Polybrominated diphenyl ethers in e-waste: Level and transfer in a typical e-waste recycling site in Shanghai, Eastern China

Waste Management 34 (2014) 1059–1065

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Polybrominated diphenyl ethers in e-waste: Level and transfer in a typical e-waste recycling site in Shanghai, Eastern China Yue Li, Yan-Ping Duan ⇑, Fan Huang, Jing Yang, Nan Xiang, Xiang-Zhou Meng, Ling Chen State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China

a r t i c l e

i n f o

Article history: Received 28 April 2013 Accepted 5 September 2013 Available online 30 September 2013 Keywords: Polybrominated diphenyl ethers Electronic waste Level and transfer E-waste recycling site

a b s t r a c t Very few data for polybrominated diphenyl ethers (PBDEs) were available in the electronic waste (ewaste) as one of the most PBDEs emission source. This study reported concentrations of PBDEs in e-waste including printer, rice cooker, computer monitor, TV, electric iron and water dispenser, as well as dust from e-waste, e-waste dismantling workshop and surface soil from inside and outside of an e-waste recycling plant in Shanghai, Eastern China. The results showed that PBDEs were detected in the majority of ewaste, and the concentrations of RPBDEs ranged from not detected to 175 g/kg, with a mean value of 10.8 g/kg. PBDEs were found in TVs made in China after 1990. The mean concentrations of RPBDEs in e-waste made in Korea, Japan, Singapore and China were 1.84 g/kg, 20.5 g/kg, 0.91 g/kg, 4.48 g/kg, respectively. The levels of RPBDEs in e-waste made in Japan far exceed the threshold limit of RoHS (1.00 g/kg). BDE-209 dominated in e-waste, accounting for over 93%. The compositional patterns of PBDEs congeners resembled the profile of Saytex 102E, indicating the source of deca-BDE. Among the samples of dust and surface soil from a typical e-waste recycling site, the highest concentrations of R18PBDEs and BDE-209 were found in dust in e-waste, ranging from 1960 to 340,710 ng/g and from 910 to 320,400 ng/g, which were 1–2 orders of magnitude higher than other samples. It suggested that PBDEs released from e-waste via dust, and then transferred to surrounding environment. Ó 2013 Elsevier Ltd. All rights reserved.

1. Introduction Along with the accelerating update of technology and continuous expansion of electronic industrial market, electronic waste (e-waste) becomes a serious global problem in 21st century. As estimated by the United Nations Environment Program, more than 50 million tonnes of E-waste are generated annually in the world (UNEP, 2005). Nevertheless, China is now facing dual pressure of e-waste from both domestic generation and illegal imports (Yang et al., 2008a). The percentage of e-waste amount from overseas was increased to 70% in 2010 and it is estimated that 1.5–3.3 million tons of e-waste are imported to China via illegal ways each year (Zhou and Xu, 2012). It is not only a crisis of quantity but also a crisis of toxic parts (Ongondo et al., 2011; Pant et al., 2012; Xu et al., 2012). Driven by the profit, primitive handlings of e-waste, such as manual disassembling, open incineration and acid dipping, grew up and flourish in a few locations of China (Bi et al., 2007). The inappropriate ewaste recycling and disposal activities generate and release heavy metals and persistent organic pollutants (POPs) into the surrounding environment, which may be redistributed, bioaccumulated and biomagnified, with potentially adverse human health effects ⇑ Corresponding author. Tel./fax: +86 21 65984261. E-mail address: [email protected] (Y.-P. Duan). 0956-053X/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.wasman.2013.09.006

(Söderström et al., 2003; Wang et al., 2005; Wang et al., 2011). Polybrominated diphenyl ethers (PBDEs) are one class of the most concerns because the e-waste contain significant levels of PBDEs (Wang et al., 2005). PBDEs are anthropogenic chemical that have been extensively used as brominated flame retardants (BFRs) in furniture, building material and electronic components. Due to their toxicological effect, the production and use of PBDEs have been banned in Europe, meanwhile, penta- and octa-BDE formulations are now banned in North America (Kemmlein et al., 2009; Ward et al., 2008). Uncontrolled e-waste recycling activities have become a new important source of PBDEs. High levels of RPBDEs were detected in soil from acid leaching site (2720–4250 ng/g, dry wt.), and from a printer roller dump site (593–2890 ng/g, dry wt.) at Guiyu, Southeast China (Leung et al., 2007). They were also found in soils (up to 25,479 ng/g, dry wt.), and sediments (up to 3526 ng/g, dey wt.) in Taizhou, Southeast China (Yang et al., 2008b, 2009). PBDEs were detected in various environmental samples in e-waste recycling areas in China indicating a severe risk to the local ecosystem and inhabitants’ health (Bi et al., 2006; Luo et al., 2009a). Yet, most of the previous researches were focused on the environmental media. Only limited and rather uncertain data are available regarding the occurrence of PBDEs in e-waste (the emission source). High concentrations were found in housings shredder residues (Schlummer et al., 2007). Average concentrations in small

