Contribution of Dicofol to the Current DDT Pollution in China

commercially available formulated dicofol in China were collected in 2003 to measure the impurities of DDT related compounds (DDTs). The o,p′-DDT/p ...
0 downloads 0 Views 204KB Size
Download PDF
Environ. Sci. Technol. 2005, 39, 4385-4390

Contribution of Dicofol to the Current DDT Pollution in China X I N G H U A Q I U , † T O N G Z H U , * ,† B O Y A O , † JIANXIN HU,† AND SHAOWEN HU‡ State Key Joint Laboratory for Environmental Simulation & Pollution Control, College of Environmental Sciences, Peking University, Beijing 100871, China, and Department of Applied Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China

High DDT concentrations and o,p′-DDT/p,p′-DDT ratios observed in the air over Taihu Lake, a lake near Shanghai, China, led us to suggest that current use of dicofol in the area north of the lake was the main source of the measured DDTs. To examine this hypothesis, samples of commercially available formulated dicofol in China were collected in 2003 to measure the impurities of DDT related compounds (DDTs). The o,p′-DDT/p,p′-DDT ratio in the samples was 7.0, close to the observed value in the air over Taihu Lake. Average contents of o,p′-DDT, p,p′-ClDDT, o,p′-DDE, and p,p′-DDT in the samples were 114, 69, 44, and 17 g per kg dicofol, respectively. On the basis of a production and distribution survey, total input of DDTs to the environment from the dicofol use in China was estimated to be 8770 t between 1988 and 2002. “Dicofol type DDT pollution”, defined as DDT pollution caused by dicofol use and characterized with high o,p′-DDT/p,p′-DDT ratio, might be serious in China, especially in southern and eastern China. The conversion of p,p′-Cl-DDT to p,p′DDE can lead to high p,p′-DDE/p,p′-DDT ratio and could mislead the evaluation of p,p′-DDT resident time in the environment. Therefore, more studies on p,p′-Cl-DDT in the environment are needed.

Introduction The production of DDT in China began in the early 1950s; by 1983, when the Chinese government banned the use of this pesticide, a total of 270 000 t DDT had been produced (1). China is still producing DDT for export for malaria control and for domestic use in dicofol production. After technical DDT was banned for almost two decades, no apparent decline in the concentrations of DDT related compounds (DDTs) in the environment has been observed in China (2); this indicates the existence of currently unknown sources of DDTs besides residues of technical DDT used in agriculture before 1983. Air samples collected over Taihu Lake during the summer of 2002 showed very high concentrations of DDTs and high o,p′-DDT/ p,p′-DDT concentration ratios (6.3 ( 3.7), suggesting dicofol was a possible DDT source (3). High levels of o,p′-DDT have also been found in dicofol in other countries resulting in elevated DDTs in environment (e.g., refs 4 and 5). * Corresponding author phone: 86(10)62754789; fax: 86(10)62751927; e-mail: [email protected]. † State Key Joint Laboratory for Environmental Simulation & Pollution Control. ‡ Department of Applied Chemistry. 10.1021/es050342a CCC: $30.25 Published on Web 05/05/2005

 2005 American Chemical Society

Dicofol, trade name Kelthane, is a nonsystemic acaricide extensively used for controlling mites that damage cotton, fruit trees, and vegetables. Its acaricidal active ingredient is 2,2,2-trichloro-1,1-bis(4-chlorophenyl)ethanol. Dicofol is usually synthesized from technical DDT. During the synthesis reaction, DDT is first chlorinated to an intermediate, ClDDT, followed by hydrolyzing to dicofol (6):

