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Organochlorine pesticides contamination in surface soils from two pesticide factories in Southeast China
Chemosphere 77 (2009) 628–633
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Organochlorine pesticides contamination in surface soils from two pesticide factories in Southeast China Lifei Zhang, Liang Dong, Shuangxin Shi, Li Zhou, Ting Zhang, Yeru Huang * State Environmental Protection Key Laboratory of Dioxin Pollution Control, National Research Center for Environmental Analysis and Measurement, No. 1 Yuhui Nanlu, Chaoyang District, Beijing 100029, China
a r t i c l e
i n f o
Article history: Received 18 May 2009 Received in revised form 11 August 2009 Accepted 27 August 2009 Available online 20 September 2009 Keywords: Organochlorine pesticides Soil Contamination Southeast China
a b s t r a c t The present article attempts to investigate organochlorine pesticides’ (OCPs) contamination in soils from polluted sites and to assess the soil quality in the study area. HCHs and eight other persistent organic pollutants (POPs) pesticides were studied in surface soil samples collected from a new (F) and an old (G) pesticide factory in Southeast China. According to the measured results, surface soils from F and G were contaminated with HCHs, DDTs, HCB, and chlordane, with b-HCH and p,p0 -DDT being the two dominant substances. The total OCPs concentrations of surface soils from F and G were 0.84 and 166 mg kg1 respectively. Cluster analysis was performed to group the soil sites in terms of their total OCPs contamination levels. The ratios of a-HCH/c-HCH, o,p0 -DDT/p,p0 -DDT, and trans-/cis- chlordane in some of the soil samples are similar to their technical products in the study area which indicates the lack of hazardous waste management practices of the pesticide production and transportation. According to GB 156181995, the HCHs could be classified as light pollution and little pollution for F and G, whereas DDTs levels of F and G could be defined as little pollution and heavy pollution, respectively. This study indicates that surface soils, especially residential area soils from F and G were facing varying degrees of pollutions. The situation is more hazardous due to the continuous exposure of the population that lives in the surroundings. Therefore, on-site remediation technologies and the best available techniques/best environmental practices (BAT/BEP) should be carried out on these factories with the national implementation of the Stockholm Convention. Ó 2009 Elsevier Ltd. All rights reserved.
1. Introduction Organochlorine pesticides (OCPs) are a set of chemicals that are toxic, persist in the environment for long periods of time, and biomagnify as they move up through the food chain (Kretchik, 2002). They have been linked to adverse effects on human health and animals and were classified to persistent organic pollutants (POPs). A large quantity of OCPs were produced between the 1950s and the 1980s with about 4460 000 t technical HCHs and 435 200 t DDTs (Cao et al., 2007). In 1990, 148 kinds of pesticides, amounting to 226 000 tons, were produced in China, ranking third in the world (Wang et al., 2005). Application of pesticides can improve crop yields for agriculture, but soil adsorption may occur as well, especially for carbon-rich soils (Holoubek et al., in press). These pesticides present a vast history of environmental contamination all over the country, especially in Southeast China (Cao et al., 2007). With the signing of the Stockholm Convention and the development of global monitoring programs, there is an increasing need * Corresponding author. Tel.: +86 10 8466 5753; fax: +86 10 8463 4275. E-mail address: [email protected] (Y. Huang). 0045-6535/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2009.08.055
for developing countries to monitor OCPs in various environmental compartments (Abhilash and Singh, 2008). Recent surveys and monitoring have reported relatively high levels of OCPs in soils from Southeast China (Wang et al., 2005; Cao et al., 2007; Hao et al., 2008). However, assessment on the OCPs in soil is difficult because of the lack of representativeness of data. In this study, two pesticide factories in Southeast China were selected as the typical contamination sites. A total of 24 surface soil samples were collected at five land-use types of soil around these two factories. Organochlorine pesticides, including HCHs and 8 other POPs pesticides were determined to evaluate the extent to which contamination of OCPs varied. The major purpose of this study is to: (1) investigate the concentrations, compositions and distributions of OCPs in two pesticide factories in Southeast China, and (2) to assess the soil quality and to evaluate the potential risks to human health and environmental safety in this area. Furthermore, the remediation methods for those contaminated sites would also be discussed. This paper presents the current status of OCPs residues on contamination sites. The dataset generated will enrich the knowledge on contamination sites such as pesticide factories.
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2. Materials and methods 2.1. Chemicals and reagents A mixed stock standard solution of OCPs containing a-HCH, bHCH, c-HCH, d-HCH, o,p0 -DDE, p,p0 -DDE, o,p0 -DDD, p,p0 -DDD, o,p0 DDT, p,p0 -DDT, hexachlorobenzene, oxy-chlordane, trans-chlordane, cis-chlordane, heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, methoxychlor, and mirex at a concentration of 100 mg L1 was purchased from Chem Service, Inc., USA. The surrogate (13C-p,p0 -DDT) and the internal standard (deuterated phenanthrene, deuterated pyrene, and deuterated chrysene) were purchased from AccuStandard, Inc., USA. Acetone, n-hexane and methylene chloride (for organic residue analysis) were obtained from J.T. Baker, USA.
cleaned up with a Florisil solid phase extraction (SPE) cartridge (1 g, 6 mL, Supelco, USA). After the sample was transferred onto the cartridge, it was then eluted with 12 mL acetone/hexane (2/ 98, v/v). The eluate was concentrated to about 1 mL under a centrifugal vacuum evaporator system (CVE3100, Eyala, Japan). Twenty microlitres of deuterated phenanthrene, deuterated pyrene, and deuterated chrysene mixture standard solution (10 ng lL1) was added to the solution as injection internal standard prior to transferring to a glass microvial for GC injection. 2.4. OCPs determination
Samples were collected in July, 2008 from two pesticide factories, F (32°100 3200 N, 119°360 2400 E) and G (32°220 2300 N, 119°250 3500 E) in Jiangsu Province, in southeast of China. F is a new factory which was built in 2000, whereas G is a famous pesticide factory in Southeast China which was built in the 1950s. A total of 24 surface soil (0–10 cm) samples were collected around the factories with 9 for F and 15 for G. At each site, composite surface soil samples were collected from four locations 2 m apart (200 g each) and thoroughly mixed. Three soil samples were collected from each site. The 24 sampling sites were derived from five different land-use types of soil surrounding F and G (see Table 2).
The determination of OCPs was performed on a Shimadzu GCMS-QP2010 equipped with a fused silica capillary DB-5MS column (30 m 0.25 mm i.d., film thickness: 0.25 lm) using electron ionization with selective ion monitoring mode. High purity (99.99%) helium was used as carrier gas at 0.98 mL/min. The injector, transfer line, and ion source temperature were 250 °C, 260 °C, and 230 °C respectively. The oven temperature program was as follows: initial temperature 70 °C held for 1 min, increased to 180 °C at 20 °C/min, then to 260 °C at 4 °C/min, and to 300 °C at 15 °C/min, held for 6 min. Two microlitres of each sample was injected in the spilt mode with 1:14.1. Injection internal standards were used for quantification. OCPs measured in soils include four HCH isomers, six DDT homologues, HCB, oxy-chlordane, trans-chlordane, cischlordane, heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, methoxychlor, and mirex. Concentrations of RHCHs, RDDTs and RCDs were the R of the four HCH isomers, six DDT homologues and three chlordane (oxy-chlordane, trans-chlordane, cis-chlordane), respectively.
