Human health and environment: Spatiotemporal variation of chinese cancer villages and its contributing factors

Abstract

Cancer, as well as the phenomena of cancer villagers, has attracted great concern from national and internal publics because of the high morality for population. Reference to long latency periods and multiple causalities for several cancers, cancer villages have usually used as circumstantial evidence for an association with cancers and environmental determinants relevant to economic-agricultural and demographic development even though there was no official definition and unified discrimination rule. On the assumption that all reported cancer villages are real and credible, this study primarily aimed to test the hypothesis that the water quality has caused concentration of cancer villages. The temporal and spatial pattern of Chinese cancer villages reported by media and literatures were firstly explored by means of spatial mapping and regression analysis. Considering the insignificant Moran'I coefficient, stepwise regression model combined with principal component regression model were performed to identify the association between cumulative number of cancer villages and water quality and other social-economic-environmental factors. The findings showed that there are at least 462 cancer villages across 226 counties in 29 out of 31 provincial administrative units were reported in China by the end of 2017, with an average of 7 new cancer villages per year, since the initial cancer village appeared in 1954. The number of cancer villages increased slowly before 2000 and dramatically accelerated during 10th and 11th Five-Year Plan period. The cumulative number of cancer villages increased gradient from West to East with regionally clustered and uneven spatial distribution. Cancer villages tend to cluster along the middle and lower reaches of major rivers and their branches, especially in Yangtze River Delta, the Bohai economic rim, the borders of Hunan, Hubei and Jiangxi provinces, as well as the borders of Yunnan and Guizhou province. Cumulative occurrence of cancer villages might be affected by domestic economic development, urbanization, as well as discharge of heavy metals in waste industrial water.