The Lag Effect of Water Pollution on the Mortality Rate for Esophageal Cancer in a Rapidly Industrialized Region in China
Total Page:16
File Type:pdf, Size:1020Kb
Environmental Science and Pollution Research https://doi.org/10.1007/s11356-019-06408-z RESEARCH ARTICLE The lag effect of water pollution on the mortality rate for esophageal cancer in a rapidly industrialized region in China Chengdong Xu1 & Dingfan Xing2 & Jinfeng Wang1 & Gexin Xiao3 Received: 22 March 2019 /Accepted: 3 September 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract The Huai River basin (located in eastern China) has a population of 180 million and has the highest risk of esophageal cancer (EC) mortality in China. Some studies found that contaminants in drinking water are a major risk factor for cancers of the digestive system. However, the effect of water pollution in the historical period on the current EC mortality remains unclear. Data were collected on the EC mortality rate in 2004 in the Huai River basin in 11 counties, and data on the surface water quality in the region from 1987 to 2004 were used. The Pearson correlation and the GeoDetector q-statistic were employed to explore the association between water pollution and the EC mortality rate in different lag periods, from linear and nonlinear perspectives, respectively. The study showed apparently spatial heterogeneity of the EC mortality rate in the region. The EC mortality rate downstream is significantly higher than that in other regions; in the midstream, the region north of the mainstream has a lower average mortality rate than that south of the area. Upstream, the region north of the mainstream has a higher mortality rate than that in the southern area. The spatial pattern was formed under the influence of water pollution in the historical period. 1996, 1997, and 1998 have the strongest linear or nonlinear effect on the EC mortality rate in 2004, in which the Pearson correlation coefficient and the q-statistic were the highest, 0.79 and 0.89, respectively. Rapid industrialization in the past 20 years has caused environmental problems and poses related health risks. The study indicated that the current EC mortality rate was mainly caused by water pollution from the previous 8 years. The findings provide knowledge about the lag time for pollution effects on the EC mortality rate, and can contribute to the controlling and preventing esophageal cancer. Keywords Esophageal cancer . Lag effect . Water pollution . Spatial analysis . Rapid industrialization Introduction Esophageal cancer (EC) is a type of digestive tract cancer, Responsible editor: Philippe Garrigues ranked the eighth most common cancer worldwide and the sixth deadliest cancer. The 5-year survival rate ranges from * Jinfeng Wang 15 to 25% globally (Ferlay et al. 2010). [email protected] According to GLOBOCAN statistics, it is estimated that * Gexin Xiao about 400,200 people die of this disease annually worldwide, [email protected] and the mortality rate for EC is increasing rapidly (Torre et al. Chengdong Xu 2015). Although great efforts have been made to control the [email protected] risk of EC, no prevention or early detection strategy has been Dingfan Xing proven conclusively to reduce the risk (Reid et al. 2010; [email protected] Pennathur et al. 2013). Understanding risk factors affecting EC and reducing the incidence and mortality of the disease 1 State Key Laboratory of Resources and Environmental Information System, Institute of Geographic Sciences and Natural Resources remains a challenge. Research, Chinese Academy of Sciences, Beijing, China EC is caused by various factors (Ribeiro et al. 1996). The 2 School of Information Engineering, China University of association between the EC mortality rate and environmental Geosciences, Beijing 100083, China pollution factors has been analyzed in a large number of studies. 3 China National Center For Food Safety Risk Assessment, Researchers have investigated water pollution (van Maanen Beijing 100022, China et al. 1996;Beaumontetal.2008); coal cooking pollution in Environ Sci Pollut Res indoor environments (Pan et al. 1999); concentrations of harm- is about 270,000 km2 (Fig. 1). The population density in 2 ful gases, such as PM10, PM2.5, and NO2, in outdoor air the region is 615 people/km , which is four times the (Huang et al. 2017;Weinmayretal.2018); and concentrations average population density of the entire country. Since of heavy metals, for example, selenium (Se) and zinc (Zn), in the 1980s, the Huai River basin has been suffering serious soil (Semnani et al. 2010; Keshavarzi et al. 2012). water pollution. China has one of the highest incidence rates of EC in the so-called Asian belt, accounting for 51.9% of the people who Data die from EC globally (Di et al. 2016). In China, the Huai River basin has the highest risk of EC mortality. According to the Data on the EC mortality rates in the Huai River basin were Chinese Third National Causes of Death