Marine Pollution Bulletin 88 (2014) 383–388

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Marine Pollution Bulletin

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Occurrence and fate of triclosan and triclocarban in a subtropical riverand its estuary

http://dx.doi.org/10.1016/j.marpolbul.2014.07.0650025-326X/� 2014 Elsevier Ltd. All rights reserved.

⇑ Corresponding author at: Institute of Urban Environment, Chinese Academy ofSciences, Xiamen 361021, China. Tel.: +86 592 6190768.

E-mail address: cpyu@iue.ac.cn (C.-P. Yu).1 First two authors made equal contributions.

Min Lv a,b,1, Qian Sun a,c,1, Haili Xu a,d, Lifeng Lin a, Meng Chen e, Chang-Ping Yu a,c,⇑a Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, Chinab University of Chinese Academy of Sciences, Beijing 100043, Chinac Ningbo Urban Environment Observation and Research Station-NUEORS, Chinese Academy of Sciences, Ningbo 351800, Chinad College of Chemical Engineering, HuaQiao University, Xiamen 361021, Chinae College of Environment and Ecology, Xiamen University, Xiamen 361005, China

a r t i c l e i n f o

Article history:Available online 16 September 2014

Keywords:TriclosanTriclocarbanOccurrenceMicrocosmRiverEstuary

a b s t r a c t

The occurrence of triclosan (TCS) and triclocarban (TCC) in a subtropical river (Jiulong River) and its estu-ary was investigated for two years. TCS and TCC were ubiquitously detected in the Jiulong River and itsestuary. The levels of TCS and TCC ranged from less than the method detection limit to 64 ng/L and from0.05 to 14.1 ng/L in the river, respectively. The levels of TCS and TCC in the estuary ranged from 2.56 to27.25 ng/L and 0.38 to 5.76 ng/L, respectively. Temporal and spatial variations of TCS and TCC in the Jiu-long River and its estuary were observed during the investigation. The weather conditions did not showsignificant correlations with TCS and TCC, whereas several water quality parameters showed high corre-lations with TCS and TCC. The microcosm studies showed that both direct photolysis and biodegradationcontributed to TCS removal, whereas indirect photolysis was important for TCC removal in the surfacewater.

� 2014 Elsevier Ltd. All rights reserved.

A decade ago, the United States Geological Survey (USGS)national reconnaissance of emerging contaminants surveyreported that 80% of the surveyed streams (approximately 108US streams) were contaminated with trace amounts of organiccompounds, including steroidal hormones, antimicrobial agents,stimulants, and many other pharmaceuticals and personal careproducts (PPCPs) (Kolpin et al., 2002). The detection of these vari-ous compounds has gained extensive public attention due to theirpotential adverse effects on ecological and public health. Twowidely used antimicrobial agents on the list, triclosan (TCS) and tri-clocarban (TCC), have received wide concern. TCS has been sug-gested to be potentially weakly androgenic (Foran et al., 2000),and TCC has been demonstrated to be an endocrine disruptor byacting as a steroidal hormone amplifier (Chen et al., 2008).

The widespread use of TCS and TCC-containing products hasreleased TCS and TCC into the receiving aquatic environment viatreated and untreated sewage due to the imperfect coverage ofsewage treatment facilities, particularly in developing countries.Many researchers have reported on their incomplete removal by

wastewater treatment plants (Singer et al., 2002; Sun et al.,2014). Therefore, it is necessary to investigate the occurrence ofTCS and TCC in the receiving aquatic environment. To date, TCSand TCC have been detected in the aqueous environment of variouscountries, including the United States (Yu and Chu, 2009), Canada(Hua et al., 2005), United Kingdom (Sabaliunas et al., 2003),Switzerland (Lindstrom et al., 2002) and China (Zhao et al., 2010;Wang et al., 2011, 2012). However, few studies have monitoredTCS and TCC in the surface water over an extended period oftime, and information about the factors influencing theiroccurrence and fate is limited.