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size e-waste amounted to 0.03 g/kg for penta-BDE, 0.53 g/kg for octa-BDE, and 0.51 g/kg for deca-BDE (Morf et al., 2005). Levels and patterns of PBDEs in e-waste may also be relevant to the component types, production time, producing region, however, researches in this area are still blank. So it is necessary to study the characterization of PBDEs in e-waste deeply and systematically, in order to provide rationalization proposals regarding proper handling of e-waste and the development of management policies. Located in the Eastern China, Shanghai is the largest and most populous city of China. Meanwhile, technological innovation and intense market bring a rapid replacement process leading to increasing generation of waste electrical and electronic equipment (WEEE) in Shanghai. As shown in Fig. 1, part of electrical and electronic equipment enter the circulation in the secondary market. In addition, to enter the recycling link is the most important way for e-waste. There are several e-waste recycling sites in Shanghai, even though the handling capacity is limited. Many studies suggested that a major emission source of PBDEs is the low-tech e-waste recycling facilities (Ma et al., 2009b). Their impact on the surrounding environment can never be ignored. In the present study, 140 e-waste plastics samples were collected from e-waste recycling sites in Shanghai to investigate levels and compositional patterns of PBDEs in e-waste. Detailed information of PBDEs in e-waste such as time series was also discussed. Additionally, dust in e-waste, dust in dismantling workshop, surface soil inside and outside the e-waste recycling plant were collected to investigate the possible transfer during recycling process.

2. Materials and methods 2.1. Sample collection Sampling campaigns were conducted between September 2008 and March 2009. A total of 157 samples were collected from ewaste recycling sites in Shanghai, including plastics, dust and surface soil. Briefly, plastics samples were cut from plastic housing of e-waste which were near the vents. As for the same types of plastic housing of e-waste, plastics were cut from the same position of the electronics with the same size was almost the same. Dust in e-waste was collected by vacuum-cleaning the inside of each e-waste until sufficient mass (>300 mg) was collected on a glass fiber filter. Dust in dismantling workshop were collected from the floor inside the dismantling workshop using a straw brush. Surface soil samples were collected outside the workshop in

e-waste recycling plant and in a place at a distance of about 1 km from the e-waste recycling plant using a stainless steel shovel at a depth of 1–10 cm, respectively. All the samples were wrapped in aluminum foil and stored at -20 °C in the laboratory prior to analysis. Besides, the dust and surface soil samples were air-dried and sieved through 100 mesh screen before storing. 2.2. Standard materials The targets 19 PBDEs congeners were purchased from Accu Standards (New Haven, CT, USA), including three tri-BDEs (BDE-17, BDE28, and BDE-33), three tetra-BDEs (BDE-47, BDE-49, and BDE-66), two penta-BDEs (BDE-99 and BDE-100), three hexa-BDEs (BDE138, BDE-153, and BDE-154), four hepta-BDEs (BDE-183, BDE-190, BDE-196, and BDE-203), three nona-BDEs (BDE-206, BDE-207, and BDE-208), and deca-BDE (BDE-209). BDE-50 and BDE-172 used as surrogate standards and BDE-118 and BDE-128 used as internal standards were also purchased from AccuStandards. 2.3. Sample extraction and PBDEs analysis The plastic samples of e-waste were firstly cleaned by distilled water, then cut into tiny fragments. These plastic fragments were prepared to ‘‘polymer film’’ to facilitate a complete extraction. Detailed extraction is provided in our previous study (Huang et al., 2010). Dust and surface soil samples were weighed approximately 200 mg and 5 g respectively, and then extracted. The following procedures are the same as our previous study (Yang et al., 2011). PBDEs congeners were quantified with a Shimadzu GCMSQP 2010 plus instrument with the selective ion monitoring (SIM) mode. A DB-5 column (15 m  0.25 mm  0.1 lm, J&W Scientific) was employed. For the analysis of tri- to hepta-BDE congeners, temperature program was 80 °C for 1 min, ramped at 12 °C/min to 140 °C, then 5 °C/min to 280 °C and held for 20 min. For octato deca-BDE congeners, the program was 110 °C for 1 min, ramped at 10 °C/min to 290 °C and hold for 20 min. Quantification of the target compounds was performed using an internal standard method. With a signal/noise ratio of better than 3, the limit of detection (LOD) for BDE-209 and other congeners were 2 ng/g and 0.1 ng/g based on dry weight, respectively. 2.4. Quality assurance and quality control For each batch of e-waste plastic, dust and surface soil samples, a procedural blank, a spiked blank and a duplicate sample were processed. All targets were lower than the LOD in procedural blanks, so they were not subtracted from the sample measurement. The surrogate recovery of BDE-50 and BDE-172 was 99 ± 3.9% and 102 ± 3.5%, respectively. The relative standard deviation for individual PBDEs congener was less than 10% (n = 5). Recoveries of targets ranged from 82% to 119%, relative standard deviations ranged from 2.1% to 8.3% in spiked blank samples. Reported concentrations were not surrogate recovery corrected. 3. Results and discussion 3.1. Levels of PBDEs in e-waste