Sampling Survey obtained from the Chinese Center for Disease Control and (2004–2005), the national mortality rate for EC is 15.21 per Prevention and were age-standardized based on the census 100,000, but the rate in the Huai River basin is five times data in 2000. The study area included 11 counties in four higher than the average national rate (Wei et al. 2010). provinces: Xiping County, Shenqiu County, and Luoshan Since the 1980s, water pollution has become a significant County in Henan Province; Lingbi County, Yongqiao problem in China, due to rapid industry and agriculture County, Yingdong County, Shou County, and Mengcheng growth (Fu et al. 2007). A national survey carried out in County in Anhui Province; Jinhu County and Xuyi County 2004 revealed that 28% of 412 sections monitored for water in Jiangsu Province; and Wenshang County in Shandong quality were over grade V, the worst grade in the national Province (Fig. 1). standard for water quality (Shao et al. 2006). The Huai River Data on the quality of the surface water in the Huai River basin, located in eastern China, is a typical region representing basin were obtained from the China Environmental Quality industrialization in a densely populated area. Since the 1980s, Report (1987–2004) released by the State Environmental the water quality in the Huai River basin has been deteriorat- Protection Administration (Fig. 2). The water quality monitor- ing every year. By the end of 1995, more than 80% of the ing indicators included biochemical oxygen demand (BOD), + rivers and other water bodies in the areas examined were con- chemical oxygen demand (COD), NH4 ,NH3, and volatile taminated (Tan et al. 2005). Chemical contaminants from un- phenol. protected and untreated industrial and domestic wastewater Overall, the water quality grade increased from 1987 to put residents’ health at risk (Zhang et al. 2010). Several pre- 1995 (higher grade represent more pollution), and by vious epidemiological studies suggested that contaminants in 1995, the water pollution level of the Huai River peaked. drinking water, for example, nitrate and nitrite, are a major risk Between 1987 and 2003, the water quality deteriorated factor for cancers of the digestive system (Murphy 1991; Yang from upstream to downstream, ranging from Grade III to et al. 2007). Numerous studies have found associations be- Grade VI (Water Quality Standards: GB3838-1988, tween water pollution and the incidence or mortality rate for GB3838-2002), which means that the water was not suit- EC (Tao et al. 2000; Cai et al. 2002; Zhang et al. 2003; Zhang able for drinking directly (Fig. 3). The severe water pol- et al. 2014). However, to our knowledge, no studies have lution in the Huai River basin has attracted the attention analyzed the lag effect of water pollution on the mortality rate of the Chinese government. In 1996, the State Council for EC, and how long the effect of water pollution on EC in the approved the Five-Year Plan for Water Pollution Huai River basin of China lasts remains unclear. Prevention and Control in the Huai River basin policy. This paper is organized as follows. The next section describes The policy stated that the Huai River had to be clean data and methods. The “Results” section presents the results from before the end of the twentieth century; thus, the pollution linear and nonlinear methods. Discussions and conclusions are in of the Huai River was alleviated during the following 5 the “Discussion” section. In this study, the lag effect of water years. This plan ended in 2000, and the pollution in the pollution on the mortality rate of EC was analyzed using mortal- Huai River rebounded during the following 3 years due to ity data for EC in 11 counties in the Huai River basin in 2004, as the short-term decline in local government supervision. well as water pollution data from 1987 to 2004. Methods Data and methods The association between long-term exposure to water pol- lution and EC mortality rates was quantified with linear Study area and nonlinear models. In a linear model, the parameters are clear, and the calculation is easy to implement and is The Huai River basin, located in eastern China (30° 55′– repeatable. However, the relationship between disease and 36° 36′ N, 111° 55′–121° 25′ E), spans four provinces environment in reality is fundamentally nonlinear. A lin- (Henan, Anhui, Jiangsu, and Shandong). The total area ear method is a first-order approximation for reality, and a Environ Sci Pollut Res Fig. 1 EC mortality rate for 11 counties in the Huai River basin and 16 monitoring stations L linear model cannot fully account for the relationship 2 ∑ N hσh compared with nonlinear methods. In this study, the h¼ SSW q ¼ 1− 1 ¼ 1− Pearson correlation coefficient and the GeoDetector q-sta- Nσ2 SST L tistic were selected to reveal the association between long- 2 SSW ¼ ∑ N hσh term exposure to water pollution and EC mortality rates, h¼1 in linear and nonlinear perspectives.