Natural attenuation, a combination of naturally occurring pro-cesses, can reduce concentrations of pollutants during river flow(Gurr and Reinhard, 2006). The possible mechanisms of naturalattenuation that could attenuate TCS and TCC in the river includedilution due to wastewater discharges or dilution due to rainfall,sorption, photolysis and biodegradation. Sorption seems to beimportant for both TCS and TCC due to their high lg Kow(Loftsson et al., 2005; Heidler et al., 2006), and sediment wasreported to be a sink for TCS and TCC (Zhao et al., 2010). Tixieret al. (2002) combined laboratory studies, field measurementsand modeling and concluded that direct photodegradationaccounted for 80% of the observed total elimination of TCS in thewater column of a Swiss lake. As for biodegradation, although

384 M. Lv et al. / Marine Pollution Bulletin 88 (2014) 383–388

microbial transformation of TCS and TCC were reported (Roh et al.,2009; Miller et al., 2010), information regarding the natural atten-uation of TCS and TCC through biodegradation in the surface wateris limited.

A two-year study of the occurrence of TCS and TCC in theJiulong River and its estuary was conducted to address the knowl-edge gap and to better understand the occurrence of and factorsaffecting the behavior of TCS and TCC in natural surface water.The Jiulong River is the second largest river in Fujian Province inthe southeastern part of China. The study explored the factors thatpotentially correlated with the occurrence of TCS and TCC, includ-ing weather conditions and water quality parameters. Further-more, the microcosm study was used to assess the existence andrelative importance of two attenuation mechanisms: photolysisand biodegradation of TCS and TCC in the surface water.

Six sampling sites were selected from both the North River (NR,N1-N6) and the West River (WR, W1-W6), the two major prongs ofthe Jiulong River (Fig. 1). Samples were collected on October21–22, 2011; March 27–28, 2012; September 5–6, 2012; January15–17, 2013; and June 7–9, 2013. Detailed information about theweather conditions, including rainfall, sunshine duration and tem-perature is provided in the Supporting Information (SI) Table S1.The Jiulong River Estuary is a typical subtropical estuary on thesouthwest coast of the Taiwan Strait. The surface water of the Jiu-long River Estuary was collected on September 8, 2012; January 16,2013; and June 9, 2013. The estuary water sampling sites (E1–E12)are described in Fig. 1. The salinities and pH are shown in Fig. S1.

For the TCS and TCC analysis, grab samples (1 L) were collectedfrom each site using amber glass bottles. All of the samples weretransported in ice-packed coolers to the laboratory and stored at

Fig. 1. Area maps and sampling sites in Jiulon

4 �C. Samples were processed within 24 h. Detailed informationabout the sample preparation and analytical methods of TCS andTCC in the present study is listed in SI. The SI includes samplingand analysis information for water quality parameters, includingpH; electronic conductivity (EC); dissolved oxygen (DO); watertemperature (Tem); salinity (SAL); ammonium (NH4

+); nitrate(NO3

�); nitrite (NO2�); phosphate (PO4

3�); total dissolved phospho-rus (TDP); and total dissolved carbon (TDC).

More than 10 L of surface water samples were collected fromN1, W2, and E8 on June 7–9, 2013 for the microcosm study. Themicrocosm study was set up in duplicate according to the previousstudy (Fono et al., 2006), with slight modifications. The first set ofexperiments (referred to as Dark surface water) investigated bio-degradation and used 1050 mL water samples in Pyrex Beakersthat were covered with aluminum foil. The second set of experi-ments (referred to as Light surface water) investigated the effectof the combined photolysis–biodegradation. These experimentsused 1050 mL water samples that were covered with quartz lids.The third set of experiments (referred to as Light killed surfacewater) investigated the effect of photolysis and used 1050 mLautoclaved water samples that were covered with quartz lids.The fourth set of experiments (referred to as Light Milli-Q water)investigated the effect of photolysis in Milli-Q water control. Theseexperiments used 1050 mL autoclaved Milli-Q water samples thatwere covered with quartz lids. The fifth set of experiments(referred to as Dark killed surface water) served as the kill controland used 1050 mL autoclaved water samples that were coveredwith aluminum foil. TCS and TCC were spiked into all of the beak-ers at an initial concentration of 2 lg/L. The beakers were placedon the roof of the Environmental Technology Building at the

g River and its estuary (Southeast China).

M. Lv et al. / Marine Pollution Bulletin 88 (2014) 383–388 385

Institute of Urban Environment under natural sunlight in June2013. Aliquots of 50 mL were sampled from all nine beakers at 0,4, 9, and 14 days using a pipette, acidified to pH 2.0 by hydrochloricacid, and added with 10 lL 13C12-TCS (10.00 mg/L) as internal stan-dards and concentrated and analyzed as discussed in SI.

