- Email: [email protected]
Seasonal flux of nonylphenol in Han River, Korea
Chemosphere 56 (2004) 1–6 www.elsevier.com/locate/chemosphere
Seasonal flux of nonylphenol in Han River, Korea Donghao Li
a,*
, Minseon Kim a, Won Joon Shim a, Un Hyuk Yim a, Jae-Ryoung Oh a, Young-Jin Kwon b
a
b
South Sea Institute, Korea Ocean Research and Development Institute, Jangmok-myon 391, Geoje-shi, Gyungsangnamdo 656-834, South Korea Department of Environmental Science, Kangwon National University, 192-1 Hyoja-dong, Chunchon 200-701, South Korea Received 14 October 2003; received in revised form 7 January 2004; accepted 27 January 2004
Abstract In order to understand the behavior of nonylphenol (NP) in Han River, water, suspended particle and sediment samples were analyzed during summer, autumn and winter. Concentrations of nonylphenol in water ranged from 23.2 to 187.6 ng/l, in suspended particle from 6.8 to 190.8 ng/l and in sediment from 25.4 to 932.0 ng/g dry wt. An increasing trend in the concentration is noticed in all matrices along down the river. In case of water and suspended particle, concentrations were higher in warmer season than in colder season. Percentage of nonylphenol in the suspended particle phase decreased from 67% to 28% with decreasing temperature in water. A reasonable correlation (R2 ¼ 0:63) was obtained for water and suspended particle. The partition coefficient Log Kp is 4.8. No seasonal variation of the concentration in sediment is noticed in this study. Ó 2004 Elsevier Ltd. All rights reserved. Keywords: Alkylphenols (APs); Nonylphenol (NP); Endocrine disruptor chemical; River
1. Introduction Nonylphenol is an endocrine disruptor. It is a degradation product of alkylphenol polyethoxylates (APnEOs) that is used in the world as nonionic surfactant and detergent in industrial and domestic applications over the last five decades (Giger et al., 1984). Due to persistence in the environment, it is bioconcentrated in organisms. In fact, high levels of nonylphenol were found from seafood and fish caught in Italian coast and Japanese rivers, respectively (Ferrara et al., 2001; Tsuda et al., 2001). Although the APnEOs are less toxic to human and organisms, the degradation products such as nonylphenol is toxic with hormone like properties. Yadetie and Male (2002) and Hemmer et al. (2002) reported that
*
Corresponding author. Tel.: +82-55-639-8671; fax: +82-55639-8689. E-mail address: [email protected] (D. Li).
nonylphenol has adverse effect on fish hormone system even at low concentrations. In order to avoid any adverse toxic effect on humans and biota, many countries have banned or regulated recently the production and application of APnEOs (Renner, 1997; Isobe et al., 2001). Though APnEOs have been in use for several decades, research on nonylphenol that helps to regulate these chemicals is hardly found in Korea. As a result, high levels of nonylphenol were found in several river estuaries and lakes in Korea. For examples, we reported in a recent paper (Li et al., 2004) that the average concentration of nonylphenol in creek water was 3.6 lg/l. Khim et al. (1999) reported nonylphenol concentrations ranging from 20.2 to 1820 ng/g dry wt in Shihwa Lake sediments. However, there is no reported data in riverine system though most of APnEOs is disposed as surfactant and detergent, directly into aquatic systems such as rivers, lakes and seas via drainage. In fact, the rivers are the major transport media of alkylphenol pollutants in Korea.
0045-6535/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2004.01.034
2
D. Li et al. / Chemosphere 56 (2004) 1–6
Han River is the longest and biggest in Korea. It flows over a distance of 482 km, with an area of 26 000 km2 . The average depth of the river in the center is about 6 m. It supplies drinking water to over twenty millions people living around the river. Among them, twelve millions live in Seoul City. Several sub-streams of Han River pass through the city. As a result, this river accumulates large amount of wastewater and sewage from Seoul. It is doubtful that the Seoul wastewater facility removes these compounds before allowing the drainage to the river (on the contrary, the warm water condition in the facility promotes degradation of APnEOs to nonylphenol). The chemical burden of nonylphenol increases tremendously during monsoon season with heavy floods when wastewater is discharged directly into the river. The capacity of the plant is insufficient to treat the large volume of waste water produced during the rainy seasons. According to Korean Environmental Ministry report in 2001, the COD and BOD ranged from 3.8 to 59.4 and from 0.8 to 19.7 mg/kg, respectively, and the suspended particle in the river ranged from 4.4 to 20.0 mg/l (Ministry of Environment Republic of Korea, 2002). In order to understand quantitatively the distribution and behavioral characteristics of phenolic compounds in the Han River environment, nonylphenol was determined from water, suspended particle and sediment samples in this study. Modeling of nonylphenol in the Han River environment is essential for regulation of these compounds in the Korean environment. One such modeling study was carried out in our laboratory and in Seoul University recently.