Fig. 1. The flow chart of electrical and electronic equipment in Shanghai.

The e-waste plastics samples were categorized into six types according to the application of electrical and electronic products, including printer (n = 11), rice cooker (n = 5), computer monitor (n = 13), TV (n = 102), electric iron (n = 2), and water dispenser (n = 7). Fig. 2 presents detectable frequency and the concentrations of RPBDEs in different types of e-waste. PBDEs were detected in 71

Y. Li et al. / Waste Management 34 (2014) 1059–1065

samples of all, with total detection frequency of 51%, which indicated the frequent use of PBDEs in the plastics of EEE. Previous studies also reported PBDEs were detected in 40% of all BFRs containing housing samples (Schlummer et al., 2007), even much higher (78%) in the other research (Riess et al., 2000). The positive rate in rice cooker and water dispenser was 40%, 57% respectively. Many researchers have reported that dietary intake is the most relevant route for human exposure (Bocio et al., 2003; Johnson-Restrepo and Kannan, 2009; Meng et al., 2007), which amounted to 93% in the U.K. (Harrad et al., 2004) and 96% in Canada(Wilford et al., 2004). Therefore, much attention should be paid to the household electric appliances having a close relationship with human. The levels of RPBDEs varied between not detected and 175 g/kg with an average of 10.8 g/kg in this study, which were higher than those reported in previous study (2–22 g/kg) (Schlummer et al., 2007). According to ‘‘Restriction of the Use of certain Hazardous Substances in Electrical and Electronic Equipment (RoHS)’’ directive, there is an upper threshold limit (1.00 g/kg) for the concentration of RPBDEs. The RPBDEs concentrations of one-third samples exceeded the RoHs threshold limit. The percentage that exceeding the RoHs threshold limit were 28%, 54% and 9.1% for TV, computer monitor, and printers, respectively. This may be due to the different flame retardants added to these products (Tasaki et al., 2004). Among all the samples in this study, the concentrations of RPBDEs in TV plastics were higher than others. The contents of PBDEs in TV plastic during different time is shown in Table 1. PBDEs were not detected in the samples made in late 1980s (1985–1990), yet they were detected in the samples made after 1990 in this study. It indicated that PBDEs were possibly introduced in TV plastics from about quite the early 1990s in China. Tanikawa reported (Tasaki et al., 2004) that Br was not detected in front covers of TV plastic made in Japan from 1987 to 1990, but was detected in those after 1990. The time period was the same. However, Tasaki found that PBDEs were used in rear plastic covers of TV beginning around 1987–1990 (Tasaki et al., 2004), which was earlier than the result of this study. Responses obtained from five major TV manufacturers in Japan confirm these figures and provide the following information: the Electronic Industries Association of Japan Guideline’s targets applied only to the rear covers and the substitution measures were costly; therefore, measures were taken relatively late. Consequently, BFRs were being used for rear covers beginning 1987–1990 and for front covers in 1993–1996. In order to make clear the time-series of PBDEs in TVs made in China, several TVs made in different years were selected (Fig. 3). After that earlier 1990s, the concentrations of RPBDEs in TV plas-

Concentration of ΣPBDEs (g/kg)

1000

RoHS threshold limit 100

10

1

0.1 (9/11)

(2/5)

(8/13)

(46/102)

(2/2)

(4/7)

0.01

r nt e pri

oo ec ric

ker

p com

o rm ut e

or nit

TV

r n iro nse ric spe i t c d ele ter wa

Fig. 2. The concentrations and the detectable frequency (number of samples detected with PBDEs/total number of samples) of RPBDEs in different types of ewaste.