After the synthesis reaction, DDT and Cl-DDT may remain in the dicofol product as impurities. Because of high contents of DDTs (4, 5), dicofol was temporarily banned by the U.S. EPA in 1986 until DDT contents were reduced to less than 0.1% (7). The implementation of the Prohibition Directive 79/117/EEC by European Commissions strictly limited DDT contents in dicofol to less than 0.1% (7) and has successfully reduced DDT contents in dicofol in England (5). The use of dicofol in China was banned on tea plant and vegetables in some regions. Two chemical industry sector standards of the People’s Republic of China, HG3699-2002 and HG3700-2002, require DDT impurity to be no more than 0.5% of technical dicofol or no more than 0.1% of formulated dicofol containing 20% dicofol. These standards were supposed to be implemented on July 1, 2003. However, dicofol productions with impurity of DDTs above these standards are still available in the Chinese market even after that date. Until now, little is known about the DDT impurities in dicofol and the contribution of dicofol use to current DDT pollution in China. Recent environmental measurements have indicated DDT pollution contributed by dicofol in China could be very significant (3). To evaluate the scale of DDT pollution caused by dicofol use in China, commercial samples of formulated dicofol were collected to measure DDT contents, and the information on sales and uses of dicofol were collected through field surveys. This paper reports (i) measured DDT contents in formulated dicofol in the Chinese market and estimates of DDTs brought into the environment by the dicofol use in China in recent years and (ii) spatial distribution of DDT pollution by the dicofol use in China in 2002. On the basis of the finding that p,p′-Cl-DDT can thermally convert to p,p′-DDE during GC analysis, this paper also warns that the environmental concentrations of p,p′-Cl-DDT could be overlooked and p,p′DDE overestimated.

Experimental Section Survey of Formulated Dicofol in the Chinese Market. From the summer of 2003 to early 2004, information on sales and uses of dicofol were collected from selling agents and consumers in seven Chinese provinces where cotton and fruit growing are common agricultural activities. Information on production and sales was also collected from the largest dicofol manufacturer. At the same time, 23 formulated dicofol samples produced by seven manufacturers (named as A, B, C, D, E, F, and G) in 2002 and 2003 were collected directly from the markets in seven provinces. For each sample, 3 mL was transferred from a well-mixed 400-mL formulated dicofol into a 4-mL glass vial with Teflon lined cap, which was then VOL. 39, NO. 12, 2005 / ENVIRONMENTAL SCIENCE & TECHNOLOGY

9

4385

FIGURE 1. HPLC-measured p,p′-Cl-DDT concentrations, GC/MS-measured p,p′-DDE concentrations, and calculated concentration of p,p′DDE in the formulated dicofol samples. wrapped with aluminum foil and sealed in a polythene bag. The samples were stored at below -10 °C until analysis. Reagents. p,p′-DDT (98%), p,p′-DDE (99.5%), and p,p′DDD (99.0%) were from ChemService Inc. (West Chester, PA). o,p′-DDT (97.0%), o,p′-DDE (98.0%), o,p′-DDD (99.5%), and p,p′-dicofol (97.3%) were from Dr. Ehrenstorfer GmbH, Germany. Methanol (HPLC grade) was from the Dikma Company. Water was deionized and then purified and filtered with MilliPore system (Milli-Q Gradient). Following the procedures outlined in ref 8, p,p′-Cl-DDT (1,2,2,2-tetrachloro- 1,1-bis (4-chlorophenyl) ethane) was synthesized from technical DDT and then purified. Melting point at 90-92 °C, NMR (including 1HMR and 13CMR), and mass spectrum were used to identify the product p,p′-ClDDT. HPLC and GC/MS were used to check the purity of the product. HPLC analysis at a detecting wavelength of 254 nm showed that the peak area of p,p′-Cl-DDT accounted for more than 99.5% of the total area from all the peaks. GC/MS analysis showed that peaks of impurities were negligible compared to the peak of p,p′-DDE, which was the thermal degradation product of p,p′-Cl-DDT during the GC analysis. Samples Analysis. Dicofol and p,p′-Cl-DDT are thermally unstable; therefore, HPLC (HP 1050 with UV detector) was used to analyze them in the formulated dicofol samples, using a detecting wavelength of 254 nm and an Inersil C8 column (25 cm × 4.6 mm i.d., 5-µm particle size, Japan). Mixture of methanol/water/acetic acid (75/25/0.2 by volume) was used as mobile phase with a flow rate of 2 mL min-1. The formulated dicofol samples were diluted with methanol by a factor of 100 to measure dicofol and by a factor of 10 to measure p,p′-Cl-DDT. When necessary, acetone was added to remove the emulsion in the diluted samples. Methoxychlor was spiked into the final diluted samples as internal standard with a concentration of 1.1 mg mL-1. For each analysis, 20 µL of diluted sample was injected into HPLC. GC/MS (Finnigan Trace GC/Polaris Q) was used to analyze p,p′- and o,p′- isomers of DDT, DDE, and DDD in the formulated dicofol samples. The samples were diluted by a factor of 104 with n-hexane. When necessary, acetone was added to remove the emulsion in the diluted samples. PCB155 was spiked into the diluted samples as internal standard with a concentration of 100 ng mL-1. One microliter of diluted sample was injected into GC/MS and analyzed with the conditions described in ref 3. 4386

