Epidemiological studies on residential radon exposure and the risk of histological types of lung cancer have yielded inconsistent results. We conducted a meta-analysis on this topic and updated previous related meta-analyses. We searched the databases of Cochrane Library, Embase, PubMed, Web of Science and Chinese National Knowledge Infrastructure for papers published up to 13 November 2018. The pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using fixed and random effects models. Subgroup and dose‒response analyses were also conducted. This study was registered with PROSPERO (No. CRD42019127761). A total of 28 studies, which included 13,748 lung cancer cases and 23,112 controls, were used for this meta-analysis. The pooled OR indicated that the highest residential radon exposure was significantly associated with an increased risk of lung cancer (OR = 1.48, 95% CI = 1.26–1.73). All histological types of lung cancer were associated with residential radon. Strongest association with small-cell lung carcinoma (OR = 2.03, 95% CI = 1.52–2.71) was found, followed by adenocarcinoma (OR = 1.58, 95% CI = 1.31–1.91), other histological types (OR = 1.54, 95% CI = 1.11–2.15) and squamous cell carcinoma (OR = 1.43, 95% CI = 1.18–1.74). With increasing residential radon levels per 100 Bq/m3, the risk of lung cancer, small-cell lung carcinoma and adenocarcinoma increased by 11%, 19% and 13%, respectively. This meta-analysis provides new evidence for a potential relationship between residential radon and all histological types of lung cancer.

For the last 20-odd years in China, an economic boom has resulted in severe environmental pollution; water pollution, particularly, is of great concern. It has been reported that pollution in China's overall surface water is rated medium. The water quality of groundwater, lakes and reservoirs has deteriorated. Consequently, such a general distribution of water pollution has posed a grave threat to public health in China. The health impact of water pollution has been documented in the last several decades; these documents are reviewed in this paper on several outstanding aspects, including chronic mercurialism, arsenism, cancers related to microcystins, health problems caused by organic pollutants and water pollution accidents as well. Indubitably, water pollution and its health impact remain enormous challenges in China.

For the last 20-odd years in China, an economic boom has resulted in severe environmental pollution; water pollution, particularly, is of great concern. It has been reported that pollution in China's overall surface water is rated medium. The water quality of groundwater, lakes and reservoirs has deteriorated. Consequently, such a general distribution of water pollution has posed a grave threat to public health in China. The health impact of water pollution has been documented in the last several decades; these documents are reviewed in this paper on several outstanding aspects, including chronic mercurialism, arsenism, cancers related to microcystins, health problems caused by organic pollutants and water pollution accidents as well. Indubitably, water pollution and its health impact remain enormous challenges in China.