Chemosphere 99 (2014) 109–116

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Target and screening analysis of 940 micro-pollutants in sediments in Tokyo Bay, Japan Shuangye Pan a,b, Kiwao Kadokami a,⇑, Xuehua Li c, Hanh Thi Duong a, Toshihiro Horiguchi d a

Faculty of Environmental Engineering, The University of Kitakyushu, 1-1 Hibikino, Wakamatsu, Kitakyushu, Fukuoka 808-0135, Japan Environment Monitoring Center of Ningbo,105 Baoshan Street, Ningbo 315012, China c Department of Environmental Science and Technology, Dalian University of Technology, Linggong Road, Dalian 116024, China d National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan b

h i g h l i g h t s

g r a p h i c a l a b s t r a c t

 A combination of target and screening

method was applied to sediments in Tokyo Bay.  195 Out of 940 organic chemicals were found.  Tokyo Bay was polluted with mainly domestic chemicals and fecal sterols.  PCBs and some OCPs had concentrations higher than the sediment quality guidelines.  This combination of target and screening method is useful for environmental surveys.

a r t i c l e

i n f o

Article history: Received 18 July 2013 Received in revised form 3 October 2013 Accepted 8 October 2013 Available online 9 November 2013 Keywords: Comprehensive analysis Chemical substances AIQS-DB POPs PAHs Fecal sterol

a b s t r a c t Urban societies are using an increasingly diverse array of chemicals, many of which ultimately end up accumulating in urban harbors, where they can act as contaminants alone or as part of a mixture. In attempt to grasp a more complete picture of anthropogenic chemicals in an urban harbor, we analyzed 940 organic chemicals in sediments in Tokyo Bay, one of the most densely populated and modernized areas in the world. For the chemical analysis, we used targeted analytical methods using a GC–MS–MS and a GC–MS–SIM, and a screening analysis using an automated identification and quantification system with a GC–MS database. We detected 195 organic chemicals in the sediments; the sum of concentrations of compounds detected varied from 6095 to 39 140 lg kg1 dry wt. Since their concentrations increased with proximity to the innermost part of the bay, their sources seem to be mainly sewage treatment plants (STPs) and rivers flowing to this area. Additional confirmation comes from the nature of the identified pollutants, which are characteristic of chemicals used in households as well as fecal matter, business activities and urban run-off. From these results, it was confirmed that sediments in Tokyo Bay are still polluted with a wide range of chemicals, particularly domestic chemicals, despite nearly 100% of wastewater from household and business activities being treated by STPs. Ó 2013 Elsevier Ltd. All rights reserved.

1. Introduction Tokyo Bay is located in one of the most densely populated, industrialized and modernized areas in the world. The bay is an ⇑ Corresponding author. Tel.: +81 93 695 3739; fax: +81 93 695 3787. E-mail address: [email protected] (K. Kadokami). 0045-6535/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.chemosphere.2013.10.038

almost entirely enclosed sea surrounded by three prefectures including Tokyo, the capital of Japan; nearly 30 millions of people live there. In addition to the vast population, a lot of factories are located in the coast of the bay including heavy industries; the