9

ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 39, NO. 12, 2005

Results and Discussion Thermal Degradation of p,p′-Cl-DDT to p,p′-DDE. p,p′-ClDDT was found to thermally decompose to p,p′-DDE under high temperature during GC analysis (9). This means that GC-measured p,p′-DDE concentrations in the dicofol samples could come from p,p′-DDE in the dicofol formulations and thermal decomposition from p,p′-Cl-DDT during GC analysis. To quantify the level of p,p′-DDE in dicofol, the relationship between p,p′-Cl-DDT and its thermal degradation product p,p′-DDE during GC analysis was established by injecting a series of p,p′-Cl-DDT standards into the GC. The concentrations of measured p,p′-DDE and injected p,p′-ClDDT can be best fitted (R2 ) 0.9993) with eq 1:

[p,p′-DDE] ) 0.46[p,p′-Cl-DDT]0.56

(1)

On the basis of HPLC-measured p,p′-Cl-DDT concentrations [p,p′-Cl-DDT]HPLC and GC/MS-measured p,p′-DDE concentrations [p,p′-DDE]GC in dicofol samples, the p,p′-DDE concentration in the dicofol samples [p,p′-DDE]d were calculated by using

[p,p′-DDE]d ) [p,p′-DDE]GC - 0.46 × [p,p′-Cl-DDT]HPLC0.56 (2) [p,p′-Cl-DDT]HPLC, [p,p′-DDE]GC, and [p,p′-DDE]d are shown in Figure 1. The calculated concentrations of p,p′DDE in the dicofol samples were in the range of -15.5 to 5.4 g per kg dicofol and were only -16 to 15% of p,p′-Cl-DDT. This suggests very little p,p′-DDE was produced during dicofol synthesis, and p,p′-DDE in the dicofol samples was negligible compared with p,p′-Cl-DDT. The negative values were likely due to the errors in determining the regression coefficients in eq 1. Figure 1 shows that the formulated dicofol samples had high p,p′-Cl-DDT contents, that is, from 32 to 166 g per kg dicofol. This suggests the concentrations of p,p′-Cl-DDT in the environment could also be high in areas where dicofol has been extensively used. p,p′-Cl-DDT has no insecticidal activity (10-13) and can be converted to p,p′-DDE in the environment (14-16). There is little information about the environmental concentrations of p,p′-Cl-DDT. Because of thermal degradation during GC analysis, p,p′-Cl-DDT in the environment could have been underestimated as this is the general method for determining DDTs in the environment. A sensitive, selective method that will not thermally decom-