2. Materials and methods 2.1. Solvents and standards All organic solvents including acetone, dichloromethane and hexane were of pesticide grade and were purchased from Caledon (Canada). Nonylphenol, silylation reagent BSTFA (N,O-bis(trimethylsilyl) trifluoroacetamide), surrogate standard (bisphenol A-d14), gas chromatography internal standards (GCIS) including naphthalene-d8, phenanthrene-d10 and pyrene-d10 were obtained form Chem Service (USA). The purity of all standards was up to 98%. HCl was purchased from Merck. Florisil was obtained from Supelco. In order to remove contaminants, the Florisil, Glass Fiber Filter and aluminum foil were burned at 450 °C for 12 h, then Florisil was activated at 120 °C until used and Glass Fiber Filter and aluminum foil were stored in vacuum desiccator. The copper was obtained from Merck, it was used to remove sulfur from the environmental sample extract after activating with concentrated HCl. All standards were prepared at 100 mg/l as a stock solution
with hexane acetone mixture (1:1). It was diluted approximately to calibration standards, surrogate standard (2 mg/l) and gas chromatography internal standard (GCIS) (2 mg/l) with acetone. 2.2. Sampling sites and sample collection In order to understand spatial distribution of nonylphenol in overall Han River, sediment samples were collected from ten sites in Aug. 2001 as shown in Fig. 1. Among them, site CC, CP, YZ, YP and PD were located in upstream, site KP, TY and KH were located in downstream, site KN and MW were located in the Seoul City vicinity. In order to study seasonal flux of nonylphenol in Han River, the study focused on KN and MW, and the sites were divided into five stations, respectively. Water, suspended particle and sediment samples were collected seasonally at these sites. The average water temperature in Aug., Oct. and Dec. were 27, 19 and 5 °C, respectively. One liter of filtered water sample (0.45 lm) was collected in 1 l glass bottle with Teflon lined cap. It was acidified to 0.01 M with 6 M HCl in order to protect it from biodegradation and to increase the stability of target phenolic analytes. The water samples were analyzed within 3 days. The filtered suspended particle matrix were wrapped with aluminum foil and stored in a glass bottle at )20 °C until analyzed. The surface sediment samples were sampled with van Veen Grap, then collected in glass bottle with Teflon lined cap and stored at about )20 °C until analysis. 2.3. Extraction and analysis Water, suspended particle and sediment samples were treated according to methods reported by Li et al. (2001, 2003). The brief analytical procedures were as follows. Acidified water samples were extracted using liquid liquid extraction (LLE) with dichloromethane after addition of appropriate amount of surrogate internal standard. The extracts were concentrated to 2 ml with rotary evaporator at 35 °C and reduced pressure. It was concentrated again with a gentle flow of dry nitrogen following addition of acetone in order to carry out fast silyl derivatization. It was submitted to on column derivatization and Florisil cleanup. Six milliliters of hexane was used as eluent. The concentrated eluents were analyzed by gas chromatography (Shimadzu GC17A)–mass spectrometry (Shimadzu MS QP-5000) with selected ion monitoring mode after addition of 200 ng of GCIS. Conditions of GC/MS analysis were described in a previous report (Li et al., 2001). Wet suspended particle and 3 g of wet sediment samples were treated into a solid suspension by adding appropriate amount of 0.1 M HCl solution. It was digested for 10 min, and then extracted three times using shaking technique with three portions of 5 ml dichloromethane. The combined extract
D. Li et al. / Chemosphere 56 (2004) 1–6
3
Fig. 1. Location of sampling sites.
was concentrated to about 1 ml under a gentle dry nitrogen flow. In order to remove water and sulfur from the extract, anhydride sodium sulfate and copper were added sequentially into the extract. The extract was transferred into another glass vial that was cleaned previously with two rinsing of dichloromethane. It was concentrated again to 0.2 ml under a gentle flow of dry nitrogen, and then 1 ml of acetone was added to the concentrated extract. It was concentrated further to 0.5 ml. Following processes including derivatization, clean-up and concentration steps were same with in water sample treatment.
3. Results and discussion In Aug. 2001, sediment samples were collected in Han River, from upstream to downstream as indicated in Fig. 1. The results are shown in Fig. 2. Nonylphenol concentrations ranged from 46 to 256 ng/g dry wt. Levels
Concentration (ng/g dry wt.) of nonylphenol in sediment
250 200 150 100 50 0 CC
CP
YZ upstream
YP
PD
KN
MW
Seoul city
KP
TY
KH
Downstream
Sampling site along the river flow down
Fig. 2. Nonylphenol distribution in the sediment of the Han River.