2.3. Sample extraction and cleanup
2.5. Quality control
Each fully mixed soil sample was air-dried, sieved through a 1 mm mesh, and ground before analysis. After 20 lL of 13C-p,p0 DDT (5 ng lL1) added as surrogate and 2.0 g active Cu added to eliminate element sulfur, 5.0 g soil was extracted by accelerated solvent extraction (ASE 300, Dionex, USA), using 1:1 methylene chloride/acetone as extracting solvent at 100 °C. The extract obtained was concentrated to approximately 1 mL and further
The detection limit ranged from 0.014 to 0.178 lg kg1 for OCPs. The method blanks showed no detectable target compounds. Surrogate was added to all the soil samples. The recoveries of 13Cp,p0 -DDT by this method fell within the range of 75–125%. All reported values were corrected by the field blanks and surrogate recovery. Quality control was performed on the analysis of Standard Reference MaterialÒ 1944 (SRM 1944, New York/New Jersey
2.2. Soil sampling
Table 1 Method detection limit (MDL) and comparison between determined and SRM 1944 certified values (lg kg1) (nd: not detected; na: not available). Name
MDL
Determined value
Certified value
Name
MDL
Determined value
Certified value
a-HCH
0.020 0.019 0.045 0.021 0.026 0.031 0.041 0.033 0.178 0.088 0.034
nd 5.84 ± 0.40 nd nd nd nd nd nd nd nd 22 ± 4.5
2.0 ± 0.3 6.03 ± 0.35 na na na na na na na na 8±2
o,p0 -DDE cis-Chlordane p,p0 -DDE Dieldrin o,p0 -DDD Endrin p,p0 -DDD o,p0 -DDT p,p0 -DDT Methoxychlor Mirex
0.014 0.033 0.028 0.068 0.013 0.101 0.014 0.024 0.051 0.048 0.022
17 ± 3.9 14.1 ± 2.4 108 ± 16 nd 45.8 ± 12 nd 118 ± 14 107 ± 94 128 ± 52 nd nd
19 ± 3 16.51 ± 0.83 86 ± 12 na 38 ± 8 na 108 ± 16 na 119 ± 11 na na
HCB b-HCH c-HCH d-HCH Heptachlor Aldrin Heptachlor epoxide A Oxy-chlordane Heptachlor epoxide B trans-Chlordane
Table 2 Organochlorine pesticides concentration (lg kg1) in surface soils from F and G. Sites type
Sites
RHCHs
RDDTs
HCB
RCDs
OCPs
River bank Roadside Vegetable plot Residential area Factory gate
G1, G2, G3, G15 F1, F2, F3, F4, F5, F6, F7, F8, G12 G4, G5, G11 G6, G7, G8, G9, G13, G14 F9, G10
2.88 ± 3.1 0 1.64 ± 2.8 34.9 ± 33 313 ± 399
2339 ± 1620 22.8 ± 51 661 ± 478 14,329 ± 5510 33,748 ± 47,730
1.92 ± 1.7 0.788 ± 1.4 0.637 ± 0.5 47.2 ± 45 112.2 ± 116
8.43 ± 15.0 0 0.081 ± 0.14 0.972 ± 1.07 0.335 ± 0.47
2352 ± 1167 23.6 ± 11 663.7 ± 330 14,412 ± 7150 34,173 ± 16,800
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Waterway Sediment). The average values of OCPs determined and the standard deviation of triplicate samples by this method are in Table 1. 2.6. Statistical analysis Conventional statistical analysis and cluster analysis were carried out using SPSS 16.0. 3. Results and discussion 3.1. OCPs concentration and soil quality assessment Analysis results showed that most of the OCPs were found in samples except heptachlor, heptachlor epoxide, methoxychlor, aldrin, dieldrin, endrin, and mirex. In general, the total OCPs concentrations of surface soils from F and G were 0.84 and 166 mg kg1 respectively. The total OCPs concentration of G is approximately 200 times as much as that of F, since it has more than 30 years history than F. In another way, plant uptake from the polluted site could reduce the soil contamination when paralleling F with G. However, on-site remediation technologies are urgently needed to eliminate OCPs contamination in the study area. The average concentrations of RHCHs, RDDTs, RCDs, and HCB of F and G were 66.1, 5.14, <0.033, 22.3 lg kg1 and 17.1, 10,998, 2.70, 21.6 lg kg1, respectively. They were much lower than the average concentrations of RHCHs (53–99 mg kg1) and RDDTs (3800– 7300 mg kg1) found in some reported heavily contaminated sites (Villa et al., 2006; Abhilash and Singh, 2008). However, the total HCHs at both factories and total DDTs at F were comparable or slightly higher than surface soils from Bacninh, Vietnam (Toan et al., 2009), but much higher than agricultural soil of Shanghai (Jiang et al., in press). Samples were grouped according to the soils of river bank, roadside, vegetable plot, residential area, and factory gate. The concentrations of RHCHs, RDDTs, HCB, RCDs, and total OCPs in various soils collected from F and G are presented in Table 2, as mean ± standard deviation. The total OCPs concentrations in soil samples were as follows: factory gate > residential area river bank > vegetable plot > roadside. Therefore, the OCPs concentration in factory gate soils were found not significantly (p < 0.05) different from residential area soils, suggesting that residential area soils were similar to factory gate soils, and were heavily contaminated with DDTs, HCB and CDs. Cluster analysis was performed on the spatial variation of HCHs, DDTs, HCB, and CDs to group the soil sites in terms of their concentration level. According to the results shown in Table 3, soils from residential area such as G6, G7, G8, G9, G13, G14 were found contaminated by DDTs. In addition, G7 and G13 were also contaminated by HCB. It is worthy to note that G15 (river bank soil) was contaminated by CDs separately. The total OCPs data were classified in a simple manner with results presented as dendrogram. As we can see from Fig. 1, surface soils from residential area such as G7 and G13 were clearly contaminated by OCPs. Concentrations as high as those found in the study area present many problems: like presence of high concentration of contaminants in atmosphere, groundwater, vegetable and other foods, as
Fig. 1. Dendogram showing occurrence of OCPs among 24 sampling sites.