FIGURE 2. Concentrations of four major DDT impurities (o,p′-DDT, o,p′-DDE, p,p′-DDT, p,p′-Cl-DDT) analyzed with HPLC and GC/MS in the formulated dicofol samples. pose p,p′-Cl-DDT is required to obtain more accurate measurement of the concentrations of this compound in different media, such as air, water, and soil. p,p′-DDE in the environment is believed most of time to solely come from the degradation of p,p′-DDT. Therefore, the concentration ratio of p,p′-DDE/p,p′-DDT was usually used as an indicator for resident time of p,p′-DDT in the environment (17, 18). However, in areas with intensive use of dicofol containing high DDT concentrations, p,p′-DDE in the air or other media is originated not only from the degradation of p,p′-DDT but also from the degradation of p,p′-Cl-DDT in the environment and during GC analysis, which causes an overestimation of the p,p′-DDE concentrations. Therefore, the p,p′-DDE/p,p′-DDT ratio is not a valid method to evaluate the “old” or “new” source of p,p′-DDT in these regions. Because of its molecular structure, o,p′-Cl-DDT might be more unstable than p,p′-Cl-DDT during GC analysis. However, we were unable to quantify the concentration of o,p′Cl-DDT and o,p′-DDE in the dicofol samples, because no o,p′-Cl-DDT standard was obtained in our study to quantify o,p′-DDE from the thermal degradation of o,p′-Cl-DDT during GC analysis. In the presented work, a 100% conversion of o,p′-Cl-DDT to o,p′-DDE was assumed, and the GC/MSmeasured o,p′-DDE concentrations were taken as the sum of o,p′-Cl-DDT and o,p′-DDE in the dicofol samples. DDT Impurities in Dicofol. Besides the four major DDT impurities (o,p′-DDT, o,p′-DDE, p,p′-DDT, and p,p′-Cl-DDT), analyzed with HPLC or GC/MS, GC/MS analysis in full scan mode showed several impurities in the dicofol samples with mass spectrum similar to DDT or DDE. They were likely the o,o′- or m,p′- isomers of DDT or DDE. However, no attempt was made to quantify them because of the lack of standards and low concentrations of these impurities. The concentrations of o,p′-DDT, o,p′-DDE, p,p′-DDT, and p,p′-Cl-DDT in the formulated dicofol samples from the seven manufacturers are shown in Figure 2 and in the Supporting Information. In the 23 samples, the average concentrations and standard deviations (g per kg dicofol) of o,p′-DDT, p,p′Cl-DDT, o,p′-DDE, and p,p′-DDT were 114 ( 45, 69 ( 40, 44 ( 25, and 17 ( 8, respectively, and were 46, 29, 18, and 7% of the total concentrations of the four DDTs, respectively. Sample E4 had the highest concentration of the four DDTs (351 g per kg dicofol). Manufacturers A-E produced more than 85% of technical dicofol in China in 2002. It is therefore reasonable to conclude that dicofol produced and used in China have very high DDT concentrations.

In the late 1970s, China began to produce and use dicofol. After the ban of technical DDT in agriculture in 1983, China has continued producing DDT for export and for dicofol production. Figure 3 shows the output of technical DDT and technical dicofol between 1988 and 2002 in China and the estimated amount of technical DDT used to produce dicofol (data source: Sino-Italy joint project, UNDP Project CPR/ 01/R51/A/CC/31). Between 1988 and 2002, 97 000 t of technical DDT was produced in China, of which 54 000 t was used to manufacture about 40 000 t dicofol, which was mainly used within China. Using DDTs to represent o,p′-DDT, o,p′-DDE, p,p′-DDT, and p,p′-Cl-DDT in technical dicofol, and assuming DDT contents in the technical dicofol produced in the 15 years were the same, then the use of 40 000 t of technical dicofol for mite control has discharged 8770 t of DDTs into the environment, including 4420 t o,p′-DDT, 2240 t p,p′-Cl-DDT, 1450 t o,p′DDE, and 660 t p,p′-DDT. In 2002, the discharge of o,p′DDT, p,p′-Cl-DDT, o,p′-DDE, and p,p′-DDT were 372, 179, 115, and 56 t, respectively. o,p′-DDT/p,p′-DDT and Dicofol Type DDT Pollution. Figure 2 shows that concentrations of o,p′-DDT in the formulated dicofol samples were much higher than that of p,p′-DDT. Except samples F and G in which p,p′-DDT was not detected, the concentration ratio of o,p′-DDT/p,p′-DDT in the 21 samples ranged from 1.3 to 9.3, with a mean of 7.0. This ratio was much higher than that in technical DDT, in which o,p′-DDT content ranged from 15 to 21% and p,p′DDT from 65 to 85% (19). With mass balance analysis based on dicofol synthesis reaction and ignoring other minor byproducts, the concentrations of p,p′-DDT and o,p′-DDT in technical DDT (noted with TD) and the concentrations p,p′-dicofol, o,p′-dicofol, and DDT impurities in technical dicofol (noted with d) have the following relationship: [o,p′-DDT]TD

) [p,p′-DDT]TD [o,p′-dicofol]d + [o,p′-DDT]d + [o,p′-Cl-DDT]d + [o,p′-DDE]d [p,p′-dicofol]d + [p,p′-DDT]d + [p,p′-Cl-DDT]d + [p,p-DDE]d