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tics increased greatly. They ranged from not detected to 50.28 g/ kg. The concentration variation may be attributed to the different manufacturers. The value of the vast majority of TVs made in 1995–1998 far exceed the threshold value of RoHS directive. Comparison with long-term monitoring data of environmental samples (such as sediment, aquatic biota, human blood and milk), the timeseries trends had much better consistency. The concentrations of RPBDEs in blubber of male finless porpoises collected from South China sea ranged from a minimum of 84 ng/g lipid wt. in 1990, to a maximum of 980 ng/g lipid wt. in 2001, showing a significant increase during the time period investigated (Ramu et al., 2006). In the study of sediment cores from the Pearl River Estuary, South China, the BDE-209 concentrations remained constant until 1990 and thereafter increased exponentially to the present, with doubling times of 2.6 ± 0.5–6.4 ± 1.6 years, suggesting the increasing market demands for deca-BDE mixture after 1990 in China (Chen et al., 2007). 3.2. PBDEs in e-waste from different countries The samples of e-waste in this study were divided into 4 groups according to their countries of origin. Fig. 4 presents a summary of the data from this study and comparison with other previously reported values. The mean concentrations of RPBDEs in e-waste plastics in this study were 1.84 g/kg, 20.5 g/kg, 0.91 g/kg, 4.48 g/ kg, which were made in Korea (n = 4), Japan (n = 24), Singapore (n = 4) and China (n = 80), respectively. The research of PBDEs in household products in South China reported that the mean concentration was 0.075 g/kg (Chen et al., 2010), which was much lower than that in this study. It may be caused by the different kinds of samples and the different manufacturer of the electronics. The range of levels found in Japan in this study far exceed the threshold limit of RoHS, which was in good agreement with those found in the previous studies (Choi et al., 2009; Takigami et al., 2008; Tasaki et al., 2004). Much PBDEs were added in household appliances in Japan in 1980s and 1990s. This may be due to no restrictions on the use of these substances at that time. Kim et al. reported the data of Korea (25 g/kg) was higher than this study (Kim et al., 2006). It probably because the TVs were produced by different manufacturer. The limited data on PBDEs from other countries were lower: America (2.40 g/kg, n = 7) (Petreas and Oros, 2009), Germany (0.70 g/kg, n = 45) (Schlummer et al., 2007), Switzerland (3.93 g/kg, number of samples was unknown) (Morf et al., 2005). However, due to the small number of samples, the results can not exactly represent the complexity of the actual situation but only reflected the adding situation of PBDEs in these countries to a certain extent. The different levels of PBDEs among countries may be attributed to differences of the production processes and the requirements to flame retardant grade. Although the concentration of RPBDEs was not so much high, the amount of e-waste was astonishing. The current global production of ewaste is estimated to be 50 million tonnes per year. Switzerland produces 9 kg per person per year. Europeans produce e-waste at a rate of 14 kg per person per year, making a total annual e-waste production for the 15-member-state European Union (EU-15) of 5.5 million tonnes per year, and the EU-27 of 8.3–9.1 million tonnes per year. The United States produced 2.63 million tonnes in 2005, while China produced 2.5 million tonnes (Robinson, 2009). Taking the large volume of e-waste into consideration, more attention should be paid to the total amount of PBDEs released to environment via e-waste. 3.3. Compositional patterns of PBDEs congeners in e-waste The penta-, octa-, and deca-BDE technical mixtures are primarily used as additive flame retardants in raw materials, semi manu-

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Table 1 Content of RPBDEs /Br in covers of TV. Concentration (mg/kg)

Manufacturing year

RPBDEs Br RPBDEs

Ref.