well as in the surface soil. On the basis of Chinese environmental quality standard for soils (GB15618-1995, 1995), the HCHs could be classified as light pollution (50–500 lg kg1) and little pollution (<50 lg kg1) for F and G, respectively. Meanwhile, the DDTs levels of F and G could be defined as little pollution and heavy pollution (>1000 lg kg1), respectively. The situation is more hazardous due to the continuous exposure of the population that lives in the surroundings of the contaminated sites (see Figs. 2 and 3). 3.2. HCHs The concentration of total HCHs (sum of isomers a-HCH + bHCH + c-HCH + d-HCH) in the analyzed samples varied from <0.020 to 595 lg kg1. The concentration of a-HCH ranged between <0.020 and 363 lg kg1, b-HCH between <0.045 and 92.3 lg kg1, c-HCH between <0.021 and 95.7 lg kg1, and those of d-HCH between <0.026 and 44.0 lg kg1. Technical HCH is a mixture of a – (67%), b – (10%), c – (15%), and d – (8%) HCH. It was banned in China in the mid-1980s. Afterwards, it was substituted by c-HCH (also named lindane). HCHs were not detected in most of the soil samples from F, except for F9 (595 lg kg1). Percentage distribution of HCH isomers for sample F9 was very similar to technical HCH (Fig. 1). This indicated that technical HCH probably has been in use and/or production in F since it was built in 2000. High HCHs contamination of F9 is likely to be because of the leaking of technical HCH during transportation. However, HCHs were detected in 80.0% of soil samples from G. The concentrations vary from <0.020 to 96.7 lg kg1. The concentrations of b-HCH accounted for 33.4–91.6% of total HCHs. As we know, b-HCH has all chlorines in equatorial positions and the lowest vapor pressure among four HCH isomers. It is the most persistent isomer and tends to accumulate in soil (Toan et al., 2009). The mean percentages of HCH isomers in the surface soils from factory G were as follows: b a > c > d. This is in agreement with
Table 3 Hierarchical cluster analysis on 24 sites with different compounds. Pesticides
Cluster_1
HCHs DDTs HCB CDs
F1, F1, F1, F1,
F2, F2, F2, F2,
F3, F3, F3, F3,
F4, F4, F4, F4,
F5, F5, F5, F5,
F6, F6, F6, F6,
F7, F7, F7, F7,
F8, F8, F8, F8,
G1, G2, G3, G4, G5, G6, G7, G8, G9, G10, G11, G12, G13, G14, G15 F9, G1, G2, G3, G4, G5, G11, G12, G15 G1, G2, G3, G4, G5, G6, G8, G9, G10, G11, G12, G14, G15 F9, G1, G2, G3, G4, G5, G6, G7, G8, G9, G10, G11, G12, G13, G14
Cluster_2
Cluster_3
F9 G6, G7, G8, G9, G13, G14 G7, G13 G15
na G10 F9 na
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Fig. 2. Percentage distribution of four HCH isomers in surface soil samples from F and G.
Fig. 3. Percentage distribution of DDTs in surface soil samples from F and G.
data reported in soil samples from typical contaminated industrial sites (Yang et al., 2009). It suggested that the technical HCH had not been in production from a quiet long time in G. The ratio of a-HCH/c-HCH is often used as indicators of recent c-HCH input into the environment; low ratios, particularly below one, indicate recent input (Abhilash and Singh, 2008). In the present study, the a-HCH/c-HCH ratio of F9 was 3.79, which was close to the ratio in technical HCH (4–7). It confirmed that technical HCH probably was still in use and/or production in F. However, the average a-HCH/c-HCH ratio of G was 1.42, indicating that HCHs at G was like those from the historically produced decades ago. 3.3. DDTs Technical DDT was first used to control disease-spreading insects and then as a multipurpose insecticide (Wang et al., 2008). The production of DDT in China began in the early 1950s, more than 0.4 million tons of technical DDT were used before it was banned for agricultural application in China in 1983. However, China is still producing DDT for export for malaria control and for domestic use in dicofol production (Qiu et al., 2005). DDTs compounds were detected in all surface soil samples except for F9, ranging from 0.178 to 1980 lg kg1 for o,p0 -DDE, 0.31–6890 lg kg1 for p,p0 -DDE, <0.013–991 lg kg1 for o,p0 -DDD,
<0.014–3460 lg kg1 for p,p0 -DDD, <0.024–7840 lg kg1 for o,p0 DDT, and <0.051–50 400 lg kg1 for p,p0 -DDT. DDTs thus show the largest concentration range among the measured OCPs. Technical DDT is typically composed of 77.1% p,p0 -DDT, 14.9% o,p0 -DDT, 4% p,p0 -DDE, and some other trace impurities (Zhu et al., 2005). The relative abundance of DDT and its metabolite isomers can be used to distinguish between fresh (p,p0 -DDT/p,p0 DDE > 1) and aged (p,p0 -DDT/p,p0 -DDE < 1) sources (Li et al., 2009). The average p,p0 -DDT/p,p0 -DDE ratio of F was 0.51, indicating no fresh DDT inputs. However, the average p,p0 -DDT/p,p0 -DDE ratio of G was 2.10 (ranging from 0.28 to 10.7), suggesting the potential use of DDT in this region. The ratios of o,p0 -DDT/p,p0 -DDT can be used to distinguish technical DDT from ‘‘dicofol-type DDT” (Liu et al., 2009). The ratios in technical DDT and in dicofol were 0.2–0.26 and 1.3–9.3 (Qiu et al., 2005), respectively. However, in this study, the o,p0 -DDT/ p,p0 -DDT ratios were 0.1–0.5 (mean, 0.13), 0.1–2.3 (mean, 0.56) in F and G, respectively. Thus, the historical use of technical DDT may contribute to the surface soils from these two pesticide factories. Meanwhile, the ratios found in eight samples from G were much greater than 0.26, because G is a manufacturer of dicofol in China. The results were consistent with reported data on air samples from this region (Qiu et al., 2004). It might be another piece of evidence supporting dicofol as a main DDT origin.