(3) Assuming [o,p′-DDT]TD/[p,p′-DDT]TD ) 0.25 and GC/MSmeasured o,p′-DDE concentrations are equal to the sum of o,p′-Cl-DDT and o,p′-DDE in the dicofol samples, one can estimate on the basis of the results shown in Figure 2 that VOL. 39, NO. 12, 2005 / ENVIRONMENTAL SCIENCE & TECHNOLOGY

9

4387

FIGURE 3. Production of technical DDT and dicofol in China between 1988 and 2002 (data source: Sino-Italy Joint Project, UNDP Project CPR/01/R51/A/CC/31). during the synthesis reactions, on average 93% p,p′-DDT was converted to p,p′-dicofol, while only 37% o,p′-DDT was converted to o,p′-dicofol. The o,p′-dicofol/p,p′-dicofol ratios in the samples were about 0.1, much lower than 0.2-0.3 for o,p′-DDT/p,p′-DDT in technical DDT (20). The reason that conversion of o,p′-DDT to o,p′-dicofol is much lower than p,p′-DDT to p,p′-dicofol might be due to the effect on dicofol synthesis reaction caused by a structural difference between the p,p′- and o,p′-isomers of DDT. The hindrance of the ortho-chlorine atom on the benzene ring makes it more difficult for o,p′-DDT to be chlorinated to o,p′-Cl-DDT than for p,p′-DDT to p,p′-Cl-DDT. To evaluate this effect, potential energies of the p,p′- and o,p′- isomers of DDT and Cl-DDT were calculated using G98 program (21) at the HF/6-31G* level. The results show that the chlorination of p,p′-DDT and o,p′-DDT releases 13.46 and 13.26 kcal/ mol, respectively. The essentially same energy values for the two processes indicate that the higher chlorination rate of p,p′-DDT than that of o,p′-DDT may be due to kinetic instead of thermodynamic reasons. Technical DDT has been banned in agriculture for decades. In regions where dicofol with high DDT concentration is currently used, one can expect a high concentration ratio of o,p′-DDT/p,p′-DDT in the environment. o,p′-DDT metabolizes more readily than p,p′-DDT in the environment (22, 23), and the degradation of technical DDT is unlikely to cause o,p′-DDT/p,p′-DDT ratio in the environment higher than that of technical DDT. To distinguish the DDT pollution caused by technical dicofol from that by technical DDT, we would like to define a “dicofol type DDT pollution” as the DDT pollution caused by dicofol use and characterized with higher o,p′-DDT/p,p′-DDT concentration ratio than that of technical DDT. We have suggested that high concentrations of DDTs, especially o,p′-DDT observed in the air over the Taihu Lake in the summer of 2002, was caused by the use of dicofol (3). The field-observed o,p′-DDT/p,p′-DDT ratio was 6.3 ( 3.7 (3), and it was very close to the 7.0 ( 2.2 of the formulated dicofol samples found in this study. This suggested that fieldobserved DDT pollution was typical dicofol type DDT pollution and it is consistent with the fact that high temperature and drought in the summer of 2002 caused severe mite damage and large amounts of dicofol were used in China, especially in the cotton fields in the northern part of Jiangsu province. Higher o,p′-DDT concentrations than that of p,p′-DDT have also been observed in the air over the East China Sea 4388

9

ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 39, NO. 12, 2005

TABLE 1. Estimation of p,p′-Dicofol Used on Cotton and Fruit Trees in 2002 in China cotton

apple

pear

citrus

litchi longan total

usage (t) 1100 260 180 590 360 260 2750 proportion (%) 40.0 9.5 6.5 21.5 13.1 9.5 100