of nonylphenol recorded in downstream river were generally higher than in the upstream. Though an increasing trend was noticed just downstream the city of Seoul, a dramatic increase in concentration was noticed in locations near Seoul City. This is up to five times, the concentration noticed elsewhere. This might be due to discharge of effluents containing large amount of sewage and wastewater from Seoul City. In order to understand seasonal distribution levels of nonylphenol in Han River, water, suspended particle and sediment samples were analyzed in Aug. (warmer), Oct. (medium), Dec. (colder) in 2001. As listed in Table 1, concentration levels of nonylphenol in water decreased with decreasing water temperature and in summer is generally two times higher. Usage of APnEOs in general and the activity of microorganism in the riverine system may play a role on the levels of nonylphenol. Among them, the amounts of APnEOs used are not likely to change during seasons and hence the seasonal variation of nonylphenol levels noticed in our study is principally due to microbial activity. Several papers reported that APnEOs have rapidly degraded into nonylphenol and shortened alkylphenol ethoxylates at high temperature, while the degradation rate becomes very slow at low temperature (Tanghe et al., 1998; Staples et al., 1999; Manzano et al., 1999). The concentration of nonylphenol showed not only seasonal flux but showed a spatial trend as well. Levels of nonylphenol increased in the downstream water in all seasons as shown in Table 1. For example, over 100 ng/l (except St 7) of nonylphenol were determined at the downstream site in Aug., while less than 85 ng/l (except St 5) of it was found at the upstream site in the same season. Ding et al. (1999) and Sabik et al. (2003) in the Lao-Jie and St. Lawrence River reported similar trends, respectively. The river after passing through the city gets
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D. Li et al. / Chemosphere 56 (2004) 1–6
Table 1 Concentrations of nonylphenol in water, suspended particle and sediment from Han River in 2001 Site St1 St2 St3 St4 St5 St6 St7 St8 St9 St10 b
Suspended particle (ng/l)
Sediment (ng/g dry wt)
Aug.
Oct.
Dec.
Aug.
Oct.
Dec.
Aug.
Oct.
Dec.
83.0 NAa 71.4 83.1 109.7 104.5 79.0 105.2 187.6 100.7
42.0 46.2 44.6 56.3 60.2 50.3 70.9 68.5 76.5 84.1
23.2 17.3 72.0 36.7 20.3 50.8 27.9 55.7 71.3 56.9
123.5(5.9)b 190.8(9.5) 115.9(3.8) NA 130.8(9.2) 151.0(8.9) 133.1(7.1) 109.6(9.5) 156.1(16.6) 160.1(7.9)
18.0(1.4) 26.0(1.1) 18.0(6.2) 22.0(9.3) 34.0(5.9) 28.0(1.9) 44.0(1.9) 48.0(3.1) 60.0(2.2) 56.0(3.3)
20.9(6.9) 6.8(1.6) 7.8(2.3) 17.1(4.3) 13.4(2.8) 20.4(4.2) 26.0(2.8) 14.4(1.0) 20.4(2.3) 23.0(2.6)
114.3 87.4 95.4 69.8 56.3 231.2 249.7 356.5 235.0 207.6
79.6 81.3 35.1 194.1 85.0 305.2 550.2 144.5 228.0 732.4
67.3 40.3 116.8 25.4 44.9 249.3 374.7 411.8 259.3 932.0
NA means not analyzed. Concentration (lg/g dry wt) was normalized by dry weight of suspended particle.
contaminated thus showing high levels along the downstream. Nonylphenol, the degradation product of APnEOs, is relatively hydrophobic compared with its parental compound that is readily water-soluble as detergents and surfactants. So nonylphenol is readily adsorbed on surfaces of suspended particle and sediment in aquatic systems, for a long period. Table 1 shows concentrations of nonylphenol in suspended particles that ranged from 1.0 to 6.9 in Dec., from 1.1 to 9.3 in Oct. and from 3.8 to 16.6 lg/g dry wt in Aug. The levels of nonylphenol in suspended particle varied by season and increased along the downstream water in all seasons except a few sites. High concentrations of nonylphenol were found in warmer season, and the concentrations reduced with decreasing water temperature resulting in low concentration in winter. Takada et al. has reported similar results in the investigation of nonylphenol from the Shiwada River, the average concentration of nonylphenol in suspended particle are 3.54 lg/g dry wt and the concentrations varied by season. As described above, the behavior of nonylphenol in water showed similar trend. It indicates that equilibrium of nonylphenol in water and suspended particle is reached rapidly and that primarily affect the concentration levels of nonylphenol in suspended particle. In such a case, reasonable correlation of nonylphenol in water and suspended particle is expected. Our results are presented in Fig. 3. In which, the partition coefficient was obtained as following: Log Kp ¼ Log Css dry wt=Cw : The Css and Cw are representing concentration of nonylphenol in suspended particle and in water, respectively. Calculated average of Log Kp is 4.8 with 13.5 of relative standard deviation. Since there is reasonable seasonal and spatial trend correlation of nonylphenol distribution profile in water and suspended particle, a
250
NP in suspended particle
a
Water (ng/l)
200 2
R = 0.63
150 100 50 0
0
50
100
150
200
NP in water
Fig. 3. Correlation of nonylphenol in water (ng/l) and suspended particle (ng/l).
reasonable correlation (R2 ¼ 0:63) was obtained. It clearly indicates that nonylphenol was readily absorbed to suspended particle in the Han River water system. In the Han River, over 60% of nonylphenol were found in suspended particle phase in Aug. as shown in Fig. 4. This decreased with decreasing temperatures in the winter. This could also be due to the fact that high particle concentrations are usually seen in the rainy season (Aug.) and low concentrations in the dry season (Dec.). The nonylphenol level in suspended particle in our study is two times higher than those reported by others. In the Tamagawa river and the Sumidagawa river in Japan, only about 20% of nonylphenol were found in the suspended particle due to effective removal of suspended particles during sewage treatment processes (Isobe et al., 2001). These contaminated suspended particles settle finally into the bottom of the river. It is reasonable to expect that large amount of nonylphenol is present in the sediment of the Han River as well. In fact high concentrations of nonylphenol were detected from the sediment. The nonylphenol ranged from 25.4 to 932.0 ng/g dry wt
Percentage (%) of nonylphenol
D. Li et al. / Chemosphere 56 (2004) 1–6
accumulation and persistence in the long term is not negligible. In order to protect humans and biota from the environmental effect of nonylphenol, selective removal of suspended particle from the Han River and restrictions on the usage and discharge of APnEOs are necessary.
