Geoscience Reference
In-Depth Information
molecular weight and structure information. 131 More detailed information about
estimating these coefficients is available in SPARC. 145
Values for partition coefficients can be obtained from laboratory experiments.
As stated earlier, laboratory studies have shown that the partition coefficient is related
to the hydrophobicity of the chemical and organic matter content of the sediment
for organic chemicals. Many organic pollutants of current interest are nonpolar,
hydrophobic compounds whose partition coefficients correlate quite well with the
organic fraction of the sediment. Karickoff et al. 146 and Schwarzenbach and Westall 147
have developed empirical expressions relating equilibrium partition coefficients to
laboratory measurements, leading to fairly reliable means of estimating appropriate
values for K oc as given below:
Karickhoff et al. 146
log K oc : 1.00log K ow - 0.21
(4.39)
Schwarzenbach and Westall 147
log K oc : 0.72log K ow
+
0.49
(4.40)
These relationships have proven very useful for predicting equilibrium partition
coefficients of a great number of neutral hydrophobic organic compounds between
water and natural sorbents of very different origins. Other chemical property esti-
mation methods are reported by Lyman et al. 148 Table 4.39 provides a list of measured
log K ow values for a number of organic chemicals of environmental interest. Deter-
mination of K ow values for organic chemicals needs experimental analysis. Recent
data on such values may be found in BCPC, 116 EXTOXNET, 118 and the Merck
Index. 149
TABLE 4.39
Octanol/Water Partition Coefficients of Some Selected Organics
Chemical
log K ow
As Cited in
Bromoform
2.3
Schnoor et al. 150
Carbofuran
1.60
Schnoor 131
Carbofuran
17-26
DPR 117
Chloroform
1.90-1.97
Schnoor 131
Chloroform
1.97
Schnoor et al. 150
Chloroform
6.22
Merck Index 149
2-Choloroethyl vinyl ether
1.28
Schnoor 131
2-Choloroethyl vinyl ether
4.08-4.28
Kidd and James 151
DDT
6.4
Schnoor 131
DDT
3.98-6.36
Pontolillo and Eganhouse 152
Ethylbenzene
3.34
Schnoor et al. 150
Hexachlorobenzene
6.41
Schnoor et al. 150
Pentachlorophenol
5.01
Schnoor 131
2-Nitrophenol
1.75
Schnoor et al. 150
Tetrachloroethylene
2.88
Schnoor et al. 150
 
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