1987–1989

1990–1993

1994–1998

35,711 ND ND

90,883 Detected 477

76,777 Detected 12,295

Tasaki et al. (2004) Tasaki et al. (2004) This study

10

1

)

)

/1 (1

(4

/6 (6

/6

)

)

)

/2 (1

0)

/8

/1 (5

(4

)

)

/2

(5

(1

/6

) /4 (1

(0

/4

)

)

(0

/4

/4

/2 (0

(0

)

0.1

)

Concentration of ΣPBDEs (g/kg)

100

02 20

98 19

97 19

96 19

95 19

94 19

92

93

19

19

91 19

90 19

85

88 19

19

19

86

0.01

Fig. 3. Time-series analysis of concentration and the detectable frequency (number of samples detected with PBDEs/total number of samples) of RPBDEs in the TV plastics made in China.

factured, or end products. A summary of the detectable rate of PBDEs congeners in e-waste was presented in Fig. 5a. It was found that in all samples, the detectable rate of deca-BDE was 80%, with octa-BDE holding 9.1% and penta-BDE covering 5.5%. The much higher positive rate of deca-BDE was more likely due to the almost exclusive use of deca-BDE mixture in electronics when the sampled electronic products were manufactured. The congener profiles of PBDEs in e-waste samples made in China appeared centralized distribution in Fig. 5b. It was found that BDE-209 dominated in all congeners, which accounted for over

93%, followed by BDE-99 (2.5%) , BDE-47 (1.8%) , BDE-183 (1.3%) , BDE-100 (0.5%) , and BDE-153 (0.3%).This is consistent with the usage of PBDEs mixtures in China, where BDE-209 is the dominant congener (Alaee et al., 2003; La Guardia et al., 2006). Besides, PBDEs congener profiles of atmosphere, soil and other samples collected in China are also similar, with BDE-209 accounting for 70– 90% (Chen et al., 2009a; Leung et al., 2007; Qu et al., 2007). The composition patterns of PBDEs in e-waste samples can reflect their origin. In order to trace the source of PBDEs, the congener composition was compared to the PBDEs pattern in commercial products. Fig. 5c presented PBDEs congeners in ewaste samples and two technical products Saytex 102E and Bromkal 82-0DE. As shown in Fig. 5c, composition of BDE-209 in e-waste (97%) is similar to that of the major components of the commercial deca-BDE technical product Saytex 102E(96.8%), indicating that Saytex 102E may be one of the major deca-BDE industrial products added into plastics during EEE manufacturing process (La Guardia et al., 2006). As shown in Fig. 5e, congeners pattern of BDE-47, 99, and 100 in e-waste closely resembled the pattern in the commercial penta-BDE product DE-71, indicating that the penta-BDE probably stemmed from this commercial penta-BDE product. Octa-BDE as a commercial product also contains many PBDEs congeners with different degrees of bromination (Pohlein et al., 2008). A noticeable difference in octa-profiles between e-waste and commercial octa-products was observed in Fig. 5d. E-waste contained a much lower proportion of BDE-183 and BDE-153. There are probably four influencing factors: (1) two commercial octa-BDE products were both used in these collected samples; (2) other commercial octa-BDE product were added in EEE; (3) highly brominated congeners in deca-BDE generated some congeners in octa-BDE product during the degradation; (4) octa-BDE may have been subject to photolytic or thermal degradation or other complex processes during the manufacturing and using procedure. Likewise, the last point has been suggested by Chen et al. In 14 foam toys, the content of nona-BDE and octa-BDE exceeded those of deca-BDE (Chen et al., 2009b). However, the degradation of highly brominated BDE congeners in the products remains controversial (Betts, 2008). It showed relatively high similarity of decaBDE profiles between technical products and the samples (Fig. 5c). It further indicates that the abundant deca-BDE industrial

Fig. 4. The concentrations of PBDEs in e-waste in different countries (The length of column represents the logarithm of RPBDEs concentration. Data in the dashed box was measured in this study).

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(c)

(b)

BDE-209

BDE-47 BDE-99 BDE-100

Others

Bromkal 82-0DE

BDE-153 BDE-183

Saytex 102E

BDE-209

WEEE

0

20

40

60

80

100

WEEE

0

2

4

(a)

(d)

0

20

BDE-153

BDE-183

BDE-209

Others

40

60

6

90

100

Composition (%)

Composition (%)

80

deca-BDE (80.0%) octa-BDE (9.1%) penta-BDE (5.5%) Others (5.4%)

(e)

BDE-47

BDE-99

BDE-100

Others

Bromkal 79-8DE

Brokmal 70-5DE

DE-79

DE-71

WEEE

WEEE

100

0

20

Composition (%)

40

60

80

100

Composition (%)

Fig. 5. The BDE congener profiles and proportion of three types of PBDEs in e-waste and commercial products. (a) Detectable rate of PBDEs congeners; (b) Congener profiles in e-waste made in China; (c) Congener refer to deca-BDE; (d) Congener refer to octa-BDE; (e) Congener refer to penta-BDE (‘‘others’’ refer to other congeners of PBDEs except those given in figure).