(17) and in Hong Kong (24), suggesting the contribution of dicofol type DDT pollution. In sediment samples from Santa Monica Basin, CA, o,p′-DDT/p,p′-DDT ratio in some samples ranged from 0.43 to 0.87, which was higher than that of technical DDT (20). California was one of the states that used the most dicofol in the United States (7, 25); it is more likely that the high concentrations of o,p′-DDT was actually from the use of dicofol containing high DDT impurities rather than from the acid wastes of the DDT factory (20). Spatial Distribution of Dicofol Type DDT Pollution. Dicofol is one of the major acaricides used in China. According to the field survey, technical dicofol was mainly used on cotton, citrus, litchi, longan, apple, and pear. Combining the survey results and the Agriculture Production Statistics Yearbook in 2002 (26), the proportion of dicofol used on different crops was estimated and listed in Table 1. With the data of dicofol usage and the DDT contents in the formulated dicofol samples, the spatial distribution of DDTs resulting from dicofol use in China was estimated and the results for o,p′-DDT in 2002 are shown in Figure 4. Before the ban of DDT use in agriculture, for example, in 1980, more than 60% of the technical DDT had been used on cotton fields, mainly in central and eastern China, especially in Sichuan, Hebei, Jiangsu, and Shangdong provinces; each of them used more than 1000 t of technical DDT. In comparison to central and eastern China, less technical DDT was used in southern China, such as Guangdong, Guangxi, and Fujian provinces, and no technical DDT had ever been used in Guangxi province (1). Unlike technical DDT, dicofol use in China is mainly in the southern and eastern provinces, on the basis of dicofol usage, these provinces rank as Guangdong, Guangxi, Jiangsu, and Fujian. In 2002, three southern provinces (Guangdong, Guangxi, and Fujian) in total used more than 35% of dicofol in China, mostly on litchi, longan, and citrus crops, with application rates higher than that on cotton fields, because higher temperatures in the south promoted rapid mite reproduction. Considering the difference between the spatial

FIGURE 4. Distribution of o,p′-DDT input to the environment from dicofol use in China (left) and in Jiangsu province (right) in 2002. distribution of technical DDT and dicofol use, DDT pollution in the south is very likely dominated by dicofol type DDT pollution. Recent reports on DDT concentrations in pine needles (27), sediments of the river/estuary system (28), and mussels in coastal waters (29) all suggested that the DDT pollution in southern China was far more serious than in northern China. The highest DDT concentrations were mostly found in samples from Guangdong and Fujian provinces. This suggests that while the residue of technical DDT has been decreasing in the environment since the ban of this pesticide in agriculture, the use of dicofol has become an important source of DDT pollution in the environment. However, until now, studies on DDT pollution in China have paid little attention to o,p′-DDT, which deserves more studies in future. Figure 4 shows that in the east of China, Jiangsu province has the most intensive dicofol use because of large areas under cotton cultivation. The south of Jiangsu province is part of the Yangtze River Delta, which historically has been the region with the most intensive use of technical DDT in China (1). In recent years, with fast industrialization and economic development in this region, cotton cultivation in Jiangsu province has been reduced significantly and is now mainly located in the north of the province. Consequently, the dicofol type DDT pollution in the province is concentrated in the north, especially in Dafeng and Sheyang, as is shown in Figure 4. In 2002 more than 2400 g km-2 o,p′-DDT was brought into the environment by the use of dicofol in Dafeng and 1800 g km-2 in Sheyang. Compared with the north of Jiangsu province, DDTs from dicofol use was much less in the Yangtze River Delta, especially the Taihu Lake Basin, which is located on the south side of the Yangtze River. The DDTs observed in the Taihu Lake Basin were mainly from the residue of technical DDT and from atmospheric transport, for example, air masses can bring high concentrations of DDTs especially o,p′-DDT from regions where dicofol is in use (3). From the analysis above, one can conclude that the dicofol type DDT pollution is serious in China, especially in southern and eastern China. This pollution is different from that of technical DDT in DDT contents. For dicofol type DDT pollution, p,p′-Cl-DDT is also an important component. Little is known about the concentration, behavior, and environmental impact of p,p′-Cl-DDT because of the limitations of the analysis method. The conversion of p,p′-Cl-DDT to p,p′DDE during GC analysis might lead to high p,p′-DDE/p,p′DDT ratio and could be misleading in judging the resident

time of p,p′-DDT in the environment. Therefore, more studies are needed to understand the fate of p,p′-Cl-DDT in the environment because of the use of dicofol.

Acknowledgments This study was supported by the National Outstanding Young Scholar Fund (49925513), Chinese Ministry of Science and Technology (2002CB410802), and the Sino-Italy joint project “Strategy and Planning for eliminating and phasing out Pesticide Persistent Organic Pollutants (POPs) in China” (UNDP Project CPR/01/R51/A/CC/31). The authors wish to thank Dr. Sam Kaharabata, Dr. Ray Desjardins, and three reviewers for comments that improved the manuscript.