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3.4. HCB HCB is highly persistent in the environment. The global picture of HCB emissions is available, but potential sources of HCB in developing countries are still not clear (Bailey, 2001). It is worthy to note that HCB has never been registered as a pesticide in China. The total production of HCB from 1988 to 2003 was about 66 000 tones in China, and more than 95% of HCB was used for producing pentachlorophenol (PCP) and pentachlorophenol sodium (Na-PCP). HCB also can be released as a byproduct of chlorination processes in a pesticide production. The concentrations of HCB in surface soils were ranging from 0.08 to 194 lg kg1 (mean, 22.3 lg kg1) in F and from 0.15 to 113 lg kg1 (mean, 21.6 lg kg1) in G. The average concentrations of HCB detected in soils from river bank, roadside, and vegetable plot were 1.92, 0.788, and 0.637 lg kg1, respectively. These levels are comparable or lower than those in soils from fallow land (1.86 ± 1.21 lg kg1), tree land (5.13 ± 3.4 lg kg1), and paddy field (3.76 ± 2.27 lg kg1) in Taihu Lake region (Wang et al., 2007), and urban soils from Katowice Poland (6.4 ± 9.6 lg kg1) (Falandysz et al., 2001). The results indicate wind dispersion, volatilization and subsequent redeposition by precipitation of pesticides containing HCB contribute to the HCB contamination in these soil samples (Tao et al., 2005). HCB from residential area and factory gate soils shows high contamination, with the average concentrations of 47.2 and 112.2 lg kg1, respectively. This is the highest yet reported HCB level in soils. Application of PCP, NaPCP, quintozene, technical HCH, and chlorothalonil (Bailey, 2001; Gouin et al., 2008) may also introduce HCB to the environment. As most of the chlorothalonil products on the market in China are imported or originated from the UK (Liu et al., 2009), the production, transportation, and use of PCP, Na-PCP, technical HCH, and quintozene were assumed as the current HCB sources. Further investigation was needed to clear the relationship between HCB and these pesticides. 3.5. CDs Technical chlordane is a mixture of over 140 different components. It is generally used as insecticide, herbicide, and termiticide, and is still being used against termites in China with over 200 tones per year input recently (Xu et al., 2005). Average chlordane concentrations were in the range of <0.033– 0.972 lg kg1 in other sites of soils, except for 8.43 lg kg1 for river bank soils, which suggest that high chlordane contamination in the river bank soils. The trans-/cis- chlordane ratio is generally used for understanding the emission history and degradability of chlordane (Wang et al., 2008). The ratio in technical chlordane mixture is 1.17– 1.41 (Shen et al., 2005; Hinckley et al., 1990) considering that trans-chlordane is generally more volatile than cis-chlordane. However, the trans-/cis- chlordane ratio was 1.84 in river bank soils, which was similar to the ratio in technical chlordane. This could be attributed to the dumping of chlordane containing hazardous materials on the river bank. Water and sediment in this area need further study. 4. Conclusions From the discussion, one may conclude that surface soils from F and G were contaminated with HCHs, DDTs, HCB, and chlordane. Among these pesticides, b-HCH and p,p0 -DDT were the two dominant substances. The HCB concentration amounts to 194 lg kg1, the highest yet reported in soils. The ratios of a-HCH/c-HCH, o,p0 -DDT/p,p0 -DDT, and trans-/cis- chlordane in some soil samples
are similar to their technical products in the study area. These are indicative of the aged HCHs and the lack of hazardous waste management practices of the pesticide production and transportation. On the basis of GB 15618-1995, the HCHs could be classified as light pollution and little pollution for F and G, whereas DDTs levels of F and G could be defined as little pollution and heavy pollution, respectively. All the concentrations found in the soil, especially in the residential area, could cause long-term eco-toxicological damage. Therefore, on-site remediation technologies are urgently needed to eliminate OCPs contamination in the study area. Moreover, the best available techniques/best environmental practices (BAT/BEP) should be applied in these factories with the national implementation of the Stockholm Convention. Acknowledgments This study was supported by the National Basic Research Program of China (No. 2009CB421602). We are greatly in debt to the two anonymous reviewers for their pertinent and constructive comments. References Abhilash, P.C., Singh, N., 2008. Distribution of hexachlorocyclohexane isomers in soil samples from a small scale industrial area of Lucknow, North India, associated with lindane production. Chemosphere 73, 1011–1015. Bailey, R.E., 2001. Global hexachlorobenzene emissions. Chemosphere 43, 167–182. Cao, H.Y., Liang, T., Tao, S., Zhang, C.S., 2007. Simulating the temporal changes of OCP pollution in Hangzhou, China. Chemosphere 67, 1335–1345. Falandysz, J., Brudnowska, B., Kawano, M., Wakimoto, T., 2001. Polychlorinated biphenyls and organochlorine pesticides in soils from the southern part of Poland. Archives of Environmental Contamination and Toxicology 40, 173–178. GB15618-1995, 1995. General administration of quality supervision, inspection and quarantine: quality standard for soil environment. Gouin, T., Wania, F., Ruepert, C., Castillo, L.E., 2008. Field testing passive air samplers for current use pesticides in a tropical environment. Environmental Science & Technology 42, 6625–6630. Hao, H.T., Sun, B., Zhao, Z.H., 2008. Effect of land use change from paddy to vegetable field on the residues of organochlorine pesticides in soils. Environmental Pollution 156, 1046–1052. Hinckley, D.A., Bidleman, T.F., Foreman, W.T., Tuschall, J.R., 1990. Determination of vapor pressures for nonpolar and semipolar organic compounds from gas chromatographic retention data. Journal of Chemical & Engineering Data 35, 232–237. Holoubek, I., Dusek, L., Sanka, M., Hofman, J., Cupr, P., Jarkovsky, J., Zbiral, J., Klanova, J., in press. Soil burdens of persistent organic pollutants – their levels, fate and risk. Part I. Variation of concentration ranges according to different soil uses and locations. Environmental Pollution. doi:10.1016/j.envpol.2009.05.031. Jiang, Y.F., Wang, X.T., Jia, Y., Wang, F., Wu, M.H., Sheng, G.Y., Fu, J.M., in press. Occurrence, distribution and possible sources of organochlorine pesticides in agricultural soil of Shanghai, China. Journal of Hazardous Materials. doi:10.1016/j.jhazmat.2009.05.082. Kretchik, J.T., 2002. Persistent organic pollutants (POPs). Chemical Health and Safety 9, 35. Li, Y.M., Zhang, Q.H., Ji, D.S., Wang, T., Wang, Y.W., Wang, P., Ding, L., Jiang, G.B., 2009. Levels and vertical distributions of PCBs, PBDEs, and OCPs in the atmospheric boundary layer: observation from the Beijing 325-m meteorological tower. Environmental Science & Technology 43, 1030–1035. Liu, X., Zhang, G., Li, J., Yu, L.L., Xu, Y., Li, X.D., Kobara, Y., Jones, K.C., 2009. Seasonal patterns and current sources of DDTs, chlordanes, hexachlorobenzene, and endosulfan in the atmosphere of 37 Chinese cities. Environmental Science & Technology 43, 1316–1321. Qiu, X.H., Zhu, T., Li, J., Pan, H.S., Li, Q.L., Miao, G.F., Gong, J.C., 2004. Organochlorine pesticides in the air around Taihu Lake, China. Environmental Science & Technology 38, 1368–1374. Qiu, X.H., Zhu, T., Yao, B., Hu, J.X., Hu, S.W., 2005. Contribution of dicofol to the current DDT pollution in China. Environmental Science & Technology 39, 4385– 4390. Shen, L., Wania, F., Lei, Y.D., Teixeira, C., Muir, D.C.G., Bidleman, T.F., 2005. Atmospheric distribution and long-range transport behavior of organochlorine pesticides in North America. Environmental Science & Technology 39, 409–420. Tao, S., Xu, F.L., Wang, X.J., Liu, W.X., Gong, Z.M., Fang, J.Y., Zhu, L.Z., Luo, Y.M., 2005. Organochlorine pesticides in agricultural soil and vegetables from Tianjin, China. Environmental Science & Technology 39, 2494–2499. Toan, V.D., Thao, V.D., Walder, J., Ha, C.T., 2009. Residue, temporal trend and half-life time of selected organochlorine pesticides (OCPs) in surface soils from Bacninh, Vietnam. Bulletin of Environmental Contamination and Toxicology 82, 516– 521.