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industrial output of the industrial zone amounts to 20–30% of that of Japan. Tokyo Bay receives a vast volume of wastewater from domestic sources, industrial activities and also agricultural activities. Agriculture in suburban areas of Tokyo is mainly directed towards growing vegetables. Although almost all the wastewater from households, business activities and industry are treated by wastewater treatment plants, large amounts of man-made chemicals still flow into the bay. Many contamination assessments have been carried out in Tokyo Bay, including for polycyclic aromatic hydrocarbon (PAHs) (Zakaria et al., 2002), dioxins (Hosomi et al., 2003), polychlorinated biphenyls (PCBs) (Kobayashi et al., 2010), brominated flame reterdants (Minh et al., 2007), alkylphenols (Isobe et al., 2001), and perfluorinated compounds (Sakurai et al., 2010). But existing studies on chemicals have focused on a small numbers of target substances or a group of substances. It is therefore difficult to obtain a complete picture of chemical pollution of the bay. We have developed a screening method for 940 semi-volatile organic chemicals in sediments (Kadokami et al., 2012). Since we can obtain concentrations of a wide-variety substances using this method, it is possible to interpret the source activities of pollution (domestic, business, industrial and agricultural activities), the occurrence and sources of major pollutants, and the occurrence of specific substances and their spatial distribution. If we were to analyze the same large number of substances by targeted analytical methods, we have to do many tests at great cost and effort. Recently, we applied the method to sediments in Dokai Bay, a typical enclosed sea in Japan (Kadokami et al., 2013). In that study, we were able to characterize the pollution status of the bay, including identifying the main pollutants and their spatial pattern and sources. From these results, it was confirmed that the screening method is very useful way to grasp an overview of sediment contamination from which we can obtain further useful information regarding chemical pollution that cannot be obtained easily by conventional target analysis. In other words, we ‘‘see the forest’’ not ‘‘each tree’’ when using this screening analysis; if we detect some important substances using the screening method, we then examine them in more detail using targeted analysis. In Japan, more than 50 000 chemicals are used (ROE, 2009), and almost all of the substances are likely to be used in the Tokyo metropolitan area, making Tokyo Bay a good model for chemical pollution of modern society. Recently, it was reported that the sediment quality of Tokyo Bay is not suitable for benthic animals, particularly in the western coastal zone and the innermost part of the bay (Tokenshi Kankyo, 2013). The broad aim of the present study was to grasp a more holistic picture of the pollution of sediments in Tokyo Bay than has been achieved before as a model for that of developed nations. The specific objectives of the study were (1) to screen Tokyo Bay sediments for more than 940 semi-volatile organic chemicals using our GC–MS-database screening method, (2) to identify the contribution ratios made by human activities around the Bay, (3) to identify characteristic substances and their sources, and (4) to identify substances that cause adverse effects on benthic animals by comparing results to sediment quality guidelines. We did not aim to find emission sources of individual chemicals and their contributions to each sampling site because we did not have detailed data of emission sources located around Tokyo Bay. We utilized screening analysis of 940 substances followed by targeted analysis to accomplish the goals.

west: to the north the coast connecting Futtsu and Kannonzaki (Fig. 1). It is a semi-closed bay with a surface area of 960 km2, an average water depth of 15 m (Kasuya et al., 2004), and an average water residence time is 1.6 months (Matsumoto, 1989). Its catchment area is 9261 km2, or only 2% of the gross area of Japan, but the population of the catchment is 29 million or 23% of the total population of Japan. A large number of municipal and industrial facilities are located in the coast of the bay, including 27 sewage treatment plants (STPs), 21 municipal incinerators, 5 landfills, 3 ironworks, 8 oil refineries, 14 thermal power plants, and 3 dockyards (TBEIC, 2013). Fresh water from rivers flows into the bay at a rate of approximately 10 km3 y1; the Edo River, Ara River, and Tama River contribute about 90% of the freshwater entering into the bay (Managaki et al., 2006). These rivers flow through densely populated and industrial areas before inflow to the bay. Sediments were collected from 20 sites in Tokyo Bay (Fig. 1) on August 2009 using a Smith-Mcintyre bottom sampler; 19 samples, except for Stn 15 which contained a lot of sea shells, were analyzed. The top 5 cm of sediment was used for chemical analyses. The average sedimentation rates in Tokyo Bay are 0.18 g cm2 y1 (Matsumoto, 1983) and 0.2–0.3 g cm2 y1 (1.19–1.89 cm y1) (Hosomi et al., 2003). Based on these data, our samples correspond to accumulation in the last 3–5 years if no disturbance has occurred.

2.2. Target and screening analysis for 940 organic substances in sediment samples The analytical processes for the 940 semi-volatile organic substances (Table S1) were performed according to Kadokami et al. (2012). In short, a sample (10 g wet wt) spiked with surrogates (Table S2) was mixed with Hydromatrix (Varian, Palo Alto, CA, USA), and then was extracted with dichloromethane/acetone (1:1) using an accelerated solvent extractor (ASE 350; Japan Dionex, Osaka, Japan). Thereafter, the extract was concentrated using a rotary evaporator, and then was added to sodium chloride solution. The solution was extracted with dichloromethane twice and then dehydrated. Thereafter, the solvent was changed from dichloromethane to hexane. The hexane solution was

2. Materials and methods 2.1. Description of Tokyo Bay and collection of sediments Tokyo Bay is located in the southeast of the Tokyo Metropolis (Fig. 1). It is surrounded by the Boso Peninsula (Chiba Prefecture) to the east and the Miura Peninsula (Kanagawa Prefecture) to the

Fig. 1. Sampling location.