The identification of TCS and TCC was performed by liquid chro-matography tandem mass spectrometry (LC-MS/MS) analysis withmultiple reaction monitoring (MRM) mode, using the 2 highestcharacteristic precursor ion/product ion transition pairs (Table S2).TCS and TCC were also identified using the LC retention time ±10%of the retention time of a standard. The standard calibrations werelinear over a concentration range of 1.0–500 ng/mL and 0.2–200 ng/mL for TCS and TCC, respectively. The method detection lim-its (MDLs) of TCS and TCC were 0.7 ng/L and 0.01 ng/L in surfacewater, respectively, and 5.0 ng/L and 0.1 ng/L in the microcosmstudy, respectively.

The internal standard (13C12-TCS) was applied for each samplefor quality control, and the recoveries of 13C12-TCS were 76–115%. In addition, a method blank, a spiked sample, and a sampleduplicate were applied in each batch. Neither TCS nor TCC weredetected in the method blank. The recoveries varied from 92.3%to 117% for TCS and 78.6% to 103% for TCC. The relative percentdifferences of TCS and TCC concentration between duplicate sam-ples were less than 30%.

A principal coordinate analysis (PCoA) was used to investigatethe factors influencing the occurrence of TCS and TCC. A one-wayanalysis of variance (ANOVA) was used to test the significantdifferences in the concentrations. A Pearson linear correlationanalysis was used to explore the possible relationships betweenwater quality parameters and TCS and TCC concentrations. All ofthe statistical analyses were conducted using SPSS 16.0.

The concentration ranges, median concentration and detectionfrequencies of TCS and TCC in the NR and WR of the Jiulong Riverare displayed in Fig. 2 and Table S3. TCS and TCC were both ubiq-uitously detected in the samples from the Jiulong River, with thedetection frequencies mostly up to 100%. The only exception wasthat the level of TCS in N3 in Oct 2011 was <MDL. In the JiulongRiver, the levels of TCS and TCC were in the range from <MDL to64 ng/L and from 0.05 to 14.1 ng/L, respectively, with the concen-tration of TCS several times to three orders of magnitude higherthan TCC. The higher concentration of TCS than TCC in surfacewater could also be found in surface water in the Pearl River sys-tem in Southern China (Zhao et al., 2013). This finding may reflectthe different consumption for these two compounds and the factthat TCC has a lower solubility and a higher lg Kow (Loftssonet al., 2005), which makes it liable to accumulate in sediment.

TCS concentrations in the surface waters of the Jiulong Riverwere comparable to those reported in the Yellow River (Wang

TC

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(ng/

L)

0

10

20

30

40

50

60

70A

A

A

B

B

Oct 2011 Mar 2012 Sep 2012 Jan 2013 Jun 2013

Fig. 2. Seasonal variations in the TCS (left) and TCC (right) concentrations in the Jiu

et al., 2012), Liao River (Wang et al., 2011), Liuxi River and ZhujiangRiver (Zhao et al., 2010) in China and rivers in Spain (Pedrouzoet al., 2009), Japan (Nishi et al., 2008), Switzerland (Lindstromet al., 2002; Singer et al., 2002), Germany (Bester, 2005) and Korea(Kim et al., 2007) (Table 1). However, higher TCS concentrationswere detected in the urban riverine water of Guangzhou (Penget al., 2008), Shijing River (Zhao et al., 2010) and streams in theUS (Kolpin et al., 2002) (Table 1). In contrast to TCS, few studiesreported the occurrence of TCC in the surface water. TCC concen-trations in the Ebro and Llobregat Rivers in Spain were below thelimit of quantification (LOQ) (20 ng/L) (Pedrouzo et al., 2009).The detected values of TCC in the Shijing River were found up to338 ng/L, with mean and median concentrations of 158 ng/L and145 ng/L (Zhao et al., 2010) (Table 1), which were much higherthan those found in the Jiulong River (Table S3).

The temporal variations of the concentrations of TCS and TCCwere observed in the Jiulong River (Fig. 2). We basically observedan increasing trend for both the concentrations of TCS and TCC overtime, except for the samples taken in June 2013. The increasingtrend might reflect the growing use of the antimicrobial agentsin the consumer products used in our daily lives (Huang et al.,2014). The lower concentrations of TCS and TCC in June 2013 mightbe due to the dilution effects caused by higher rainfall during thesampling month. The spatial variations of the concentrations ofTCS and TCC were also observed in the Jiulong River, and concen-trations of TCS and TCC tended to be higher close to the city(Fig. 3). For example, N1 (close to Longyan City) and W2 (close toHeping City) had relatively higher concentrations of TCS and TCC,which suggested that cities should be a major source of TCS andTCC in the receiving water.