100 suspended particle
80 60 40
water
Acknowledgements
20 0
5
Aug.
Oct.
Dec.
Sampling date
Fig. 4. Percentage of nonylphenol in water and suspended particle.
as shown in Table 1. Seasonal variation of nonylphenol as seen in water and particles are not seen with sediments (Figure not shown). The spatial distribution indicates an increasing trend in river sediment, downstream. This is at least three times higher downstream than those found in the upstream sampling sites. It indicates that most of the nonylphenol adsorbed by suspended particle during the river flow thorough the Seoul City settled finally to the bottom. The average partition coefficient (Log Kp ) calculated from the every site and season ranged from 2.7 to 4.2. There is no reasonable correlation between nonylphenol in sediment and water (R2 ¼ 0:02) (Figure not shown). This might be due to (1), flow rate of Han River is relatively fast, not allowing time for equilibrium partitioning (2), degradation rates of nonylphenol and its mother compound APnEOs in the water are significantly faster than those in sediment. (3), concentration of nonylphenol in water varied through seasons. Various factors such as temperature, flow rate, sedimentation rate, and particle size etc., may affect concentration of nonylphenol in sediment and water and a detailed study is needed to understand this fully. Although measured average concentrations of nonylphenol in water, suspended particle and sediment are much lower than reported acute toxicity levels, some individual values in suspended particle are nearly the same as that of reported toxic levels. Regulatory levels of nonylphenol in USA and Europe are 1 lg/l in water (Renner, 1997). Naylor (1995) reported that the lowest effective concentration of nonylphenol in shrimp for subacute toxicity is 26 ng/g dry wt in sediment. The threshold level of nonylphenol for fish vitellogenin stimulation is 1 lg/l (Schwaiger et al., 2002). Nice et al. (2000) also reported that the exposure of Pacific oyster larvae, Crassostrea gigas, to nonylphenol is as low as 0.1 lg/l causing delay in development and a significant decrease in survival rate. Based on those reports, levels of nonylphenol in suspended particle might be potentially hazardous to organisms in the river. In addition, the effect on humans and other aquatic organisms through
The authors are grateful to Dr. Narayanan Kannan for his valuable comments on our manuscripts. This study is a part of a project supported by National Institute of Environmental Research, Korea (Project No. PG333-00). We thank the captain and crews of boats in the Han River Management Office for helping the sample collection.
References Ding, W.H., Tzing, S.H., Lo, J.H., 1999. Occurrence and concentrations of aromatic surfactants and their degradation products in river waters of Taiwan. Chemosphere 38, 2597–2606. Ferrara, F., Fabietti, F., Delise, M., Bocca, A.P., Funari, E., 2001. Alkylphenolic compounds in edible molluscs of the Adriatic sea (Italy). Environ. Sci. Technol. 35, 3109–3112. Giger, W., Brunner, P.H., Schaffner, C., 1984. 4-Nonylphenol in sewage sludge: accumulation of toxic metabolites from nonionic surfactants. Science 225, 623–625. Hemmer, M.J., Bowman, C.J., Hemmer, B.L., Friedman, S.D., Marcovich, D., Kroll, K.J., Denslow, N.D., 2002. Vitellogenin mRNA regulation and plasma clearance in male sheepshead minnows, (Cyprinodon variegatus) after cessation of exposure to 17b-estradiol and p-nonylphenol. Aquat. Toxicol. 58, 99–112. Isobe, T., Nishiyama, H., Nakashima, A., Takada, H., 2001. Distribution and behavior of nonylphenol, octylphenol, and nonylphenol monoethoxylate in Tokyo metropolitan area: their association with aquatic particles and sedimentary distribution. Environ. Sci. Technol. 35, 1041–1049. Khim, J.S., Villeneuve, D.L., Kannan, K., Lee, K.T., Snyder, S.A., Koh, C.H., Giesy, J.P., 1999. Alkylphenols, polycyclic aromatic hydrocarbons, and organochlorines in sediment from Lake Shihwa, Korea: Instrumental and bioanalytical characterization. Environ. Toxicol. Chem. 18 (11), 2424– 2432. Li, D., Oh, J.R., Park, J., 2001. Silyl derivatization of alkylphenols, chlorophenols, and bisphenols A for simultaneous GC/MS determination. Anal. Chem. 73, 3089–3095. Li, D., Oh, J.R., Park, J., 2003. Direct extraction of alkylphenols, chlorophenols and bisphenol A from acid-digested sediment suspension for simultaneous gas chromatographic–mass spectrometric analysis. J. Chromatogr. A 1012, 207–214. Li, D., Oh, J.R., Park, J., 2004. Distribution characters of nonylphenol in the artificial Lake Shihwa, Korea and surrounding creeks. Chemosphere (in press). Manzano, M.A., Perales, J.A., Sales, D., Quiroga, J.M., 1999. The effect of temperature on the biodegradation of a
