| ObjectiveThe ecological study was to investigate the cancer incidence of areas polluted by PCP inSchistosomiasis endemic areas, and to explore the cancer risks of long-termenvironmental exposure to PCP in general population based on the data ofpentachlorophenol residues from raw drinking water.MethodsIncident cancer cases from2009to2012were identified using national registry andcomplemented by interviewing with each community healthy service centre. Crudecancer incidence rate and age-standardized rate was calculated by sex, cancer sites andage respectively. Besides, PCP concentration of water samples in each district wasmeasured by gas chromatography-tandem mass spectrometry(GC-MS/MS) analysis forfurther division of three environmental PCP exposure categories (High exposure group,Medium exposure group and Low exposure group) by the inter-quartile range. Crudecancer incidence rate and age-standardized rate of the three exposure groups was alsocalculated by sex, cancer sites and age respectively. And internal comparisons wereperformed and Standardized incidence ratios (SRRs) with95%confidence intervals(95%CIs) were applied to describe the relationship between PCP exposure and cancerrisks with low exposure group as the reference. ResultsFrom2009to2012, the total cancer incident cases were6750, the average crude cancerincidence rate was233.10/105(298.14/105in male and165.20/105in female), theage-standardized rate was123.77/105(147.78/105in male and93.03/105in female).Incidence in male was higher than that in female. Additionally the cancer incidenceincreased with age in those over50years old, which was particularly high in the oldwith over70years old. The top five common cancers were gastric cancer, lung cancer,esophagus cancer, colorectal cancer and liver cancer. The incidence of gastric cancerwas highest in both male and female.The water samples were extracted by solid phase extraction (SPE) and analyzed byGC-MS/MS. The assay was linear from0.1~1000μg/L and linear correlation coefficientwas0.9996. The limit of detection was1ng/L. The recoveries of standard addition were91.9%~109.0%and the relative standard deviations (RSDs) were all less than5%. All27water samples were collected and PCP was detected in every samples ranging from11.21to684.00ng/L.The incidence of high exposure group was remarkably high than the other two exposuregroups. Internal comparisons showed that SRR of medium exposure group was1.05(95%CI=1.01~1.10), while SRR of high exposure group was1.67(95%CI=1.60~1.74).Most SRRs of cancers increased with the elevated exposure grade from medium to high,relative to low. Particularly, leukemia (from3.95to18.83) and brain tumor (from2.04to4.09) in male, malignant lymphoma (from9.03to35.05) and esophagus cancer (from1.05to3.60) in female increased significantly. Besides, the SRRs of cancers in two agegroups of high exposure group were higher than that in the medium exposure group.And except lung cancer and liver cancer, the SRRs of malignant lymphoma,gastrointestinal cancer and breast cancer were on the rise significantly with the ageincreased. ConclusionsDigestive cancers and lung cancer occupied the most of the cancers occurring in the city.Gastric cancer should be the focus of the cancer monitoring and control. Middle-agedand elderly people were high risk groups of cancer, thus the healthcare of them shouldbe reinforced.SPE-GC/MS/MS is easy to operate with high recovery rate in the determination of PCPin water samples. The effect of this method was good in the practical application and itwas applicable for the qualitative and quantitative analysis of PCP.Long-term environmental exposure to PCP was probably associated with hemolymphneoplasm, digestive system neoplasm and neurologic tumors, especially for malignantlymphoma, leukemia and esophagus cancer. The health risks of long-term exposure toPCP were not negligible. |
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