3.4. Transfer of PBDEs in e-waste recycling site The mean concentrations of R18PBDEs (excluding BDE-209) and BDE-209 in dust in e-waste were 4930 ng/g dw (ranged from 667 to 20,300 ng/g dw) and 42,300 ng/g dw (ranged from 910 to 320,400 ng/g dw), with BDE-209 accounting for the major proportion of RPBDEs (89.6%) (Fig. 6). The concentration of R18PBDEs in dust in dismantling workshop was slightly higher than that in dust in e-waste, however, the concentration of BDE-209 in dust in dismantling workshop was much lower than that in dust in e-waste. It may be suggested that BDE-209 is more readily debrominated to lower BDE congeners under the changes of pressure and temperature used during the low-tech recycling operations. However, other factors likely affect the concentrations, such as the mechanisms of PBDEs entering the dust and the difference of dust matrixes. Although many studies in different countries have reported PBDE concentrations in dust and soil samples, comparisons among studies are difficult because of inconsistencies in the congeners analyzed. Table 2 summarizes the reported RPBDE concentrations in soils from different countries and regions. A simple comparison based on concentrations was made between our data and these values. As shown in Table 2, the highest concentrations of RPBDEs and BDE-209 were observed in dust in e-waste, which were several orders of magnitude higher than other samples. It can be deemed to one emission source of PBDEs. The R18PBDEs concentrations in dust inside TV cabinets (Takigami et al., 2008) were much higher than this study. This suggested that the TVs from Japan contained much higher PBDEs concentration. The concentrations of R18PBDEs and BDE-209 in dust in dismantling workshop and surface soil in the recycling plant were comparable to the same type samples from other studies (Gao et al., 2011; Leung et al., 2007; Ma et al., 2009a; Muenhor et al., 2010; Wang et al., 2009). As for surface soil near e-waste disposal site, the R18PBDEs concentrations in soil near an e-waste open burning site (143 ng/g) were 1 order of magnitude higher than those from other study (Wang

Σ18PBDEs Concentration of PBDEs (ng/g)

products added in household appliances may exists little possibility of substantial debromination degradation. Therefore, more efforts are needed in determining the degradation of PBDEs commercial products in the waste plastics.

BDE-209

1e+5

1e+4

1e+3

1e+2

1e+1

DEW

DDW

SRP

SoRP

Fig. 6. Concentrations of R18PBDEs (except for BDE-209) and BDE-209 in dust and soil samples from e-waste recycling site. (DEW: dust in e-waste; DDW: dust in dismantling workshop; SRP: surface soil in e-waste recycling plant; SoRP: surface soil out of e-waste recycling plant.)

et al., 2011). It can be seen that rude e-waste recycling techniques generate much pollution. The concentrations of RPBDEs and BDE-209 showed a noticeable decreasing trend with the distance from the e-waste recycling site (Fig. 6). It was obvious that the diffusion of PBDEs from the point pollution source made a dominant contribution to PBDEs contamination in the surrounding areas. PBDEs in e-waste firstly were transferred into dust in e-waste directly or into dust in the workshop via shred in the recycling plant. Then, PBDEs might be diffused from the dismantling workshop to the whole recycling plant then to surrounding areas via air transport and dry/wet deposition. The influence of point pollution source to the surrounding environment has been termed the ‘‘halo effect’’ (Pier et al., 2003). Zhao et al. (2009) also found that PBDEs from the e-waste recycling area diffused into the ambient regions, and resulted in a halo pattern of PBDE contamination at least 74 km in radius. The inappropriate recycling and disposal of e-waste became an important source for PBDEs, resulting in serious environmental problems and increased environmental burden.

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Table 2 Concentrations (ng/g, dry weight) of R18PBDEs and BDE-209 in dust and soil samples in the present study and those from other studies. Type

Source

R18PBDEs

BDE-209

Ref.