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nonylphenol polyethoxylate in river water. Water Res. 33, 2593–2600. Ministry of Environment Republic of Korea, 2002. Available at http://www.me.go.kr/. Naylor, C.G., 1995. Environmental fate and safety of nonylphenol ethoxylates. Text. Chem. Colorist 27, 29–33. Nice, H.E., Thorndyke, M.C., Morritt, D., Steele, S., Crane, M., 2000. Development of Crassostrea gigas larvae is affected by 4-nonylphenol. Mar. Pollut. Bull. 40, 491–496. Renner, R., 1997. European bans on surfactant trigger transatlantic debate. Environ. Sci. Technol. 31, 316A–320A. Sabik, H., Gagne, F., Blaise, C., Marcogliese, D.J., Jeannot, R., 2003. Occurrence of alkylphenol polyethoxylates in the St. Lawrence River and their bioconcentration by mussels (Elliptio complanata). Chemosphere 51, 349–356. Schwaiger, J., Mallow, U., Ferling, H., Knoerr, S., Braunbeck, Th., Kalbfus, W., Negele, R.D., 2002. How estrogenic is
nonylphenol?: A transgenerational study using rainbow trout (Oncorhynchus mykiss) as a test organism. Aquat. Toxicol. 59, 177–189. Staples, C.A., Williams, J.B., Blessing, R.L., Varineau, P.T., 1999. Measuring the biodegradability of nonylphenol ether carboxylates, octylphenol ether carboxylates, and nonylphenol. Chemosphere 38, 2029–2039. Tanghe, T., Devriese, G., Verstraete, W., 1998. Nonylphenol degradation in lab scale activated sludge units is temperature dependent. Water Res. 32, 2889–2896. Tsuda, T., Takino, A., Muraki, K., Harada, H., Kojima, M., 2001. Evaluation of 4-nonylphenols and 4-tert-octylphenol contamination of fish in rivers by laboratory accumulation and excretion experiments. Water Res. 35, 1786–1792. Yadetie, F., Male, R., 2002. Effects of 4-nonylphenol on gene expression of pituitary hormones in juvenile Atlantic salmon (Salmo salar). Aquat. Toxicol. 58, 113–129.
Seasonal flux of nonylphenol in Han River, Korea Donghao Li
a,*
, Minseon Kim a, Won Joon Shim a, Un Hyuk Yim a, Jae-Ryoung Oh a, Young-Jin Kwon b
a
b
South Sea Institute, Korea Ocean Research and Development Institute, Jangmok-myon 391, Geoje-shi, Gyungsangnamdo 656-834, South Korea Department of Environmental Science, Kangwon National University, 192-1 Hyoja-dong, Chunchon 200-701, South Korea Received 14 October 2003; received in revised form 7 January 2004; accepted 27 January 2004
Abstract In order to understand the behavior of nonylphenol (NP) in Han River, water, suspended particle and sediment samples were analyzed during summer, autumn and winter. Concentrations of nonylphenol in water ranged from 23.2 to 187.6 ng/l, in suspended particle from 6.8 to 190.8 ng/l and in sediment from 25.4 to 932.0 ng/g dry wt. An increasing trend in the concentration is noticed in all matrices along down the river. In case of water and suspended particle, concentrations were higher in warmer season than in colder season. Percentage of nonylphenol in the suspended particle phase decreased from 67% to 28% with decreasing temperature in water. A reasonable correlation (R2 ¼ 0:63) was obtained for water and suspended particle. The partition coefficient Log Kp is 4.8. No seasonal variation of the concentration in sediment is noticed in this study. Ó 2004 Elsevier Ltd. All rights reserved. Keywords: Alkylphenols (APs); Nonylphenol (NP); Endocrine disruptor chemical; River
1. Introduction Nonylphenol is an endocrine disruptor. It is a degradation product of alkylphenol polyethoxylates (APnEOs) that is used in the world as nonionic surfactant and detergent in industrial and domestic applications over the last five decades (Giger et al., 1984). Due to persistence in the environment, it is bioconcentrated in organisms. In fact, high levels of nonylphenol were found from seafood and fish caught in Italian coast and Japanese rivers, respectively (Ferrara et al., 2001; Tsuda et al., 2001). Although the APnEOs are less toxic to human and organisms, the degradation products such as nonylphenol is toxic with hormone like properties. Yadetie and Male (2002) and Hemmer et al. (2002) reported that
*
Corresponding author. Tel.: +82-55-639-8671; fax: +82-55639-8689. E-mail address: [email protected] (D. Li).
nonylphenol has adverse effect on fish hormone system even at low concentrations. In order to avoid any adverse toxic effect on humans and biota, many countries have banned or regulated recently the production and application of APnEOs (Renner, 1997; Isobe et al., 2001). Though APnEOs have been in use for several decades, research on nonylphenol that helps to regulate these chemicals is hardly found in Korea. As a result, high levels of nonylphenol were found in several river estuaries and lakes in Korea. For examples, we reported in a recent paper (Li et al., 2004) that the average concentration of nonylphenol in creek water was 3.6 lg/l. Khim et al. (1999) reported nonylphenol concentrations ranging from 20.2 to 1820 ng/g dry wt in Shihwa Lake sediments. However, there is no reported data in riverine system though most of APnEOs is disposed as surfactant and detergent, directly into aquatic systems such as rivers, lakes and seas via drainage. In fact, the rivers are the major transport media of alkylphenol pollutants in Korea.