Supporting Information Available Table of contents of dicofol, o,p′-DDT, p,p′-DDT, o,p′-DDE, and p,p′-Cl-DDT in the formulated dicofol samples from seven manufacturers collected from seven provinces. This material is available free of charge via the Internet at http:// pubs.acs.org.

Literature Cited (1) Li, Y. F.; Cai, D. J.; Singh, A. Historical DDT use trends in China and usage data gridding with 1/4 by 1/6 longitude/latitude resolution. Adv. Environ. Res. 1999, 2, 497-506. (2) Zhang, G.; Parker, A.; House, A.; Mai, B. X.; Li, X. D.; Kang, Y. H.; Wang, Z. S. Sedimentary records of DDT and HCH in the Pearl River Delta, South China. Environ. Sci. Technol. 2002, 36, 3671-3677. (3) Qiu, X. H.; Zhu, T.; Li, J.; Pan, H. S.; Li, Q. L.; Miao, G. F.; Gong, J. C. Organochlorine pesticides in the air around Taihu Lake, China. Environ. Sci. Technol. 2004, 38, 1368-1374. (4) Di Muccio, A.; Camoni, I.; Citti, P.; Pontecorvo, D. Survey of DDT-like compounds in dicofol formulations. Ecotoxicol. Environ. Saf. 1988, 16, 129-132. (5) Gillespie, M. J.; Lythgo, C. M.; Plumb, A. D.; Wilkins, J. P. G. A survey comparing the chemical composition of dicofol formulations sold in the UK before and after the introduction of the EC ‘Prohibition Directive 79/117/EEC’. Pestic. Sci. 1994, 42, 305314. (6) Tang, C. C.; Li, Y. C.; Chen, B.; Yang, H. Z.; Jin, G. Y. In Pesticide Chemistry (in Chinese); Nankai University Publishing House: Tianjian, 1998; p 230. (7) Rasenberg, M. H. C.; van de Plassche, E. J. Dicofol Dossier prepared for the meeting March 17-19 in Norway of the UNECE Ad-hoc Expert Group on POPs, 4L0002.A1/R0011/EVDP/ Nijm, January, 2003. (8) Grummitt O.; Buck A.; Jenkins A. New compounds: 1,1-Di(p-chlorophenyl)- 1,2,2,2-tetrachloroethane. J. Am. Chem. Soc. 1945, 67, 155-156. VOL. 39, NO. 12, 2005 / ENVIRONMENTAL SCIENCE & TECHNOLOGY

9

4389

(9) Risebrough, R. W.; Jarman, W. M.; Springer, A. M.; Walker, W., II; Hunt, W. G. A metabolic derivation of DDE from Kelthane. Environ. Toxicol. Chem. 1986, 5, 13-19. (10) Lord K. A. The contact toxicity of a number of D.D.T. analogues and of four isomers of benzene hexachloride to Macrosiphoniella sanborni and Oryzaephilus surinamensis. Ann. Appl. Biol. 1948, 35, 505-526. (11) Metcalf R. L. Acaracidal properties of organic compounds related to DDT. J. Econ. Entomol. 1948, 41, 875-882. (12) Rogers E. F.; Brown H. D.; Rasmussen I. M.; Heal R. E. The structure and toxicity of DDT insecticides. J. Am. Chem. Soc. 1953, 75, 2991-2999. (13) Tahori, A. S. Diaryl-trifluoromethyl-carbinols as synergists for DDT against DDT-resistant house flies. J. Econ. Entomol. 1955, 48, 638-642. (14) Beland, F. A.; Farwell, S. O.; Geer, R. D. Anaerobic degradation of 1,1,1,2-tetrachloro-2,2-bis(p-chlorophenyl)ethane(DTE). J. Agric. Food Chem. 1974, 22, 1148-1149. (15) Cole, R. B.; Metcalf, R. L. Model ecosystem determination of the metabolic and environmental fate of tetrachloro-DDT. Bull. Environ. Contam. Toxicol. 1987, 38, 96-103. (16) Brown, M. A.; Ruzo, L. O.; Casida, J. E. Photochemical conversion of a dicofol impurity, R-Chloro-DDT, to DDE, Bull. Environ. Contam. Toxicol. 1986, 37, 791-796. (17) Iwata, H.; Tanabe, S.; Sakal, N.; Tatsukawa, R. Distribution of persistent organochlorines in the oceanic air and surface seawater and the role of ocean on their global transport and fate. Environ. Sci. Technol. 1993, 27, 1080-1098. (18) McConnell, L. L.; Kucklick, J. R.; Bidleman, T. F.; Ivanov, G. P.; Chernyak, S. M. Air-water gas exchange of organochlorine compounds in Lake Baikal, Russia. Environ. Sci. Technol. 1996, 30, 2975-2983. (19) Metcalf, R. L. Organic insecticides, Their Chemistry and Mode of Action; Interscience: New York. 1955. (20) Venkatesan, M. I.; Greene, G. E.; Ruth, E.; Chartrand, A. B. DDTs and dumpsite in the Santa Monica Basin, California. Sci. Total Environ. 1996, 179, 61-71. (21) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Zakrzewski, V. G.; Montgomery, J. A., Jr.; Stratmann, R. E.; Burant, J. C.; Dapprich, S.; Millam, J. M.; Daniels, A. D.; Kudin, K. N.; Strain, M. C.; Farkas, O.; Tomasi, J.; Barone, V.; Cossi, M.; Cammi, R.; Mennucci, B.; Pomelli, C.; Adamo, C.; Clifford, S.; Ochterski, J.; Petersson, G. A.; Ayala, P. Y.; Cui, Q.; Morokuma, K.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.; Cioslowski, J.; Ortiz, J. V.;

