCBs yog dab tsi?
Dioxins thiab PCB tebchaw yog cov organic paug. Qhov sib txawv tseem ceeb ntawm dioxins thiab PCBs yog tias feem ntau cov dioxins yog cov khoom tshwm sim ib txwm muaj thiab yeej tsis raug tsim los rau ib lub hom phiaj, thaum PCBs yog cov khoom uas tau tsim los rau ntau lub hom phiaj. Yog li ntawd, dioxins twb muaj nyob rau hauv ib puag ncig thaum PCBs raug tso tawm rau ib puag ncig vim tib neeg kev ua ub no.
Hauv qab no yog cov ntsiab lus ntawm qhov sib txawv ntawm dioxins thiab PCBs hauv daim ntawv tabular.
Summary – Dioxins vs PCBs
Dioxins thiab PCBs yog cov sib txuas ruaj khov uas muaj cov tshuaj chlorine atoms txuas nrog cov tshuaj hydrocarbon. Cov no suav hais tias yog cov pa phem organic. Qhov sib txawv tseem ceeb ntawm dioxins thiab PCBs yog tias feem ntau ntawm cov dioxins yog cov khoom tshwm sim ib txwm muaj thiab tsis tau tsim los rau ib lub hom phiaj, qhov PCBs yog cov khoom uas tau tsim los rau ntau lub hom phiaj.