0045-6535/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2004.01.034
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D. Li et al. / Chemosphere 56 (2004) 1–6
Han River is the longest and biggest in Korea. It flows over a distance of 482 km, with an area of 26 000 km2 . The average depth of the river in the center is about 6 m. It supplies drinking water to over twenty millions people living around the river. Among them, twelve millions live in Seoul City. Several sub-streams of Han River pass through the city. As a result, this river accumulates large amount of wastewater and sewage from Seoul. It is doubtful that the Seoul wastewater facility removes these compounds before allowing the drainage to the river (on the contrary, the warm water condition in the facility promotes degradation of APnEOs to nonylphenol). The chemical burden of nonylphenol increases tremendously during monsoon season with heavy floods when wastewater is discharged directly into the river. The capacity of the plant is insufficient to treat the large volume of waste water produced during the rainy seasons. According to Korean Environmental Ministry report in 2001, the COD and BOD ranged from 3.8 to 59.4 and from 0.8 to 19.7 mg/kg, respectively, and the suspended particle in the river ranged from 4.4 to 20.0 mg/l (Ministry of Environment Republic of Korea, 2002). In order to understand quantitatively the distribution and behavioral characteristics of phenolic compounds in the Han River environment, nonylphenol was determined from water, suspended particle and sediment samples in this study. Modeling of nonylphenol in the Han River environment is essential for regulation of these compounds in the Korean environment. One such modeling study was carried out in our laboratory and in Seoul University recently.
2. Materials and methods 2.1. Solvents and standards All organic solvents including acetone, dichloromethane and hexane were of pesticide grade and were purchased from Caledon (Canada). Nonylphenol, silylation reagent BSTFA (N,O-bis(trimethylsilyl) trifluoroacetamide), surrogate standard (bisphenol A-d14), gas chromatography internal standards (GCIS) including naphthalene-d8, phenanthrene-d10 and pyrene-d10 were obtained form Chem Service (USA). The purity of all standards was up to 98%. HCl was purchased from Merck. Florisil was obtained from Supelco. In order to remove contaminants, the Florisil, Glass Fiber Filter and aluminum foil were burned at 450 °C for 12 h, then Florisil was activated at 120 °C until used and Glass Fiber Filter and aluminum foil were stored in vacuum desiccator. The copper was obtained from Merck, it was used to remove sulfur from the environmental sample extract after activating with concentrated HCl. All standards were prepared at 100 mg/l as a stock solution
with hexane acetone mixture (1:1). It was diluted approximately to calibration standards, surrogate standard (2 mg/l) and gas chromatography internal standard (GCIS) (2 mg/l) with acetone. 2.2. Sampling sites and sample collection In order to understand spatial distribution of nonylphenol in overall Han River, sediment samples were collected from ten sites in Aug. 2001 as shown in Fig. 1. Among them, site CC, CP, YZ, YP and PD were located in upstream, site KP, TY and KH were located in downstream, site KN and MW were located in the Seoul City vicinity. In order to study seasonal flux of nonylphenol in Han River, the study focused on KN and MW, and the sites were divided into five stations, respectively. Water, suspended particle and sediment samples were collected seasonally at these sites. The average water temperature in Aug., Oct. and Dec. were 27, 19 and 5 °C, respectively. One liter of filtered water sample (0.45 lm) was collected in 1 l glass bottle with Teflon lined cap. It was acidified to 0.01 M with 6 M HCl in order to protect it from biodegradation and to increase the stability of target phenolic analytes. The water samples were analyzed within 3 days. The filtered suspended particle matrix were wrapped with aluminum foil and stored in a glass bottle at )20 °C until analyzed. The surface sediment samples were sampled with van Veen Grap, then collected in glass bottle with Teflon lined cap and stored at about )20 °C until analysis. 2.3. Extraction and analysis Water, suspended particle and sediment samples were treated according to methods reported by Li et al. (2001, 2003). The brief analytical procedures were as follows. Acidified water samples were extracted using liquid liquid extraction (LLE) with dichloromethane after addition of appropriate amount of surrogate internal standard. The extracts were concentrated to 2 ml with rotary evaporator at 35 °C and reduced pressure. It was concentrated again with a gentle flow of dry nitrogen following addition of acetone in order to carry out fast silyl derivatization. It was submitted to on column derivatization and Florisil cleanup. Six milliliters of hexane was used as eluent. The concentrated eluents were analyzed by gas chromatography (Shimadzu GC17A)–mass spectrometry (Shimadzu MS QP-5000) with selected ion monitoring mode after addition of 200 ng of GCIS. Conditions of GC/MS analysis were described in a previous report (Li et al., 2001). Wet suspended particle and 3 g of wet sediment samples were treated into a solid suspension by adding appropriate amount of 0.1 M HCl solution. It was digested for 10 min, and then extracted three times using shaking technique with three portions of 5 ml dichloromethane. The combined extract
D. Li et al. / Chemosphere 56 (2004) 1–6
3
Fig. 1. Location of sampling sites.