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Organochlorine pesticides contamination in surface soils from two pesticide factories in Southeast China Lifei Zhang, Liang Dong, Shuangxin Shi, Li Zhou, Ting Zhang, Yeru Huang * State Environmental Protection Key Laboratory of Dioxin Pollution Control, National Research Center for Environmental Analysis and Measurement, No. 1 Yuhui Nanlu, Chaoyang District, Beijing 100029, China
a r t i c l e
i n f o
Article history: Received 18 May 2009 Received in revised form 11 August 2009 Accepted 27 August 2009 Available online 20 September 2009 Keywords: Organochlorine pesticides Soil Contamination Southeast China
a b s t r a c t The present article attempts to investigate organochlorine pesticides’ (OCPs) contamination in soils from polluted sites and to assess the soil quality in the study area. HCHs and eight other persistent organic pollutants (POPs) pesticides were studied in surface soil samples collected from a new (F) and an old (G) pesticide factory in Southeast China. According to the measured results, surface soils from F and G were contaminated with HCHs, DDTs, HCB, and chlordane, with b-HCH and p,p0 -DDT being the two dominant substances. The total OCPs concentrations of surface soils from F and G were 0.84 and 166 mg kg1 respectively. Cluster analysis was performed to group the soil sites in terms of their total OCPs contamination levels. The ratios of a-HCH/c-HCH, o,p0 -DDT/p,p0 -DDT, and trans-/cis- chlordane in some of the soil samples are similar to their technical products in the study area which indicates the lack of hazardous waste management practices of the pesticide production and transportation. According to GB 156181995, the HCHs could be classified as light pollution and little pollution for F and G, whereas DDTs levels of F and G could be defined as little pollution and heavy pollution, respectively. This study indicates that surface soils, especially residential area soils from F and G were facing varying degrees of pollutions. The situation is more hazardous due to the continuous exposure of the population that lives in the surroundings. Therefore, on-site remediation technologies and the best available techniques/best environmental practices (BAT/BEP) should be carried out on these factories with the national implementation of the Stockholm Convention. Ó 2009 Elsevier Ltd. All rights reserved.
1. Introduction Organochlorine pesticides (OCPs) are a set of chemicals that are toxic, persist in the environment for long periods of time, and biomagnify as they move up through the food chain (Kretchik, 2002). They have been linked to adverse effects on human health and animals and were classified to persistent organic pollutants (POPs). A large quantity of OCPs were produced between the 1950s and the 1980s with about 4460 000 t technical HCHs and 435 200 t DDTs (Cao et al., 2007). In 1990, 148 kinds of pesticides, amounting to 226 000 tons, were produced in China, ranking third in the world (Wang et al., 2005). Application of pesticides can improve crop yields for agriculture, but soil adsorption may occur as well, especially for carbon-rich soils (Holoubek et al., in press). These pesticides present a vast history of environmental contamination all over the country, especially in Southeast China (Cao et al., 2007). With the signing of the Stockholm Convention and the development of global monitoring programs, there is an increasing need * Corresponding author. Tel.: +86 10 8466 5753; fax: +86 10 8463 4275. E-mail address: [email protected] (Y. Huang). 0045-6535/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2009.08.055
for developing countries to monitor OCPs in various environmental compartments (Abhilash and Singh, 2008). Recent surveys and monitoring have reported relatively high levels of OCPs in soils from Southeast China (Wang et al., 2005; Cao et al., 2007; Hao et al., 2008). However, assessment on the OCPs in soil is difficult because of the lack of representativeness of data. In this study, two pesticide factories in Southeast China were selected as the typical contamination sites. A total of 24 surface soil samples were collected at five land-use types of soil around these two factories. Organochlorine pesticides, including HCHs and 8 other POPs pesticides were determined to evaluate the extent to which contamination of OCPs varied. The major purpose of this study is to: (1) investigate the concentrations, compositions and distributions of OCPs in two pesticide factories in Southeast China, and (2) to assess the soil quality and to evaluate the potential risks to human health and environmental safety in this area. Furthermore, the remediation methods for those contaminated sites would also be discussed. This paper presents the current status of OCPs residues on contamination sites. The dataset generated will enrich the knowledge on contamination sites such as pesticide factories.
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2. Materials and methods 2.1. Chemicals and reagents A mixed stock standard solution of OCPs containing a-HCH, bHCH, c-HCH, d-HCH, o,p0 -DDE, p,p0 -DDE, o,p0 -DDD, p,p0 -DDD, o,p0 DDT, p,p0 -DDT, hexachlorobenzene, oxy-chlordane, trans-chlordane, cis-chlordane, heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, methoxychlor, and mirex at a concentration of 100 mg L1 was purchased from Chem Service, Inc., USA. The surrogate (13C-p,p0 -DDT) and the internal standard (deuterated phenanthrene, deuterated pyrene, and deuterated chrysene) were purchased from AccuStandard, Inc., USA. Acetone, n-hexane and methylene chloride (for organic residue analysis) were obtained from J.T. Baker, USA.
cleaned up with a Florisil solid phase extraction (SPE) cartridge (1 g, 6 mL, Supelco, USA). After the sample was transferred onto the cartridge, it was then eluted with 12 mL acetone/hexane (2/ 98, v/v). The eluate was concentrated to about 1 mL under a centrifugal vacuum evaporator system (CVE3100, Eyala, Japan). Twenty microlitres of deuterated phenanthrene, deuterated pyrene, and deuterated chrysene mixture standard solution (10 ng lL1) was added to the solution as injection internal standard prior to transferring to a glass microvial for GC injection. 2.4. OCPs determination
Samples were collected in July, 2008 from two pesticide factories, F (32°100 3200 N, 119°360 2400 E) and G (32°220 2300 N, 119°250 3500 E) in Jiangsu Province, in southeast of China. F is a new factory which was built in 2000, whereas G is a famous pesticide factory in Southeast China which was built in the 1950s. A total of 24 surface soil (0–10 cm) samples were collected around the factories with 9 for F and 15 for G. At each site, composite surface soil samples were collected from four locations 2 m apart (200 g each) and thoroughly mixed. Three soil samples were collected from each site. The 24 sampling sites were derived from five different land-use types of soil surrounding F and G (see Table 2).
The determination of OCPs was performed on a Shimadzu GCMS-QP2010 equipped with a fused silica capillary DB-5MS column (30 m 0.25 mm i.d., film thickness: 0.25 lm) using electron ionization with selective ion monitoring mode. High purity (99.99%) helium was used as carrier gas at 0.98 mL/min. The injector, transfer line, and ion source temperature were 250 °C, 260 °C, and 230 °C respectively. The oven temperature program was as follows: initial temperature 70 °C held for 1 min, increased to 180 °C at 20 °C/min, then to 260 °C at 4 °C/min, and to 300 °C at 15 °C/min, held for 6 min. Two microlitres of each sample was injected in the spilt mode with 1:14.1. Injection internal standards were used for quantification. OCPs measured in soils include four HCH isomers, six DDT homologues, HCB, oxy-chlordane, trans-chlordane, cischlordane, heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, methoxychlor, and mirex. Concentrations of RHCHs, RDDTs and RCDs were the R of the four HCH isomers, six DDT homologues and three chlordane (oxy-chlordane, trans-chlordane, cis-chlordane), respectively.
