Environ Sci Pollut Res (2015) 22:1309–1317 DOI 10.1007/s11356-014-3469-4
RESEARCH ARTICLE
Cancer risks and long-term community-level exposure to pentachlorophenol in contaminated areas, China Pan Cheng & Qinghe Zhang & Xiaomei Shan & Denghui Shen & Bingshuang Wang & Zhenhai Tang & Yu Jin & Chi Zhang & Fen Huang
Received: 20 June 2014 / Accepted: 14 August 2014 / Published online: 21 August 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract Widespread use of pentachlorophenol (PCP) in schistosomiasis endemic areas had led to ubiquitous exposure to PCP and its residues. Numerous studies had revealed that occupational PCP exposure probably increased risk of cancers, but whether long-term community-level exposure to PCP generates the similarly carcinogenic effect, seldom studies focused on it. This study was to explore the cancer risks of long-term community-level PCP exposure from drinking water in a Chinese general population. Incident (2009–2012) cancer records were identified by local government national registry. And PCP concentration of raw drinking water samples in each district was measured by GC-MS/MS analysis for further division of three PCP exposure categories by interquartile range (high vs. medium vs. low). Internal comparisons were performed, and standard rate ratio was calculated to describe the relationship between PCP exposure and cancer risks by using low-exposure group as the reference group.
PCP was detected in all 27 raw drinking water samples ranging from 11.21 to 684.00 ng/L. A total of 6,750 cases (4,409 male and 2,341 female cases) were identified, and agestandardized rate (world) was 154.95 per 100,000 personyears. The cancer incidence for the high-exposure group was remarkably high. Internal comparisons indicated that high PCP exposure might be positively associated with high cancer risks in the community population, particularly for leukemia (SRR = 5.93, 95 % CI = 5.24–6.71), maligant lymphoma (SRR=2.27, 95 % CI=2.10–2.54), and esophageal cancer (SRR=2.42, 95 % CI=2.35–2.50). Long-term communitylevel exposure to PCP was probably associated with hemolymph neoplasm, neurologic tumors, and digestive system neoplasm. Keywords Pentachlorophenol . Cancer risk . General population . Community-level . Ecological design . Drinking water
Responsible editor: Philippe Garrigues Pan Cheng and Qinghe Zhang contributed equally to this work. P. Cheng : Q. Zhang : Z. Tang : Y. Jin : C. Zhang : F. Huang (*) Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, No. 81 Meishan Road, Shushan District, Hefei, Anhui 230032, China e-mail: [email protected] Q. Zhang Wuhu Hospital of Traditional Chinese Medicine, Wuhu, Anhui 241003, China X. Shan Physical and Chemical Laboratory of Anhui Provincial Center for Disease Control and Prevention, Hefei, Anhui 230601, China X. Shan : D. Shen : B. Wang Department of Occupational and Environmental Health, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China
Introduction Pentachlorophenol (PCP) (2,3,4,5,6-pentachlorophenol) and its sodium salt (Na-PCP) is a chlorinated aromatic compound that has been used extensively as wood preservative, herbicide, and insecticide in western countries since 1930s (Hurd et al. 2012). International Agency for Research on Cancer (IARC) and the U.S. Environmental Protection Agency (EPA) classified PCP as a group 2B carcinogen (possible human carcinogen) based on sufficient evidence in animal studies but inadequate evidence in humans by evaluation of available literature conducted in the 1990s (U.S. EPA 1991; IARC 1999). PCP was restricted or banned to use in many countries in 1984 and included in the list of priority pollutants (U.S. EPA 2001). However, because of its low cost and broad spectrum, PCP and fungicidal sodium salts were primarily
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used to kill schistosome intermediate host snails which were epidemic mainly in China's southern provinces across the Yangtze River watershed and areas on the south of the Yangtze River since 1960s (Li and Cai 2004). About 60 % of the national production was applied for this purpose in China (CESE 2004), while the rest was used in wood preservation and other uses. Moreover, PCP was totally replaced by niclosamide as molluscacide till 2002 in all schistosomiasis endemic areas (Zheng et al. 2013b). As the forbidden use of PCP was later than other counties, its derivatives had resulted in serious pollution in the schistosomiasis epidemic area. Zheng et al. (2011) reported that the PCP levels had declined over time in western countries with half-lives ranging from 2.0 to 11.1 years, and global human burden of PCP had been decreasing to low levels along with declining trends in PCP levels in the environmental media in this decade, because of restrictions and bans on PCP production and use. However, PCP and its Na-PCP had been widely sprayed in the middle and lower reaches of the Yangtze River to control the spread of schistosomiasis (Nie et al. 2013) from 1960 to 2002 in China. As slow elimination in surface waters, high persistence in sediments, and formation of stable metabolites (Ahlborg and Thunberg 1980), PCP levels were significantly higher in schistosomiasis epidemic areas than in control areas. PCP contamination existed in Chinese surface water widely and PCP contamination in the Yangtze River was the severest among the seven watersheds and three drainage areas, with a median value of 50.0 ng/L (range 66 %; (ii) death certificate only (DCO%) of 0.6 and 13.10 ng/L and 3.0), while the numbers of cancer cases were small. And high SRRs of high exposure to PCP existed in the cancer sites of stomach, bladder, lung, and liver.