was concentrated to about 1 ml under a gentle dry nitrogen flow. In order to remove water and sulfur from the extract, anhydride sodium sulfate and copper were added sequentially into the extract. The extract was transferred into another glass vial that was cleaned previously with two rinsing of dichloromethane. It was concentrated again to 0.2 ml under a gentle flow of dry nitrogen, and then 1 ml of acetone was added to the concentrated extract. It was concentrated further to 0.5 ml. Following processes including derivatization, clean-up and concentration steps were same with in water sample treatment.
3. Results and discussion In Aug. 2001, sediment samples were collected in Han River, from upstream to downstream as indicated in Fig. 1. The results are shown in Fig. 2. Nonylphenol concentrations ranged from 46 to 256 ng/g dry wt. Levels
Concentration (ng/g dry wt.) of nonylphenol in sediment
250 200 150 100 50 0 CC
CP
YZ upstream
YP
PD
KN
MW
Seoul city
KP
TY
KH
Downstream
Sampling site along the river flow down
Fig. 2. Nonylphenol distribution in the sediment of the Han River.
of nonylphenol recorded in downstream river were generally higher than in the upstream. Though an increasing trend was noticed just downstream the city of Seoul, a dramatic increase in concentration was noticed in locations near Seoul City. This is up to five times, the concentration noticed elsewhere. This might be due to discharge of effluents containing large amount of sewage and wastewater from Seoul City. In order to understand seasonal distribution levels of nonylphenol in Han River, water, suspended particle and sediment samples were analyzed in Aug. (warmer), Oct. (medium), Dec. (colder) in 2001. As listed in Table 1, concentration levels of nonylphenol in water decreased with decreasing water temperature and in summer is generally two times higher. Usage of APnEOs in general and the activity of microorganism in the riverine system may play a role on the levels of nonylphenol. Among them, the amounts of APnEOs used are not likely to change during seasons and hence the seasonal variation of nonylphenol levels noticed in our study is principally due to microbial activity. Several papers reported that APnEOs have rapidly degraded into nonylphenol and shortened alkylphenol ethoxylates at high temperature, while the degradation rate becomes very slow at low temperature (Tanghe et al., 1998; Staples et al., 1999; Manzano et al., 1999). The concentration of nonylphenol showed not only seasonal flux but showed a spatial trend as well. Levels of nonylphenol increased in the downstream water in all seasons as shown in Table 1. For example, over 100 ng/l (except St 7) of nonylphenol were determined at the downstream site in Aug., while less than 85 ng/l (except St 5) of it was found at the upstream site in the same season. Ding et al. (1999) and Sabik et al. (2003) in the Lao-Jie and St. Lawrence River reported similar trends, respectively. The river after passing through the city gets
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Table 1 Concentrations of nonylphenol in water, suspended particle and sediment from Han River in 2001 Site St1 St2 St3 St4 St5 St6 St7 St8 St9 St10 b
Suspended particle (ng/l)
Sediment (ng/g dry wt)
Aug.
Oct.
Dec.
Aug.
Oct.
Dec.
Aug.
Oct.
Dec.
83.0 NAa 71.4 83.1 109.7 104.5 79.0 105.2 187.6 100.7
42.0 46.2 44.6 56.3 60.2 50.3 70.9 68.5 76.5 84.1
23.2 17.3 72.0 36.7 20.3 50.8 27.9 55.7 71.3 56.9
123.5(5.9)b 190.8(9.5) 115.9(3.8) NA 130.8(9.2) 151.0(8.9) 133.1(7.1) 109.6(9.5) 156.1(16.6) 160.1(7.9)
18.0(1.4) 26.0(1.1) 18.0(6.2) 22.0(9.3) 34.0(5.9) 28.0(1.9) 44.0(1.9) 48.0(3.1) 60.0(2.2) 56.0(3.3)
20.9(6.9) 6.8(1.6) 7.8(2.3) 17.1(4.3) 13.4(2.8) 20.4(4.2) 26.0(2.8) 14.4(1.0) 20.4(2.3) 23.0(2.6)
114.3 87.4 95.4 69.8 56.3 231.2 249.7 356.5 235.0 207.6
79.6 81.3 35.1 194.1 85.0 305.2 550.2 144.5 228.0 732.4
67.3 40.3 116.8 25.4 44.9 249.3 374.7 411.8 259.3 932.0
NA means not analyzed. Concentration (lg/g dry wt) was normalized by dry weight of suspended particle.