S. Pan et al. / Chemosphere 99 (2014) 109–116

concentrated, and was applied to a silica-gel cartridge (Sep-Pak VAC 2 g/12 mL; Waters Associates, Milford, MA, USA) and separated into 3 fractions: hexane (Fraction 1), 5% acetone-hexane (Fraction 2), and 30% acetone-hexane (Fraction 3). Fraction 1 was treated with copper powder (reduced copper, granular, super grade; Kishida Chemical, Tokyo, Japan) to remove sulfur. Fraction 3 was passed through an activated carbon column (ENVI-carb; Supelco, Bellefonte, PA, USA) to remove colored substances (e.g. non-volatile pigments) that damage a GC column. After adding internal standards to each fraction, we measured them with two instruments: GC–MS–SIM/Scan (QP-2100 Plus, Shimadzu, Kyoto, Japan) and GC–MS–MS–SRM (TSQ Quantum XLS, Thermo Fisher Scientific, Yokohama, Japan). Measurement conditions for both instruments are shown in Tables S3 and S4. Total ion current chromatograms obtained by a GC–MS-Scan were treated with an identification and quantification system with a GC–MS database (AIQS-DB) (Kadokami et al., 2005), that can determine the concentrations of the 940 semi-volatile organic compounds (Table S1). Target substances by SIM and SRM are listed in Table S3 and S4, respectively. The method detection limits (MDL) for the substances were estimated from concentration ratio (or, ratio of the dry weight of a sample to the volume of a final concentrate), and the instrument detection limit (IDL) (Table S1). For 84% of the chemicals in the database, the MDL was 62 lg kg1 dry wt. The MDL of the substances measured by SIM or SRM was 60.2 lg kg1 dry wt and 60.02 lg kg1 dry wt, respectively.

2.3. Analysis of total organic carbon Total organic carbon (TOC) in the sediments was measured by an elemental analyzer (NA-1500; Fisons Instruments, Dearborn, MI, USA) and expressed as a percentage of sediment dry weight. The amount of moisture in the sediments was determined by measuring weight loss after oven-drying 10 g of subsamples at 105 °C for 2 h.

2.4. Quality control The 940 substances screened in the sediment samples have a broad range of physico-chemical properties. To confirm the accuracy and precision of the method, recovery tests were conducted using 119 model compounds, which covered the same broad range of physico-chemical characteristics to the 940 chemicals in the screening method, including non-polar to polar compounds, and volatile to less volatile chemicals. As a result, it was confirmed that the method can quantitatively analyze most substances, except for very polar substances (Kadokami et al., 2012). During sample analysis, the analytical method was validated using a performance-based approach that included analysis of procedural blanks and certified reference materials (NIST 1941b (Organics in Marine Sediment; National Institute of Standards and Technology, Gaithersburg, MD, USA). In addition, recoveries of surrogates (Table S2), consisting of 38 substances with broad physico-chemical properties, were spiked into the samples to ascertain whether each analysis is correct or not.

2.5. Statistical analyses The statistical analysis was performed using Microsoft Excel 2010 (Microsoft Japan, Tokyo, Japan) and IBM SPSS Statistics Ver. 20 (IBM Japan, Tokyo, Japan).

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3. Results and discussion 3.1. Results of quality assurance and quality control The analytical results of the standard reference material NIST 1941b are shown in Table S5, which shows that although accuracy of the comprehensive method may be slightly lower than that of the conventional methods, it is sufficient for environmental surveys. Surrogate recovery tests were undertaken to confirm analytical performance of all the samples. Their recoveries (Table S2) are almost the same as those of the previous report (Kadokami et al., 2012). Analytical results were obtained by the subtraction of procedure blanks from values obtained by instrumental analysis. If samples were measured by multiple methods (Scan, SIM and/or SRM), we preferentially used results by SRM, next by SIM and lastly by Scan. 3.2. Overview of survey results of organic micro-pollutants The number of chemicals detected at each site increased towards the innermost part of the bay, from 142 individual substances at Stn 19 to 177 individual substances at Stn 7 (Table 1). A total of 195 substances were detected at least once, belonging to 25 different chemical groups (Table 1; Table S6). Substances indicative of pollution in the bay were sterols and domestic substances that appear to be discharged from STPs and rivers (Table 1 and S6). In addition to the number of chemicals, concentrations also increase towards the innermost part of the bay (Tables 1 and S1). The highest total concentration of chemicals (39 140 lg kg1 dry wt) was found at Stn 4 located in a coastal zone near Tokyo. Many chemicals are detected throughout the bay, such as antioxidants, fragrances, cosmetics, plasticisers, alkyl phenols, PAHs, organochlorine pesticides (OCPs) and many more (Table 1 and S6), indicating they enter from multiple sources like rivers, STPs and atmospheric deposition. However, the number and concentrations of industrial chemicals were much lower than those in Dokai Bay (Kadokami et al., 2013). 3.3. Chemical concentrations normalized to TOC Hydrophobic organic substances absorb to organic matter (Toro et al., 2005), and their concentrations are commonly assumed to be proportional with TOC in sediments. In the present study, significant positive correlations (r2 = 0.73) were observed between TOC and the detected substances (Fig. S2). The concentrations of TOC increased towards the innermost part of the bay (Table 2), and when normalized to TOC, the ratio of the total concentrations between maximum site and minimum site reduces to 3.0 (compared to 6.4 before normalization). 3.4. Sources and spatial distribution of sterols Sterols had the highest concentration compared to the other types of contaminants (Table 1). Coprostanol, which is an indicator of fecal pollution (Murtaugh and Bunch, 1967), increased in concentration towards the innermost part of the bay (Table S6), although the average concentration of the 19 sites was 68% of the concentration in 1970 (Ogura, 1983) when the sewerage coverage ratio in Tokyo was 48%. The ratio of copostanol to cholesterol (sterol ratio) can be used to indicate sewage contamination (>0.2) (Grimalt et al., 1990). In this study, the sterol ratio increased towards the innermost part