Discussion With the re-emergence of schistosomiasis in the traditional epidemic areas of China, the production and use of PCP for snail elimination and schistosomiasis control might increase once again (Zhou et al. 2005; Zheng et al. 2012). Recently, there is a growing concern about PCP and cancer risks, while
Environ Sci Pollut Res (2015) 22:1309–1317
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Table 1 Cancer incidence of three PCP exposure groups by sex in Tongling from 2009 to 2012 Exposure group Total population Male
Female
N value Rude rate ASR China
ASR World
Total
N value Rude rate ASR China
ASR World
N value Rude rate ASR China
Low
84983
477
274.78
137.97 199.31 248
149.09
78.95
Medium High Total
599962 39018 723963
3552 380 4409
289.84 476.78 298.14
143.19 213.55 1926 239.67 337.34 167 147.78 207.01 2341
164.01 218.67 165.20
86.22 112.26 5478 123.53 160.79 547 93.03 104.46 6750
102.44 725
ASR World
213.28
114.56 150.89
228.26 350.48 233.10
120.69 161.93 191.24 249.60 123.77 154.95
N; the cases of cancer patients ASR China; age-standard rate by Chinese 1982 model population, per 100,000 person-years ASR World; age-standard rate by Segi’s world standard population, per 100,000 person-years
previous similar studies were all about occupational workers exposing to PCP which might be limited by healthy worker effect to draw conclusions. Based on our previous research, which indicated that high PCP exposure was positively associated with risk of caners in the community population (Zheng et al. 2013b), this study further explored new evidence of general population data on the associations between cancer risks and long-term community-level PCP exposure in a general population by examining the concentration of PCP in raw Fig. 2 Annual average incidence rate of all cancers, stomach cancer, liver cancer, and malignant lymphoma by PCP exposure and age groups. * Indicating the difference of the annual average incidence rate between high and low-PCP exposure groups was statistically significant (P
RESEARCH ARTICLE
Cancer risks and long-term community-level exposure to pentachlorophenol in contaminated areas, China Pan Cheng & Qinghe Zhang & Xiaomei Shan & Denghui Shen & Bingshuang Wang & Zhenhai Tang & Yu Jin & Chi Zhang & Fen Huang
Received: 20 June 2014 / Accepted: 14 August 2014 / Published online: 21 August 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract Widespread use of pentachlorophenol (PCP) in schistosomiasis endemic areas had led to ubiquitous exposure to PCP and its residues. Numerous studies had revealed that occupational PCP exposure probably increased risk of cancers, but whether long-term community-level exposure to PCP generates the similarly carcinogenic effect, seldom studies focused on it. This study was to explore the cancer risks of long-term community-level PCP exposure from drinking water in a Chinese general population. Incident (2009–2012) cancer records were identified by local government national registry. And PCP concentration of raw drinking water samples in each district was measured by GC-MS/MS analysis for further division of three PCP exposure categories by interquartile range (high vs. medium vs. low). Internal comparisons were performed, and standard rate ratio was calculated to describe the relationship between PCP exposure and cancer risks by using low-exposure group as the reference group.
