TY - JOUR
T1 - Determination of the partition coefficient between dissolved organic carbon and seawater using differential equilibrium kinetics
AU - Kim, Du Yung
AU - Kwon, Jung Hwan
N1 - Funding Information:
This study was supported by Korea Environment Industry & Technology Institute (KEITI) through "The Chemical Accident Prevention Technology Development Project", funded by Korea Ministry of Environment (MOE) (No. 2016001970001 ) and a Korea University grant.
Publisher Copyright:
© 2018 Elsevier Ltd
PY - 2018/9
Y1 - 2018/9
N2 - Because the freely dissolved fraction of highly hydrophobic organic chemicals is bioavailable, knowing the partition coefficient between dissolved organic carbon and water (KDOCw) is crucial to estimate the freely dissolved fraction from the total concentration. A kinetic method was developed to obtain KDOCw that required a shorter experimental time than equilibrium methods. The equilibrium partition coefficients of four polychlorinated biphenyls (PCBs) (2,4,4′-trichlorobiphenyl (PCB 28), 2,2′,3,5′-tetrachlorobiphenyl (PCB 44), 2,2′,4,5,5′-pentachlorobiphenyl (PCB 101), and 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB 153)) between dissolved organic carbon and seawater (KDOCsw) were determined using seawater samples from the Korean coast. The log KDOCsw values of PCB 28 were measured by equilibrating PCB 28, the least hydrophobic congener, with seawater samples, and the values ranged from 6.60 to 7.20. For the more hydrophobic PCBs (PCB 44, PCB 101, and PCB 153), kinetic experiments were conducted to determine the sorption rate constants (k2) and their log KDOCsw values were obtained by comparing their k2 with that of PCB 28. The calculated log KDOCsw values were 6.57-7.35 for PCB 44, 6.23-7.44 for PCB 101, and 6.35-7.73 for PCB 153. The validity of the proposed method was further confirmed using three less hydrophobic polycyclic aromatic hydrocarbons. This kinetic method shortened the experimental time to obtain the KDOCsw values of the more hydrophobic PCBs, which did not reach phase equilibrium. A new kinetic method was proposed to determine KDOCw for more hydrophobic organic chemicals by comparing their desorption rate constants with that for less hydrophobic organic chemical of which KDOCw is measured at equilibrium.
AB - Because the freely dissolved fraction of highly hydrophobic organic chemicals is bioavailable, knowing the partition coefficient between dissolved organic carbon and water (KDOCw) is crucial to estimate the freely dissolved fraction from the total concentration. A kinetic method was developed to obtain KDOCw that required a shorter experimental time than equilibrium methods. The equilibrium partition coefficients of four polychlorinated biphenyls (PCBs) (2,4,4′-trichlorobiphenyl (PCB 28), 2,2′,3,5′-tetrachlorobiphenyl (PCB 44), 2,2′,4,5,5′-pentachlorobiphenyl (PCB 101), and 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB 153)) between dissolved organic carbon and seawater (KDOCsw) were determined using seawater samples from the Korean coast. The log KDOCsw values of PCB 28 were measured by equilibrating PCB 28, the least hydrophobic congener, with seawater samples, and the values ranged from 6.60 to 7.20. For the more hydrophobic PCBs (PCB 44, PCB 101, and PCB 153), kinetic experiments were conducted to determine the sorption rate constants (k2) and their log KDOCsw values were obtained by comparing their k2 with that of PCB 28. The calculated log KDOCsw values were 6.57-7.35 for PCB 44, 6.23-7.44 for PCB 101, and 6.35-7.73 for PCB 153. The validity of the proposed method was further confirmed using three less hydrophobic polycyclic aromatic hydrocarbons. This kinetic method shortened the experimental time to obtain the KDOCsw values of the more hydrophobic PCBs, which did not reach phase equilibrium. A new kinetic method was proposed to determine KDOCw for more hydrophobic organic chemicals by comparing their desorption rate constants with that for less hydrophobic organic chemical of which KDOCw is measured at equilibrium.
KW - Dissolved organic carbon
KW - Equilibrium partition coefficient
KW - Polychlorinated biphenyls
KW - Polydimethylsiloxane
KW - Seawater
UR - http://www.scopus.com/inward/record.url?scp=85046731505&partnerID=8YFLogxK
U2 - 10.1016/j.envpol.2018.04.114
DO - 10.1016/j.envpol.2018.04.114
M3 - Article
C2 - 29734078
AN - SCOPUS:85046731505
SN - 0269-7491
VL - 240
SP - 177
EP - 183
JO - Environmental Pollution
JF - Environmental Pollution
ER -