2.3. Sample extraction and cleanup
2.5. Quality control
Each fully mixed soil sample was air-dried, sieved through a 1 mm mesh, and ground before analysis. After 20 lL of 13C-p,p0 DDT (5 ng lL1) added as surrogate and 2.0 g active Cu added to eliminate element sulfur, 5.0 g soil was extracted by accelerated solvent extraction (ASE 300, Dionex, USA), using 1:1 methylene chloride/acetone as extracting solvent at 100 °C. The extract obtained was concentrated to approximately 1 mL and further
The detection limit ranged from 0.014 to 0.178 lg kg1 for OCPs. The method blanks showed no detectable target compounds. Surrogate was added to all the soil samples. The recoveries of 13Cp,p0 -DDT by this method fell within the range of 75–125%. All reported values were corrected by the field blanks and surrogate recovery. Quality control was performed on the analysis of Standard Reference MaterialÒ 1944 (SRM 1944, New York/New Jersey
2.2. Soil sampling
Table 1 Method detection limit (MDL) and comparison between determined and SRM 1944 certified values (lg kg1) (nd: not detected; na: not available). Name
MDL
Determined value
Certified value
Name
MDL
Determined value
Certified value
a-HCH
0.020 0.019 0.045 0.021 0.026 0.031 0.041 0.033 0.178 0.088 0.034
nd 5.84 ± 0.40 nd nd nd nd nd nd nd nd 22 ± 4.5
2.0 ± 0.3 6.03 ± 0.35 na na na na na na na na 8±2
o,p0 -DDE cis-Chlordane p,p0 -DDE Dieldrin o,p0 -DDD Endrin p,p0 -DDD o,p0 -DDT p,p0 -DDT Methoxychlor Mirex
0.014 0.033 0.028 0.068 0.013 0.101 0.014 0.024 0.051 0.048 0.022
17 ± 3.9 14.1 ± 2.4 108 ± 16 nd 45.8 ± 12 nd 118 ± 14 107 ± 94 128 ± 52 nd nd
19 ± 3 16.51 ± 0.83 86 ± 12 na 38 ± 8 na 108 ± 16 na 119 ± 11 na na
HCB b-HCH c-HCH d-HCH Heptachlor Aldrin Heptachlor epoxide A Oxy-chlordane Heptachlor epoxide B trans-Chlordane
Table 2 Organochlorine pesticides concentration (lg kg1) in surface soils from F and G. Sites type
Sites
RHCHs
RDDTs
HCB
RCDs
OCPs
River bank Roadside Vegetable plot Residential area Factory gate
G1, G2, G3, G15 F1, F2, F3, F4, F5, F6, F7, F8, G12 G4, G5, G11 G6, G7, G8, G9, G13, G14 F9, G10
2.88 ± 3.1 0 1.64 ± 2.8 34.9 ± 33 313 ± 399
2339 ± 1620 22.8 ± 51 661 ± 478 14,329 ± 5510 33,748 ± 47,730
1.92 ± 1.7 0.788 ± 1.4 0.637 ± 0.5 47.2 ± 45 112.2 ± 116
8.43 ± 15.0 0 0.081 ± 0.14 0.972 ± 1.07 0.335 ± 0.47
2352 ± 1167 23.6 ± 11 663.7 ± 330 14,412 ± 7150 34,173 ± 16,800
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Waterway Sediment). The average values of OCPs determined and the standard deviation of triplicate samples by this method are in Table 1. 2.6. Statistical analysis Conventional statistical analysis and cluster analysis were carried out using SPSS 16.0. 3. Results and discussion 3.1. OCPs concentration and soil quality assessment Analysis results showed that most of the OCPs were found in samples except heptachlor, heptachlor epoxide, methoxychlor, aldrin, dieldrin, endrin, and mirex. In general, the total OCPs concentrations of surface soils from F and G were 0.84 and 166 mg kg1 respectively. The total OCPs concentration of G is approximately 200 times as much as that of F, since it has more than 30 years history than F. In another way, plant uptake from the polluted site could reduce the soil contamination when paralleling F with G. However, on-site remediation technologies are urgently needed to eliminate OCPs contamination in the study area. The average concentrations of RHCHs, RDDTs, RCDs, and HCB of F and G were 66.1, 5.14, <0.033, 22.3 lg kg1 and 17.1, 10,998, 2.70, 21.6 lg kg1, respectively. They were much lower than the average concentrations of RHCHs (53–99 mg kg1) and RDDTs (3800– 7300 mg kg1) found in some reported heavily contaminated sites (Villa et al., 2006; Abhilash and Singh, 2008). However, the total HCHs at both factories and total DDTs at F were comparable or slightly higher than surface soils from Bacninh, Vietnam (Toan et al., 2009), but much higher than agricultural soil of Shanghai (Jiang et al., in press). Samples were grouped according to the soils of river bank, roadside, vegetable plot, residential area, and factory gate. The concentrations of RHCHs, RDDTs, HCB, RCDs, and total OCPs in various soils collected from F and G are presented in Table 2, as mean ± standard deviation. The total OCPs concentrations in soil samples were as follows: factory gate > residential area river bank > vegetable plot > roadside. Therefore, the OCPs concentration in factory gate soils were found not significantly (p < 0.05) different from residential area soils, suggesting that residential area soils were similar to factory gate soils, and were heavily contaminated with DDTs, HCB and CDs. Cluster analysis was performed on the spatial variation of HCHs, DDTs, HCB, and CDs to group the soil sites in terms of their concentration level. According to the results shown in Table 3, soils from residential area such as G6, G7, G8, G9, G13, G14 were found contaminated by DDTs. In addition, G7 and G13 were also contaminated by HCB. It is worthy to note that G15 (river bank soil) was contaminated by CDs separately. The total OCPs data were classified in a simple manner with results presented as dendrogram. As we can see from Fig. 1, surface soils from residential area such as G7 and G13 were clearly contaminated by OCPs. Concentrations as high as those found in the study area present many problems: like presence of high concentration of contaminants in atmosphere, groundwater, vegetable and other foods, as
Fig. 1. Dendogram showing occurrence of OCPs among 24 sampling sites.