PCP was detected in all 27 raw drinking water samples ranging from 11.21 to 684.00 ng/L. A total of 6,750 cases (4,409 male and 2,341 female cases) were identified, and agestandardized rate (world) was 154.95 per 100,000 personyears. The cancer incidence for the high-exposure group was remarkably high. Internal comparisons indicated that high PCP exposure might be positively associated with high cancer risks in the community population, particularly for leukemia (SRR = 5.93, 95 % CI = 5.24–6.71), maligant lymphoma (SRR=2.27, 95 % CI=2.10–2.54), and esophageal cancer (SRR=2.42, 95 % CI=2.35–2.50). Long-term communitylevel exposure to PCP was probably associated with hemolymph neoplasm, neurologic tumors, and digestive system neoplasm. Keywords Pentachlorophenol . Cancer risk . General population . Community-level . Ecological design . Drinking water
Responsible editor: Philippe Garrigues Pan Cheng and Qinghe Zhang contributed equally to this work. P. Cheng : Q. Zhang : Z. Tang : Y. Jin : C. Zhang : F. Huang (*) Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, No. 81 Meishan Road, Shushan District, Hefei, Anhui 230032, China e-mail: [email protected] Q. Zhang Wuhu Hospital of Traditional Chinese Medicine, Wuhu, Anhui 241003, China X. Shan Physical and Chemical Laboratory of Anhui Provincial Center for Disease Control and Prevention, Hefei, Anhui 230601, China X. Shan : D. Shen : B. Wang Department of Occupational and Environmental Health, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China
Introduction Pentachlorophenol (PCP) (2,3,4,5,6-pentachlorophenol) and its sodium salt (Na-PCP) is a chlorinated aromatic compound that has been used extensively as wood preservative, herbicide, and insecticide in western countries since 1930s (Hurd et al. 2012). International Agency for Research on Cancer (IARC) and the U.S. Environmental Protection Agency (EPA) classified PCP as a group 2B carcinogen (possible human carcinogen) based on sufficient evidence in animal studies but inadequate evidence in humans by evaluation of available literature conducted in the 1990s (U.S. EPA 1991; IARC 1999). PCP was restricted or banned to use in many countries in 1984 and included in the list of priority pollutants (U.S. EPA 2001). However, because of its low cost and broad spectrum, PCP and fungicidal sodium salts were primarily
1310
used to kill schistosome intermediate host snails which were epidemic mainly in China's southern provinces across the Yangtze River watershed and areas on the south of the Yangtze River since 1960s (Li and Cai 2004). About 60 % of the national production was applied for this purpose in China (CESE 2004), while the rest was used in wood preservation and other uses. Moreover, PCP was totally replaced by niclosamide as molluscacide till 2002 in all schistosomiasis endemic areas (Zheng et al. 2013b). As the forbidden use of PCP was later than other counties, its derivatives had resulted in serious pollution in the schistosomiasis epidemic area. Zheng et al. (2011) reported that the PCP levels had declined over time in western countries with half-lives ranging from 2.0 to 11.1 years, and global human burden of PCP had been decreasing to low levels along with declining trends in PCP levels in the environmental media in this decade, because of restrictions and bans on PCP production and use. However, PCP and its Na-PCP had been widely sprayed in the middle and lower reaches of the Yangtze River to control the spread of schistosomiasis (Nie et al. 2013) from 1960 to 2002 in China. As slow elimination in surface waters, high persistence in sediments, and formation of stable metabolites (Ahlborg and Thunberg 1980), PCP levels were significantly higher in schistosomiasis epidemic areas than in control areas. PCP contamination existed in Chinese surface water widely and PCP contamination in the Yangtze River was the severest among the seven watersheds and three drainage areas, with a median value of 50.0 ng/L (range 66 %; (ii) death certificate only (DCO%) of 0.6 and 13.10 ng/L and 3.0), while the numbers of cancer cases were small. And high SRRs of high exposure to PCP existed in the cancer sites of stomach, bladder, lung, and liver.
Discussion With the re-emergence of schistosomiasis in the traditional epidemic areas of China, the production and use of PCP for snail elimination and schistosomiasis control might increase once again (Zhou et al. 2005; Zheng et al. 2012). Recently, there is a growing concern about PCP and cancer risks, while
Environ Sci Pollut Res (2015) 22:1309–1317
1313
Table 1 Cancer incidence of three PCP exposure groups by sex in Tongling from 2009 to 2012 Exposure group Total population Male
Female
N value Rude rate ASR China
ASR World
Total
N value Rude rate ASR China
ASR World
N value Rude rate ASR China
Low
84983
477
274.78
137.97 199.31 248
149.09
78.95
Medium High Total
599962 39018 723963
3552 380 4409
289.84 476.78 298.14
143.19 213.55 1926 239.67 337.34 167 147.78 207.01 2341
164.01 218.67 165.20
86.22 112.26 5478 123.53 160.79 547 93.03 104.46 6750
102.44 725
ASR World
213.28
114.56 150.89
228.26 350.48 233.10
120.69 161.93 191.24 249.60 123.77 154.95
N; the cases of cancer patients ASR China; age-standard rate by Chinese 1982 model population, per 100,000 person-years ASR World; age-standard rate by Segi’s world standard population, per 100,000 person-years
previous similar studies were all about occupational workers exposing to PCP which might be limited by healthy worker effect to draw conclusions. Based on our previous research, which indicated that high PCP exposure was positively associated with risk of caners in the community population (Zheng et al. 2013b), this study further explored new evidence of general population data on the associations between cancer risks and long-term community-level PCP exposure in a general population by examining the concentration of PCP in raw Fig. 2 Annual average incidence rate of all cancers, stomach cancer, liver cancer, and malignant lymphoma by PCP exposure and age groups. * Indicating the difference of the annual average incidence rate between high and low-PCP exposure groups was statistically significant (P