The distribution of TCS and TCC in the Jiulong River Estuary isshown in Fig. 4. TCS and TCC in the surface water of the estuaryranged from 2.56 ng/L to 27.25 ng/L and 0.38 ng/L to 5.76 ng/L,respectively. As shown in Table 1, the TCS concentrations in theJiulong River Estuary were within the ranges reported in Tai PoHarbor in Hong Kong (Wu et al., 2007) and the Glatt River Estuaryin Switzerland (Lindstrom et al., 2002) but higher than those in theHudson River Estuary (Wilson et al., 2009) and Narragansett Bay inthe US (Sacks and Lohmann, 2011) and the Tagus River Estuary inPortugal (Neng and Nogueira, 2012). In contrast to TCS, limiteddata were available for TCC in estuaries and seawater. A previousstudy reported that TCC could not be detected in San FranciscoBay in the US (Klosterhaus et al., 2013) (Table 1).

Similar temporal variations of TCS and TCC were observed inthe estuary as in the river (data not shown), which suggested thatthe levels of TCS and TCC in the estuary were strongly impacted bythe input of NR and WR. In general, the concentrations of TCS andTCC showed a declining trend towards the sea, although there were

Oct 2011 Mar 2012 Sep 2012 Jan 2013 Jun 2013

TC

C c

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(ng

/L)

0

2

4

6

8

10

12

14

16

B

A

A

BB

long River (Different letters (A, B) represent significant differences at p < 0.05).

Table 1Summary of the ranges, mean and median concentrations of TCS and TCC in different areas (ng/L).

Country River TCS TCC Reference

Range Mean Median Range Mean Median

China Yellow River ND-49.9 6.8 4.2 / / / Wang et al. (2012)China Urban river of Guangzhou 35–1023 / 77–405 / / / Peng et al. (2008)China Liuxi River <LOQ–26.2 13.7 11.9 <LOQ-13.9 7.4 6.0 Zhao et al. (2010)China Zhujiang River 6.5–31.1 16.8 16.2 4.5–46.2 19.9 17.1 Zhao et al. (2010)China Shijing River 90.2–478 242 238 68.8–338 158 145 Zhao et al. (2010)China Liao River 6.5–81.3 28.4 / / / / Wang et al. (2011)China Tai Po Harbor 14.9–17.5 / / / / / Wu et al. (2007)China Victoria Harbor 29.8–109.9 / / / / / Wu et al. (2007)Japan Tone Canal 11–134 / / / / / Nishi et al. (2008)Korea Han River, Nakdong River ND / / / / / Kim et al. (2007)USA 139 Streams in USA ND-2300 / 140 / / / Kolpin et al. (2002)USA Mississippi River 8.8–34.9 / / / / / Zhang et al. (2007)USA Urban streams in USA / / / ND-5600 / / Halden and Paull (2004)USA Hudson River Estuary 1–3 1.67 1 / / / Wilson et al. (2009)USA Narragansett Bay ND / / / / / Sacks and Lohmann (2011)USA San Francisco Bay / / / ND / / Klosterhaus et al. (2013)Canada/USA Detroit River <4–8 / / / / / Hua et al. (2005)Switzerland Glatt River 11–74 / / / / / Lindstrom et al. (2002)Switzerland Rivers in the country 11–98 / / / / / Singer et al. (2002)Spain Ebro and Llobregat Rivers <LOQ / / <LOQ / / Pedrouzo et al. (2009)Portugal Estuary and seawater <5 / / / / / Neng and Nogueira (2012)Germany Ruhr River <3–10 / / / / / Bester (2005)Germany Seawater 0.001–6.87 / / / / / Xie et al. (2008)

‘‘ND’’: not detected, ‘‘<LOD’’: below the limits of detection, ‘‘/’’: no available data.

Sites

TC

S co

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(ng/

L)

0

10

20

30

40

50

60

70

Sites

N1 N2 N3 N4 N5 N6 W1 W2 W3 W4 W5 W6 N1 N2 N3 N4 N5 N6 W1 W2 W3 W4 W5 W6

TC

C c

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tion

(ng

/L)

0

2

4

6

8

10

12

14

16

Fig. 3. The distribution of TCS and TCC in the Jiulong River. The solid and dotted lines in the box represent the median and mean concentrations, respectively.