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Table 1 Sediment concentrations (lg kg-1 dry wt) and number of chemicals belonging to different chemical categories and origins at the 19 sampling sites in Tokyo Bay. Category/number

Stn 1

Stn 2

Stn 3

Stn 4

Stn 5

Stn 6

Stn 7

Stn 8

Stn 9

Stn 10 Stn 11 Stn 12 Stn 13 Stn 14 Stn 16 Stn 17 Stn 18 Stn 19 Stn 20

Agriculture

Insecticides 187 Herbicides 117 Fungicides 112 Other pesticides 36

5.1 10 0.30 1 – 0 – 0

384 6 0 0 – 0 – 0

5.8 10 0 0 – 0 – 0

6.0 10 0 0 – 0 – 0

3.9 8 0 0 – 0 – 0

4.3 8 0 0 – 0 – 0

7.2 10 0 0 – 0 – 0

4.2 7 0 0 – 0 – 0

3.8 9 0 0 – 0 – 0

2.0 4 0 0 – 0 – 0

2.9 8 0 0 – 0 – 0

3.7 9 0 0 – 0 – 0

1.6 4 0 0 – 0 – 0

1.8 7 0 0 – 0 – 0

0.54 4 0 0 – 0 – 0

1.8 12 0 0 – 0 – 0

0.55 4 0 0 – 0 – 0

0.16 4 0 0 – 0 – 0

0.35 4 0 0 – 0 – 0

Business/household/traffic Antioxidants 8 PPCPs 19 Cosmetics and fragrances 13 Disinfectants and insecticidal fumigants 2 Plasticizers 14 Metabolites of deterdants 3 Fire retardants 13 Compounds leached from tires 21 Fatty acid methy esters 34 Petroleum 26 Intermediates for resins 2 Other substances of domestic origin 27