contaminated thus showing high levels along the downstream. Nonylphenol, the degradation product of APnEOs, is relatively hydrophobic compared with its parental compound that is readily water-soluble as detergents and surfactants. So nonylphenol is readily adsorbed on surfaces of suspended particle and sediment in aquatic systems, for a long period. Table 1 shows concentrations of nonylphenol in suspended particles that ranged from 1.0 to 6.9 in Dec., from 1.1 to 9.3 in Oct. and from 3.8 to 16.6 lg/g dry wt in Aug. The levels of nonylphenol in suspended particle varied by season and increased along the downstream water in all seasons except a few sites. High concentrations of nonylphenol were found in warmer season, and the concentrations reduced with decreasing water temperature resulting in low concentration in winter. Takada et al. has reported similar results in the investigation of nonylphenol from the Shiwada River, the average concentration of nonylphenol in suspended particle are 3.54 lg/g dry wt and the concentrations varied by season. As described above, the behavior of nonylphenol in water showed similar trend. It indicates that equilibrium of nonylphenol in water and suspended particle is reached rapidly and that primarily affect the concentration levels of nonylphenol in suspended particle. In such a case, reasonable correlation of nonylphenol in water and suspended particle is expected. Our results are presented in Fig. 3. In which, the partition coefficient was obtained as following: Log Kp ¼ Log Css dry wt=Cw : The Css and Cw are representing concentration of nonylphenol in suspended particle and in water, respectively. Calculated average of Log Kp is 4.8 with 13.5 of relative standard deviation. Since there is reasonable seasonal and spatial trend correlation of nonylphenol distribution profile in water and suspended particle, a
250
NP in suspended particle
a
Water (ng/l)
200 2
R = 0.63
150 100 50 0
0
50
100
150
200
NP in water
Fig. 3. Correlation of nonylphenol in water (ng/l) and suspended particle (ng/l).
reasonable correlation (R2 ¼ 0:63) was obtained. It clearly indicates that nonylphenol was readily absorbed to suspended particle in the Han River water system. In the Han River, over 60% of nonylphenol were found in suspended particle phase in Aug. as shown in Fig. 4. This decreased with decreasing temperatures in the winter. This could also be due to the fact that high particle concentrations are usually seen in the rainy season (Aug.) and low concentrations in the dry season (Dec.). The nonylphenol level in suspended particle in our study is two times higher than those reported by others. In the Tamagawa river and the Sumidagawa river in Japan, only about 20% of nonylphenol were found in the suspended particle due to effective removal of suspended particles during sewage treatment processes (Isobe et al., 2001). These contaminated suspended particles settle finally into the bottom of the river. It is reasonable to expect that large amount of nonylphenol is present in the sediment of the Han River as well. In fact high concentrations of nonylphenol were detected from the sediment. The nonylphenol ranged from 25.4 to 932.0 ng/g dry wt
Percentage (%) of nonylphenol
D. Li et al. / Chemosphere 56 (2004) 1–6
accumulation and persistence in the long term is not negligible. In order to protect humans and biota from the environmental effect of nonylphenol, selective removal of suspended particle from the Han River and restrictions on the usage and discharge of APnEOs are necessary.
100 suspended particle
80 60 40
water
Acknowledgements
20 0
5
Aug.
Oct.
Dec.
Sampling date
Fig. 4. Percentage of nonylphenol in water and suspended particle.
as shown in Table 1. Seasonal variation of nonylphenol as seen in water and particles are not seen with sediments (Figure not shown). The spatial distribution indicates an increasing trend in river sediment, downstream. This is at least three times higher downstream than those found in the upstream sampling sites. It indicates that most of the nonylphenol adsorbed by suspended particle during the river flow thorough the Seoul City settled finally to the bottom. The average partition coefficient (Log Kp ) calculated from the every site and season ranged from 2.7 to 4.2. There is no reasonable correlation between nonylphenol in sediment and water (R2 ¼ 0:02) (Figure not shown). This might be due to (1), flow rate of Han River is relatively fast, not allowing time for equilibrium partitioning (2), degradation rates of nonylphenol and its mother compound APnEOs in the water are significantly faster than those in sediment. (3), concentration of nonylphenol in water varied through seasons. Various factors such as temperature, flow rate, sedimentation rate, and particle size etc., may affect concentration of nonylphenol in sediment and water and a detailed study is needed to understand this fully. Although measured average concentrations of nonylphenol in water, suspended particle and sediment are much lower than reported acute toxicity levels, some individual values in suspended particle are nearly the same as that of reported toxic levels. Regulatory levels of nonylphenol in USA and Europe are 1 lg/l in water (Renner, 1997). Naylor (1995) reported that the lowest effective concentration of nonylphenol in shrimp for subacute toxicity is 26 ng/g dry wt in sediment. The threshold level of nonylphenol for fish vitellogenin stimulation is 1 lg/l (Schwaiger et al., 2002). Nice et al. (2000) also reported that the exposure of Pacific oyster larvae, Crassostrea gigas, to nonylphenol is as low as 0.1 lg/l causing delay in development and a significant decrease in survival rate. Based on those reports, levels of nonylphenol in suspended particle might be potentially hazardous to organisms in the river. In addition, the effect on humans and other aquatic organisms through
The authors are grateful to Dr. Narayanan Kannan for his valuable comments on our manuscripts. This study is a part of a project supported by National Institute of Environmental Research, Korea (Project No. PG333-00). We thank the captain and crews of boats in the Han River Management Office for helping the sample collection.
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