Sites

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L)

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5

10

15

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25

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Sites

E1 E2 E3 E4 E5 E6 E7 E8 E9 E10 E11 E12 E1 E2 E3 E4 E5 E6 E7 E8 E9 E10 E11 E12

TC

C c

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tion

(ng

/L)

0

1

2

3

4

5

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7

Fig. 4. The distribution of TCS and TCC in the Jiulong River estuary. The solid and dotted lines in the box represent the median and mean concentrations, respectively.

386 M. Lv et al. / Marine Pollution Bulletin 88 (2014) 383–388

PC1 (41.9%)

-1.0 -.8 -.6 -.4 -.2 0.0 .2 .4 .6 .8 1.0 1.2

PC

2 (2

2.3%

)

-1.0

-.8

-.6

-.4

-.2

0.0

.2

.4

.6

.8

1.0

TCCTCS

pH

Tem

DOSAL

TDC

NO2- NO3-

NH4+

TDP

PO43-

Fig. 5. PCoA analysis of the TCS and TCC concentrations and water qualityparameters in the Jiulong River estuary.

Table 2The average first-order rate constants (day�1) for the degradation of TCS and TCC inmicrocosms.

N1 W2 E8

TCS TCC TCS TCC TCS TCC

Light Milli-Q water 0.23 0.05 0.23 0.04 0.21 0.04Light surface water 0.31 0.22 0.35 0.27 0.16 0.07Light killed surface water 0.17 0.13 0.21 0.20 0.17 0.07Dark surface water 0.14 0.06 0.13 0.05 0.02 0.005Dark killed surface water 0.03 0.03 �0.01 0.06 0.01 0.004

M. Lv et al. / Marine Pollution Bulletin 88 (2014) 383–388 387

some exceptions (Fig. 4). There was a distinguishable decliningtrend of TCS concentrations from E6 to E8, which was likely dueto the huge dilution of seawater from E6 to E8 because there wasa sharp increase of SAL from E6 to E8 (Fig. S1). A similar trendwas observed in the German Bight (Xie et al., 2008). However,there was an increasing trend from E9 to E11, which was likelydue to the discharges of the effluent from the waste water treat-ment plants P1 and P2 in Xiamen City (Fig. 1).

The Pearson linear correlation analysis was used to investigatethe relationships of the weather conditions (rainfall, temperature,sunshine duration) with the occurrence of TCS and TCC in the Jiu-long River, but no significant correlation was observed. The PCoAanalysis was conducted and showed that the average concentra-tions of TCS and TCC correlated distantly with weather conditions(Fig. S2), suggesting that the occurrence of TCS and TCC was notdetermined solely by these weather conditions. However, the tem-perature and sunshine duration were closer to TCS than to TCC,indicating that they had a stronger influence on TCS than TCC.

The Pearson linear correlation analysis was also used to explorethe correlation between water quality parameters and the concen-trations of TCS and TCC in the Jiulong River and its estuary(Table S4). We found that the concentration of TCS was positivelycorrelated with pH and TDC but negatively correlated with DO, ECand TDP (p < 0.05). The concentration of TCC was positively corre-lated with NH4

+ but negatively correlated with pH, EC and water tem-perature (p < 0.05). Interestingly, no significant correlation wasfound between the TCS and TCC concentrations in the Jiulong River.This finding could also be reflected in the fact that TCS and TCC weregenerally correlated with different water quality parameters.

We found that the pH values were positively correlated with TCSconcentrations but negatively correlated with TCC concentrations(Fig. S3). This finding was consistent with a previous report thatthe sorption of TCS to the particulate organic carbon was pH depen-dent and that the dissolved state of TCS increased from 40% to 91%when increasing pH 6 to pH 9 (Young et al., 2008). Considering thelong-term accumulation of TCS in the sediment because of its highlg Kow (Loftsson et al., 2005), the positive correlation between pHand TCS, to some extent, indicated that the TCS concentration waslikely influenced by the adsorption–desorption process in thenatural aquatic system. However, not only was the sorption ofTCC influenced by pH values (Young et al., 2008), but the photodeg-radation rate of TCC also increased with pH (Ding et al., 2013).Photodegradation proved to be the important attenuation mecha-nism for TCC in this study, as shown in the microcosm studies.Therefore, the negative correlation between TCC and pH indicatedthat pH likely influenced TCC occurrence by influencing its photo-degradation in surface water.