4390

9

ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 39, NO. 12, 2005

(22) (23)

(24)

(25) (26)

(27)

(28)

(29)

Stefanov, B. B.; Liu, G.; Liashenko, A.; Piskorz, P.; Komaromi, I.; Gomperts, R.; Martin, R. L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.; Gonzalez, C.; Challacombe, M.; Gill, P. M. W.; Johnson, B. G.; Chen, W.; Wong, M. W.; Andres, J. L.; Head-Gordon, M.; Replogle, E. S.; Pople, J. A. Gaussian 98, revision A.7; Gaussian, Inc.: Pittsburgh, PA, 1998. MacGregor, J. S. DDT and its metabolites in the sediments of southern California. Fish. Bull. 1976, 74, 27-35. Martijn, A.; Bakker, H.; Schreuder, R. H. Soil persistence of DDT, dieldrin, and lindane over a long period. Bull. Environ. Contam. Toxicol. 1993, 51, 178-184. Louie, P. K. K.; Sin, D. W. M. A preliminary investigation of persistent organic pollutants in ambient air in Hong Kong. Chemosphere 2003, 52, 1397-1403. Domagalski, J. Occurrence of dicofol in the San Joaquin River, California. Bull. Environ. Contam. Toxicol. 1996, 57, 284-291. Provincial Agriculture Production Statistics Yearbook in 2002 of Anhui, Fujian, Guangdong, Guangxi, Hainan, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Liaoning, Shandong, Shanxi, and Zhejiang provinces; City and County Agriculture Production Statistics Yearbook in Jiangsu province, including Changzhou, Lianyungang, Nanjing, Nantong, Suzhou, Wuxi, Xuzhou, and Yancheng. Compiled by Statistics Bureau of each province or city, China Statistics Press: Beijing, 2003. Xu, D. D.; Zhong, W. K.; Deng, L. L.; Chai, Z. F.; Mao, X. Y. Regional distribution of organochlorinated pesticides in pine needles and its indication for socioeconomic development. Chemosphere 2004, 54, 743-752. Wu, Y.; Zhang, J.; Zhou, Q. Persistent organochlorine residues in sediments from Chinese river/estuary systems. Environ. Pollut. 1999, 105, 143-150. Monirith, I.; Ueno, D.; Takahashi, S.; Nakata, H.; Sudaryanto, A.; Subramanian, A.; Karuppiah, S.; Ismail, A.; Muchtar, M.; Zheng, J.; Richardson, B. J.; Prudente, M.; Hue, N. D.; Tana, T. S.; Tkalin, A. V.; Tanabe, S. Asia-Pacific mussel watch: monitoring contamination of persistent organochlorine compounds in coastal waters of Asian countries. Mar. Pollut. Bull. 2003, 46, 281-300.

Received for review February 19, 2005. Revised manuscript received March 23, 2005. Accepted March 24, 2005. ES050342A