well as in the surface soil. On the basis of Chinese environmental quality standard for soils (GB15618-1995, 1995), the HCHs could be classified as light pollution (50–500 lg kg1) and little pollution (<50 lg kg1) for F and G, respectively. Meanwhile, the DDTs levels of F and G could be defined as little pollution and heavy pollution (>1000 lg kg1), respectively. The situation is more hazardous due to the continuous exposure of the population that lives in the surroundings of the contaminated sites (see Figs. 2 and 3). 3.2. HCHs The concentration of total HCHs (sum of isomers a-HCH + bHCH + c-HCH + d-HCH) in the analyzed samples varied from <0.020 to 595 lg kg1. The concentration of a-HCH ranged between <0.020 and 363 lg kg1, b-HCH between <0.045 and 92.3 lg kg1, c-HCH between <0.021 and 95.7 lg kg1, and those of d-HCH between <0.026 and 44.0 lg kg1. Technical HCH is a mixture of a – (67%), b – (10%), c – (15%), and d – (8%) HCH. It was banned in China in the mid-1980s. Afterwards, it was substituted by c-HCH (also named lindane). HCHs were not detected in most of the soil samples from F, except for F9 (595 lg kg1). Percentage distribution of HCH isomers for sample F9 was very similar to technical HCH (Fig. 1). This indicated that technical HCH probably has been in use and/or production in F since it was built in 2000. High HCHs contamination of F9 is likely to be because of the leaking of technical HCH during transportation. However, HCHs were detected in 80.0% of soil samples from G. The concentrations vary from <0.020 to 96.7 lg kg1. The concentrations of b-HCH accounted for 33.4–91.6% of total HCHs. As we know, b-HCH has all chlorines in equatorial positions and the lowest vapor pressure among four HCH isomers. It is the most persistent isomer and tends to accumulate in soil (Toan et al., 2009). The mean percentages of HCH isomers in the surface soils from factory G were as follows: b a > c > d. This is in agreement with
Table 3 Hierarchical cluster analysis on 24 sites with different compounds. Pesticides
Cluster_1
HCHs DDTs HCB CDs
F1, F1, F1, F1,
F2, F2, F2, F2,
F3, F3, F3, F3,
F4, F4, F4, F4,
F5, F5, F5, F5,
F6, F6, F6, F6,
F7, F7, F7, F7,
F8, F8, F8, F8,
G1, G2, G3, G4, G5, G6, G7, G8, G9, G10, G11, G12, G13, G14, G15 F9, G1, G2, G3, G4, G5, G11, G12, G15 G1, G2, G3, G4, G5, G6, G8, G9, G10, G11, G12, G14, G15 F9, G1, G2, G3, G4, G5, G6, G7, G8, G9, G10, G11, G12, G13, G14
Cluster_2
Cluster_3
F9 G6, G7, G8, G9, G13, G14 G7, G13 G15
na G10 F9 na
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Fig. 2. Percentage distribution of four HCH isomers in surface soil samples from F and G.
Fig. 3. Percentage distribution of DDTs in surface soil samples from F and G.
data reported in soil samples from typical contaminated industrial sites (Yang et al., 2009). It suggested that the technical HCH had not been in production from a quiet long time in G. The ratio of a-HCH/c-HCH is often used as indicators of recent c-HCH input into the environment; low ratios, particularly below one, indicate recent input (Abhilash and Singh, 2008). In the present study, the a-HCH/c-HCH ratio of F9 was 3.79, which was close to the ratio in technical HCH (4–7). It confirmed that technical HCH probably was still in use and/or production in F. However, the average a-HCH/c-HCH ratio of G was 1.42, indicating that HCHs at G was like those from the historically produced decades ago. 3.3. DDTs Technical DDT was first used to control disease-spreading insects and then as a multipurpose insecticide (Wang et al., 2008). The production of DDT in China began in the early 1950s, more than 0.4 million tons of technical DDT were used before it was banned for agricultural application in China in 1983. However, China is still producing DDT for export for malaria control and for domestic use in dicofol production (Qiu et al., 2005). DDTs compounds were detected in all surface soil samples except for F9, ranging from 0.178 to 1980 lg kg1 for o,p0 -DDE, 0.31–6890 lg kg1 for p,p0 -DDE, <0.013–991 lg kg1 for o,p0 -DDD,
<0.014–3460 lg kg1 for p,p0 -DDD, <0.024–7840 lg kg1 for o,p0 DDT, and <0.051–50 400 lg kg1 for p,p0 -DDT. DDTs thus show the largest concentration range among the measured OCPs. Technical DDT is typically composed of 77.1% p,p0 -DDT, 14.9% o,p0 -DDT, 4% p,p0 -DDE, and some other trace impurities (Zhu et al., 2005). The relative abundance of DDT and its metabolite isomers can be used to distinguish between fresh (p,p0 -DDT/p,p0 DDE > 1) and aged (p,p0 -DDT/p,p0 -DDE < 1) sources (Li et al., 2009). The average p,p0 -DDT/p,p0 -DDE ratio of F was 0.51, indicating no fresh DDT inputs. However, the average p,p0 -DDT/p,p0 -DDE ratio of G was 2.10 (ranging from 0.28 to 10.7), suggesting the potential use of DDT in this region. The ratios of o,p0 -DDT/p,p0 -DDT can be used to distinguish technical DDT from ‘‘dicofol-type DDT” (Liu et al., 2009). The ratios in technical DDT and in dicofol were 0.2–0.26 and 1.3–9.3 (Qiu et al., 2005), respectively. However, in this study, the o,p0 -DDT/ p,p0 -DDT ratios were 0.1–0.5 (mean, 0.13), 0.1–2.3 (mean, 0.56) in F and G, respectively. Thus, the historical use of technical DDT may contribute to the surface soils from these two pesticide factories. Meanwhile, the ratios found in eight samples from G were much greater than 0.26, because G is a manufacturer of dicofol in China. The results were consistent with reported data on air samples from this region (Qiu et al., 2004). It might be another piece of evidence supporting dicofol as a main DDT origin.