For the estuary, we found that the TCS concentration was posi-tively correlated with TDC, NO2

�, NO3�, NH4

+ and PO43� but negatively

correlated with water temperature (p < 0.05). The concentration ofTCC was positively correlated with DO, NO3

�, NH4+ and PO4

3� butnegatively correlated with pH, SAL and water temperature(p < 0.05). The PCoA analysis was conducted to examine the possi-ble impact of seawater dilution on TCS, TCC and the water qualityparameters (Fig. 5). The results for the PCoA analysis in the estuarydiffered from those in the Jiulong River (Fig. S4). TCS, TCC and sev-eral other wastewater quality parameters were clustered togetherand were distant from SAL. The results of the Pearson linear corre-lation analysis and PCoA analysis were consistent. The resultsimplied the potential impact of sewage discharge and seawaterdilution on the occurrence of TCS and TCC in the estuary.

The microcosm experiments were designed to enhance ourunderstanding of the biodegradation and photolysis of TCS andTCC in the Jiulong River and its estuary. We selected samples fromN1 and W2 because the TCS and TCC concentrations were generallyhigher in these two sites (Fig. 3), whereas the sample from E8 was

selected to reflect the impact of sea water (Fig. S1). The first-orderrate constants for the degradation of TCS and TCC in microcosmsare summarized in Table 2.

The comparison of the degradation rates of TCS in the LightMilli-Q water and the Light killed surface water implied that directphotolysis was the dominant photolysis mechanism for TCSremoval (Fono et al., 2006) and that indirect photolysis seemednegligible. The higher degradation rates in the Dark surface watercompared with the Dark killed surface water for TCS in both N1and W2 indicated that biodegradation played an important partin the degradation processes of TCS. The reason for the low biodeg-radation rate of TCS in E8 was likely because the seawater dilutionreduced the potential TCS-degrading bacteria in the estuary water.The differences in the degradation rates for the Light surface waterand the Light killed surface water in N1, W2 and E8 further indi-cated that photolysis could be the essential attenuation mecha-nism for TCS in the Jiulong River and estuary area. The resultswere in accordance with a former study in a Swiss lake (Tixieret al., 2002). That study found that direct phototransformationaccounted for most of the observed elimination of TCS from thelake.

In comparison with TCS, the results were different for TCC(Table 2). There was a large difference in the degradation ratesbetween the Light Milli-Q water and the Light killed surface waterfor both N1 and W2. Therefore, indirect photolysis was consideredthe dominant photolysis mechanism for TCC in the surface water.The low photolysis rates of TCC in E8 were likely due to the lackof a photosensitizer, such as dissolved organic matter and nitrate,because the photosensitizer could act as a light absorber and wasindispensable in indirect photolysis (Ryan et al., 2011). The com-parison of the TCC degradation rates in the Dark surface waterand the Dark killed surface water implied that biodegradation con-tributed only slightly to TCC removal. However, the higher TCCdegradation rates in the Light surface water compared with thoseof the Light killed surface water in both N1 and W2 revealed thatthe synergistic effect of microorganisms and sunlight significantly

388 M. Lv et al. / Marine Pollution Bulletin 88 (2014) 383–388

enhanced TCC degradation. A previous study demonstrated thatphototrophic bacteria could degrade aromatic compounds(Harwood and Gibson, 1988; Zhao et al., 2011), and furtherresearch is necessary to clarify whether the enhanced degradationof TCC is due to the biodegradation by phototrophic bacteria.

The correlation analysis indicated a stronger influence of tem-perature and sunshine duration on TCS than TCC (Fig. S2), whichcould be explained by the microcosm results. A more significantbiodegradation was observed in the microcosm studies for TCSthan TCC, and temperature could impact microbial activity. There-fore, temperature had more of an influence on the removal of TCSthan on TCC. In addition, direct photolysis played an importantpart in the photodegradation of TCS, but indirect photolysis wasthe primary contributor to the photodegradation of TCC in theriver. Therefore, sunlight duration may have a higher correlationto TCS than to TCC.

Acknowledgements

We appreciate Dr. Anyi Hu and Mr. Jiangwei Li for the samplecollections. This work was supported by the National NaturalScience Foundation of China (NSFC41201490), Science andTechnology Planning Project of Xiamen, China (3502Z20120012),and Science and Technology Planning Project of Ningbo, China(2012C5011, 2013A610172).

Appendix A. Supplementary material

Supplementary data associated with this article can be found, inthe online version, at http://dx.doi.org/10.1016/j.marpolbul.2014.07.065.

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