663 3 349 2 52 6 5.3 1 816 6 125 1 36 3 71 3 14 2 4126 25 5.3 1 – 0

613 3 144 2 41 6 6.1 1 634 6 203 1 22 2 83 5 21 1 3733 25 14 1 – 0

1019 3 394 2 103 6 11 1 1169 6 139 1 47 2 139 3 24 1 7982 25 22 1 – 0

1391 3 958 2 138 5 14 1 5680 7 25 1 26 2 385 4 39 1 9272 25 2.6 1 – 0

813 3 639 2 94 7 25 1 1437 7 230 1 47 2 145 5 30 2 7513 25 21 1 – 0

904 3 1474 2 105 7 18 1 2849 7 105 1 52 3 227 6 154 2 8634 25 8.8 1 – 0

1221 3 278 2 64 7 17 1 1295 7 101 1 29 2 205 4 72 2 3137 25 12 1 – 0

1312 3 276 2 81 7 14 1 4803 7 85 1 30 2 230 4 311 2 4063 25 215 1 – 0

1445 3 365 2 88 6 27 1 1242 6 42 1 39 2 259 4 540 3 6393 25 10 1 – 0

1394 3 198 2 69 7 8.9 1 1876 7 139 1 33 2 134 4 14 2 6690 25 41 1 – 0

690 3 310 2 109 7 13 1 5999 7 19 1 20 2 211 5 29 1 4633 25 10 1 – 0

1167 3 305 2 86 6 32 1 941 6 45 1 42 2 285 4 49 1 7373 25 10 1 – 0

857 3 223 2 39 6 6.4 1 578 6 0 0 22 2 135 4 0 0 4834 24 11 1 – 0

508 3 106 2 50 6 32 1 532 6 0 0 13 2 187 4 25 1 3379 24 4.1 1 – 0

535 3 59 2 33 3 4.2 1 78 3 11 1 8.0 2 35 1 2.3 1 4613 25 2.6 1 – 0

621 3 137 2 54 4 3.1 1 601 6 0 0 21 2 194 4 5.8 1 3890 25 15 1 – 0

487 3 233 2 22 4 1.4 1 972 6 0 0 30 2 47 4 0 0 2217 25 13 1 – 0

441 3 1 1 39 4 1.3 1 337 6 0 0 11 2 26 3 0 0 1515 25 1.4 1 – 0

503 3 2 1 27 3 1.5 1 479 6 0 0 12 2 39 3 0 0 1688 25 7.7 1 – 0

Industry

PCBs and PCNs 86 PAHs 50 Intermediates in organic synthesis 96 Solvents 14 Storage and transfer agents 3 Explosives 6 Other substances of industrial origin 40

27 50 999 33 57 7 9.9 4 1.9 2 – 0 6.1 3

25 41 1572 32 61 8 9.5 4 1.9 2 – 0 8.8 3

35 43 2506 33 157 7 16 4 5.2 2 – 0 12 3

28 51 1897 32 157 8 17 4 2.9 1 – 0 15 3

23 41 1801 32 89 7 15 4 3.1 1 – 0 10 3

24 49 1904 32 83 8 19 4 4.3 2 – 0 16 3

42 52 2091 32 104 9 17 4 5.3 2 – 0 8.7 3

29 51 1806 32 126 7 14 3 3.0 1 – 0 2.4 3

20 50 2056 32 126 8 15 3 0 0 – 0 8.4 3

14 43 1980 33 100 8 14 4 2.3 1 – 0 9.2 3

20 53 2598 32 125 7 10 4 3.1 1 – 0 5.3 3

16 51 2351 33 330 7 13 4 1.9 1 – 0 9.3 3

12 45 1514 33 149 7 8.8 4 1.2 1 – 0 3.9 3

15 54 1396 33 120 7 4.8 3 0.8 1 – 0 2.3 3

7.4 50 329 33 39 7 1.7 1 0.7 2 – 0 2.1 3

4.3 54 1547 32 310 6 6.3 4 0.9 1 – 0 1.0 3

4.1 49 522 33 30 7 8.6 3 0 0 – 0 11 2

1.6 39 484 32 29 7 4.7 3 0 0 – 0 0.014 1

21 47 485 32 21 7 4.9 2 0.30 1 – 0 2.9 3

Sterol

Sterols 10

12 795 17 536 13 579 19 073 22 409 16 706 12 626 12 219 19 117 16 059 9867 9 9 9 9 9 9 9 9 9 9 9

12 796 12 516 6760 9 9 9

4288 9

4030 9

5020 9

2882 9

2599 9

Other

Others 1

3.9 1

157 1

287 1

289 1

299 1

574 1

202 1

6348 142

6095 151

Total 940 Low columns show the number of chemicals.

3.9 1

27 1

14 1

17 1

13 1

35 1

71 1

67 1

57 1

143 1

129 1

209 1

20 166 25 116 27 392 39 140 35 366 33 304 21 368 25 695 31 862 28 835 24 817 26 015 21 040 13 345 10 335 11 730 9917 173 159 163 171 162 174 177 169 169 161 173 170 156 168 151 171 156

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Origin

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of the bay (0.04 at Stn 20 to 0.40 at Stn 3), where a large number of STPs are located, as did coprostanol concentration. The sterol ratios at 9 sites in the innermost part of the bay were higher than 0.2, suggesting that the innermost part of the bay is contaminated by sewage. Nearly 100% of sewage in Tokyo metropolitan area is treated by the activated sludge method. Epicoprostanol is produced as a by-product of sewage treatment and is only present in treated sewage discharges or old samples (McCalley et al., 1981). A plot of the ratio of epicoprostanol/coprostanol against coprostanol/cholesterol can indicate the likely treatment or age in sediments in the bay (Mudge and Duce, 2005). A cross-plot of these ratios indicates that sewage is treated and/or is old (Fig. S3). From these results, we hypothesize that although sediments in the bay are affected by sewage, most of human feces load comes from STP discharges.

Several PAHs indices have been proposed to distinguish petrogenic and pyrogenic sources of PAHs. The ratio of methyphenanthrenes (1-, 2-, 3- and 9- methyphenanthrene) to phenanthrene (MP/P ratio) (Colombo et al., 1989; Zakaria et al., 2002) is one of the most useful indices. MP/P ratios in combustion mixtures are generally

Target and screening analysis of 940 micro-pollutants in sediments in Tokyo Bay, Japan.

Urban societies are using an increasingly diverse array of chemicals, many of which ultimately end up accumulating in urban harbors, where they can ac...
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