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3.4. HCB HCB is highly persistent in the environment. The global picture of HCB emissions is available, but potential sources of HCB in developing countries are still not clear (Bailey, 2001). It is worthy to note that HCB has never been registered as a pesticide in China. The total production of HCB from 1988 to 2003 was about 66 000 tones in China, and more than 95% of HCB was used for producing pentachlorophenol (PCP) and pentachlorophenol sodium (Na-PCP). HCB also can be released as a byproduct of chlorination processes in a pesticide production. The concentrations of HCB in surface soils were ranging from 0.08 to 194 lg kg1 (mean, 22.3 lg kg1) in F and from 0.15 to 113 lg kg1 (mean, 21.6 lg kg1) in G. The average concentrations of HCB detected in soils from river bank, roadside, and vegetable plot were 1.92, 0.788, and 0.637 lg kg1, respectively. These levels are comparable or lower than those in soils from fallow land (1.86 ± 1.21 lg kg1), tree land (5.13 ± 3.4 lg kg1), and paddy field (3.76 ± 2.27 lg kg1) in Taihu Lake region (Wang et al., 2007), and urban soils from Katowice Poland (6.4 ± 9.6 lg kg1) (Falandysz et al., 2001). The results indicate wind dispersion, volatilization and subsequent redeposition by precipitation of pesticides containing HCB contribute to the HCB contamination in these soil samples (Tao et al., 2005). HCB from residential area and factory gate soils shows high contamination, with the average concentrations of 47.2 and 112.2 lg kg1, respectively. This is the highest yet reported HCB level in soils. Application of PCP, NaPCP, quintozene, technical HCH, and chlorothalonil (Bailey, 2001; Gouin et al., 2008) may also introduce HCB to the environment. As most of the chlorothalonil products on the market in China are imported or originated from the UK (Liu et al., 2009), the production, transportation, and use of PCP, Na-PCP, technical HCH, and quintozene were assumed as the current HCB sources. Further investigation was needed to clear the relationship between HCB and these pesticides. 3.5. CDs Technical chlordane is a mixture of over 140 different components. It is generally used as insecticide, herbicide, and termiticide, and is still being used against termites in China with over 200 tones per year input recently (Xu et al., 2005). Average chlordane concentrations were in the range of <0.033– 0.972 lg kg1 in other sites of soils, except for 8.43 lg kg1 for river bank soils, which suggest that high chlordane contamination in the river bank soils. The trans-/cis- chlordane ratio is generally used for understanding the emission history and degradability of chlordane (Wang et al., 2008). The ratio in technical chlordane mixture is 1.17– 1.41 (Shen et al., 2005; Hinckley et al., 1990) considering that trans-chlordane is generally more volatile than cis-chlordane. However, the trans-/cis- chlordane ratio was 1.84 in river bank soils, which was similar to the ratio in technical chlordane. This could be attributed to the dumping of chlordane containing hazardous materials on the river bank. Water and sediment in this area need further study. 4. Conclusions From the discussion, one may conclude that surface soils from F and G were contaminated with HCHs, DDTs, HCB, and chlordane. Among these pesticides, b-HCH and p,p0 -DDT were the two dominant substances. The HCB concentration amounts to 194 lg kg1, the highest yet reported in soils. The ratios of a-HCH/c-HCH, o,p0 -DDT/p,p0 -DDT, and trans-/cis- chlordane in some soil samples
are similar to their technical products in the study area. These are indicative of the aged HCHs and the lack of hazardous waste management practices of the pesticide production and transportation. On the basis of GB 15618-1995, the HCHs could be classified as light pollution and little pollution for F and G, whereas DDTs levels of F and G could be defined as little pollution and heavy pollution, respectively. All the concentrations found in the soil, especially in the residential area, could cause long-term eco-toxicological damage. Therefore, on-site remediation technologies are urgently needed to eliminate OCPs contamination in the study area. Moreover, the best available techniques/best environmental practices (BAT/BEP) should be applied in these factories with the national implementation of the Stockholm Convention. Acknowledgments This study was supported by the National Basic Research Program of China (No. 2009CB421602). We are greatly in debt to the two anonymous reviewers for their pertinent and constructive comments. References Abhilash, P.C., Singh, N., 2008. Distribution of hexachlorocyclohexane isomers in soil samples from a small scale industrial area of Lucknow, North India, associated with lindane production. Chemosphere 73, 1011–1015. Bailey, R.E., 2001. Global hexachlorobenzene emissions. Chemosphere 43, 167–182. Cao, H.Y., Liang, T., Tao, S., Zhang, C.S., 2007. Simulating the temporal changes of OCP pollution in Hangzhou, China. Chemosphere 67, 1335–1345. Falandysz, J., Brudnowska, B., Kawano, M., Wakimoto, T., 2001. Polychlorinated biphenyls and organochlorine pesticides in soils from the southern part of Poland. Archives of Environmental Contamination and Toxicology 40, 173–178. GB15618-1995, 1995. General administration of quality supervision, inspection and quarantine: quality standard for soil environment. Gouin, T., Wania, F., Ruepert, C., Castillo, L.E., 2008. Field testing passive air samplers for current use pesticides in a tropical environment. Environmental Science & Technology 42, 6625–6630. Hao, H.T., Sun, B., Zhao, Z.H., 2008. Effect of land use change from paddy to vegetable field on the residues of organochlorine pesticides in soils. Environmental Pollution 156, 1046–1052. Hinckley, D.A., Bidleman, T.F., Foreman, W.T., Tuschall, J.R., 1990. Determination of vapor pressures for nonpolar and semipolar organic compounds from gas chromatographic retention data. Journal of Chemical & Engineering Data 35, 232–237. Holoubek, I., Dusek, L., Sanka, M., Hofman, J., Cupr, P., Jarkovsky, J., Zbiral, J., Klanova, J., in press. Soil burdens of persistent organic pollutants – their levels, fate and risk. Part I. Variation of concentration ranges according to different soil uses and locations. Environmental Pollution. doi:10.1016/j.envpol.2009.05.031. Jiang, Y.F., Wang, X.T., Jia, Y., Wang, F., Wu, M.H., Sheng, G.Y., Fu, J.M., in press. Occurrence, distribution and possible sources of organochlorine pesticides in agricultural soil of Shanghai, China. Journal of Hazardous Materials. doi:10.1016/j.jhazmat.2009.05.082. Kretchik, J.T., 2002. Persistent organic pollutants (POPs). Chemical Health and Safety 9, 35. Li, Y.M., Zhang, Q.H., Ji, D.S., Wang, T., Wang, Y.W., Wang, P., Ding, L., Jiang, G.B., 2009. Levels and vertical distributions of PCBs, PBDEs, and OCPs in the atmospheric boundary layer: observation from the Beijing 325-m meteorological tower. Environmental Science & Technology 43, 1030–1035. Liu, X., Zhang, G., Li, J., Yu, L.L., Xu, Y., Li, X.D., Kobara, Y., Jones, K.C., 2009. Seasonal patterns and current sources of DDTs, chlordanes, hexachlorobenzene, and endosulfan in the atmosphere of 37 Chinese cities. Environmental Science & Technology 43, 1316–1321. Qiu, X.H., Zhu, T., Li, J., Pan, H.S., Li, Q.L., Miao, G.F., Gong, J.C., 2004. Organochlorine pesticides in the air around Taihu Lake, China. Environmental Science & Technology 38, 1368–1374. Qiu, X.H., Zhu, T., Yao, B., Hu, J.X., Hu, S.W., 2005. Contribution of dicofol to the current DDT pollution in China. Environmental Science & Technology 39, 4385– 4390. Shen, L., Wania, F., Lei, Y.D., Teixeira, C., Muir, D.C.G., Bidleman, T.F., 2005. Atmospheric distribution and long-range transport behavior of organochlorine pesticides in North America. Environmental Science & Technology 39, 409–420. Tao, S., Xu, F.L., Wang, X.J., Liu, W.X., Gong, Z.M., Fang, J.Y., Zhu, L.Z., Luo, Y.M., 2005. Organochlorine pesticides in agricultural soil and vegetables from Tianjin, China. Environmental Science & Technology 39, 2494–2499. Toan, V.D., Thao, V.D., Walder, J., Ha, C.T., 2009. Residue, temporal trend and half-life time of selected organochlorine pesticides (OCPs) in surface soils from Bacninh, Vietnam. Bulletin of Environmental Contamination and Toxicology 82, 516– 521.
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