Dust in E-waste

Dust inside TV cabinets (n = 5)

Dust in workshop

Dust in E-waste (DEW, n = 11) Dust in electronic waste storage facilities in Thailand (n = 25)

223,000(56,000– 490,000) 42,300(910–320,400) 20,000(250–250,000)

Soil near E-waste disposal site in Zhejiang, China (n = 48)

653

29,800(5,600– 80,600) 20,600(13,900– 27,400) 148(1.20–356)

Takigami et al. (2008) This study Muenhor et al. (2010) Ma et al. (2009b))

Dust in dismantling workshop (DDW, n = 2)

105,000(11,000– 212,000) 4930(667–20,300) 28,000(320– 290,000)a 30,700(6,300– 82,200)a 6,560(5,570–7,540)

Soil in acid leaching in Guangdong, China (n = 3)

980.1

1270

Soil in printer roller dump site in Guangdong, China (n = 3)

858

Soil in E-waste recycling site in Guiyu, China (n = 6) Soil in E-waste recycling site in Qingyuan, China (n = 4) Soil in E-waste facility in Eastern China (n = 10) Surface soil in E-waste recycling plant(SRP, n = 2)

663(22–1853) 455(7.2–1188) 1910(72–5710)a 626(184–1,069)

2,246(105–5,224) 2,775(779–8,058) 1800(70–5530) 3073(296–5850)

Leung et al. (2007)) Leung et al. (2007)) Gao et al. (2011) Gao et al. (2011) Ma et al. (2009b) This study

Soil near an E-waste open burning site in Guangdong, China (n = 5) Soil surrounding e-waste recycling sites in Guiyu, China (n = 23) Soil surrounding e-waste recycling sites in Qingyuan, China (n = 27) Farmland soils near dismantling workshop in Guangdong, China (n = 18) Soil out of E-waste recycling plant(SoRP, n = 2)

143(77.3–249)

154(66.7–284)

Wang et al. (2011)

7.53(0.13–58.8)

31.6(0.73–245)

Gao et al. (2011)

8.26(0.22–38)

47.9(3.62–538)

Gao et al. (2011)

10(1.7–28.8)

32.2(3.5–178.5)

Luo et al. (2009b)

57(34–79.4)

214(110–318)

This study

Soil in municipal waste dumping sites in Cambodia

32(0.54–91)a

21(0.16–71)

Soil in municipal waste dumping sites in India

7.3(0.82–19)a

5.4(0.48–16)

Surface soils from the Yangtze River Delta , China(n = 22) Agricultural soil in Shanghai, China(n = 36)

0.761(0.164–2.25) 0.175(0.041–0.962)

11.9(0.08–24.5) 0.254(0.034–0.796)

Eguchi et al. (2013) Eguchi et al. (2013) Duan et al. (2010) Jiang et al. (2012)

Dust in E-waste facility in Eastern China(n = 5)

Surface soil in E-waste disposal site

Surface soil near E-waste disposal site

Others

a

510

This study Wang et al. (2009)

Sum of detected BDE (including BDE-209).

4. Conclusions

References

The study provided an overview of the concentration of PBDEs in e-waste plastics. PBDEs were detected in over half samples, indicating the frequent use of PBDEs in electronic products. The concentrations of PBDEs in approximately one-third samples exceeded the ‘‘RoHS threshold limit’’. The time series of PBDEs in TV sets showed that the use of PBDEs began in 1990 in China, which could give guidance on the recovery and disposal of waste TV sets in China. BDE-209 contributed more than 90% to the total PBDEs in all e-waste samples, indicating that Deca-BDE commercial mixture may be the major formula used in the electronic products. The concentrations of RPBDEs showed a significant decrease trend among dust in e-waste, dust in dismantling workshop, surface soil in e-waste recycling plant, and surface soil out of e-waste recycling plant. This further proved that the diffusion of PBDEs from the point pollution source made a dominant contribution to PBDE contamination in the surrounding areas. Hence, further work shall be directed towards a systematic examination concerning the release mechanism of PBDEs from e-waste to environmental medium. Such data would serve to discuss different recycling/disposal scenarios and the risk assessment of potential hazards.

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Acknowledgments This study is financed by Shanghai Postdoctoral Scientific Program (13R21416000), Innovation key Program for Scientific Research, Shanghai municipal education commission (12ZZ035) and National Key Technology R&D Program (2012BAJ24B01).

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