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2Template for Humic Substances Research

3Masami Fukushima1*, Kiyoshi Tsutsuki2, and Shunitz Tanaka3,

41 National Institute of Advanced Industrial Science and Technology (AIST), 16-1

5Onogawa, Tsukuba-West, Tsukuba 305-8596, Japan

62 Obihiro University…………………….

7

8 Corresponding author: Tel. & Fax +81-29-861-8328, E-mail [email protected]

9

10Please use line numbers.

1 1 11Abstract

12 To better understand the fate and behavior of hydrophobic organic pollutants (HOPs)

13in aquatic and soil environments, quantitative evaluations of hydrophobic interactions

14between HOPs and humic substances (HSs) are required. The partition coefficients of

15HOPs into dissolved organic carbon (DOC) for HSs …………………

16

17Keywords: Hydrophobic Organic Pollutants…… (within 6 keywords)

2 2 18Introduction

19 Humic substances (HSs) are the most widely distributed terrestrial organic

20materials on the surface of the earth, and are known to be the origin of dissolved organic

21carbon (DOC) in aquatic environments. In general, HSs can be classified into two main

22fractions: humic (HA) and fulvic (FA) acids. HSs have amphiphilic characteristics

23because of the presence of both hydrophilic and hydrophobic moieties in their structures

24(Shinozuka et al., 1987 and 1991). Thus, HSs can act as a surfactant in aqueous

25solutions and such characteristics are crucially important in determining the fate of

26hydrophobic organic pollutants (HOPs) in aquatic and soil environments (Chiou et al.

271979a; Gauthier et al. 1986; Backhus and Gschwend, 1990)……………………

28

29Materials and Methods

30Solubility enhancement

31 It has been reported that the presence of HSs in aqueous solution can result in

32enhancing the apparent water solubility of HOPs. Wershaw et al. (1969) reported that

33the apparent water solubility of DDT in the presence of 0.5% sodium humate was 200

34times larger than that in pure water (5.5 g L-1). This can be attributed to partition-like

35interaction between DDT and the hydrophobic part of dissolved HSs (Chiou et al., 1986

36and 1987)………………

37

38Results and Discussion

39Fluorescence quenching

40 Fluorescence quenching is known to be a quick, elegant, sensitive and reproducible

41method that dose not require complicated pretreatment processes or large amounts of

3 3 42HSs. Thus, this method has been widely applied to the determination of the Kdoc values

43of fluorescent HOPs, such as PAHs. In principal, the fluorescence intensity of HOPs

44decrease with increasing concentration of HSs, and the fluorescence quenching is

45believed to be due to the binding of HOPs to HSs. The Kdoc values are quantitatively

46evaluated according to a Stern-Volmer equation (Gauthier et al., 1986). In the presence

47of HSs, the partition equilibrium of HOPs can be represented as follows:

48 HOP + HS HOP–HS (1)

[HOP - HS] 49 K doc  (2) [HOP]f [DOC]

50where [HOP]f and [HOP–HS] are the concentrations of free and bound species of HOPs

51(M), respectively………………………………………..

52

53Conclusions

54 Measuring Kdoc is central in understanding the role of HSs in the facilitated and/or

55decelerated transport of HOPs in subsurface and surface waters and sedimentary

56porefluids……………………………………….

57

58Acknowledgment

59 This work was supported by Grants-in-Aid for Scientific Research from the Japan

60Society for the Promotion of Science (21310048).

61

62References

63Articles

64Arnold, C.G., Ciani, A., Müller, S.R., Amirbahman, A. and Schwarzenbach, R.P. (1998)

65 Association of triorganotin compounds with dissolved humic acids. Environ. Sci.

4 4 66 Technol. 32, 2976-2983.

67Books

68Gardner, W.S. and Landrum, P.F. (1983) In: Aquatic and terrestrial humic materials,

69 Christman, R.F., Giessing, E.T., Eds.; Ann Arbor Science: Ann Arbor, MI, pp. 203-

70 217.

71Hansch, L. and Leo, A. (1979) In: Substituent Constants for Correlation Analysis in

72 Chemistry and Biology. Elsevier. Amsterdam, pp.516-600.

73Database and Handbooks

74Montgomery, J. H. (1993) In: Agrochemicals Desk Reference, Environmental Data.

75 Lewis Publishers, Chelsea, MI.

5 5 76Figure Captions

77

* 0 78Figure 1. The relationship between Sw /Sw for pyrene and [DOC]. Measurement

0 79conditions: pH 5, ionic strength 0.01, temp. 25°C. The Sw value was evaluated to be 800.59 M, and was used for the parameter in eq. (6). HA, derived from Bibai peat soil, 81was used. The solid line was obtained by the linear regression analysis. 82 83Figure 2. ……………..

6 6 10

8

6 0 w S / * w

S 4

2

0 0.0 2.0x10-5 4.0x10-5 6.0x10-5 8.0x10-5 1.0x10-4 1.2x10-4 [DOC] / kg of C L-1

85

86 Fig. 1

7 7 87Table 1 The logKOW values and the ranges of reported logKdoc values for a variety of HOPs into HSs. 88______a -1 89 Compounds log KOW Kdoc (L Kg ) Methods Literatures 90______91Monoaromatic hydrocarbons 92 1,1'-methylenebis-benzene 4.14 a 3.30 – 3.65 SPME Kopinke, F-D., et al., 1995 93 Stilbene 4.81 a 3.60 – 4.20 SPME Kopinke, F-D., et al., 1995 94 95Polycyclic Aromatic Hydrocarbons (PAHs) 96 Naphthalene 3.37 b 3.02 Dialysis McCarthy and Jimenez, 1985 97 4.28 SPE Brown and Peake, 2003 98 2-Methylnaphthalene 3.87 a 3.40 – 3.65 SPME Kopinke, F-D., et al., 1995 99 Acenaphthylene 4.00 c 3.70 – 4.05 SPME Kopinke, F-D., et al., 1995 100 3.96 SPE Li and Lee, 2000 101 4.34 SPE Brown and Peake, 2003 102 Acenaphthene 3.92 c 3.45 – 3.80 SPME Kopinke, F-D., et al., 1995 103 3.66 SPE Li and Lee, 2000 104 4.17 SPE Brown and Peake, 2003 105______

106a Howard, 1993.

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