| BackgroundThe waste of non-ferrous metal production process contains a large amount of harmful elements and heavy metals.In our country, non-ferrous metal pollution is widely spreaded,especially around the non-ferrous metal mines. The pollution has a bad impact on the residents. For example,Arsenic, cadmium, chromium are I class carcinogens identified by the International Agency for Research on Cancer (IARC),to which the long-term exposure can increase the victim’s cancer risk. Research has shown that the cancer mortality of arsenic poisoning patients is significantly higher than that of the normal group, with the relative risk (RR)9.13and population attributable risk (PAR)89.04%.Also, arsenic exposure population is more likely to suffer from skin lesions (Spearman coefficient rs=0.501, P<0.05).Other non-ferrous metals pollution may lead to high blood pressure,cardiovascular disease,diabetes, bronchiectasis etc.. Environmental pollution caused by a variety of non-ferrous metal pollutants also has bad impacts on victims,significantly increasing the victim’s total mortality. While,there are still some studies that have the opposite results, that is, the As pollutants such As did no harm to humans.So whether the non-ferrous metal pollution do a harm to human body is still a problem.ObjectiveTo understand the distribution of mortality in the study area,and to analyse the influence of the non-ferrous metals pollution on the mortality and heath,thus to provide clues for the causes of death in this area,and to provide the reference for health policy and strategies made by the local health administrative department. MethodsIn this study, the ecological comparison research was performed, during which ARMA model was first used to forecast the non-accident mortality of this area in the future, and then comparison between polluted area and control area,or comparison between different buffers was made and correlation between mortality of disease in different towns and the distance from the minesto the town was explored. Software SAS9.2and EXCEL were mainly used for analysis and software ArcGIS10.0for mapping and buffer analysis.ResultsMA (1) model (xt=35.07217+(1+0.4757B)*εt) fitted the mortality rate of the study region well, with the predicted mortality rate of October32.65per100thousands, November35.07per100thousands,December32.65per100thousands in2012, and the average relative eRRor12.25%. The predicted non-accident mortality in January2013was35.07/100per thousands.The average ajusted mortality of heart cerebrovascular disease, malignant tumor, and digestive system disease in the study area were248.32per100thousands,127.63per100thousands,23.41per100thousands,respectively,all significantly higher than those in the control area(231.51per100thousands,119.73per100thousands,17.88per100thousands).While,the ajusted mortality of respiratory system disease in control area(85.33per100thousands) is significantly lower then that in the study area(105.80per100thousands).As to the trend,for non-accident and respiratory system disease,there exist trends that mortality in study area is lower than those in the contol area;meanwhile,for cancer,there exists a trend that mortality in the study area is higher than that in the control area.A correlation between the distance from the mines to the town and the mortality of cancer in the towns in the study area was indeed exsited,and the pearson correlation coefficient r=-0.539, P=0.017<0.05.It shows that there was a higher cancer mortality for the area closer to the mine.Buffer analysis on three mines showed that standardized mortality of cancer in the5km buffer was significantly higher than those in the other buffers;the cancer mortality in the10km buffer significantly higher than that in the>10km buffer,.P<0.0167.That means that there was higher cancer mortality in the area closer to the mines.To explore the diameter in which the risk of cancer maximize, we compare the cancer mortality in the internalbuffer with that in the external buffer,and found that it was when in a5km radius that RR reached the maximum.Compared with5km external buffer, cancer RR in the5km buffer was1.21(in total,95%CI:1.10～1.33),1.15(male,95%CI:1.03～1.29),1.34(female,95%CI:1.14～1.57);lung cancer RR1.29(in total,95%CI:1.08～1.54),1.28(male,95%CI:1.04～1.57),1.35(female,95%CI:0.96～1.90), liver cancer RR1.29(in total,95%CI:1.06～1.57),1.32(male,95%CI:1.06～1.65),1.19(women,95%CI:0.77～1.82).Buffer analysis on two main mines showed that standardized cancer mortality in5km buffer was significantly higher than those in other buffers.Although the difference of average cancer standardized mortality between5km buffer and15km is not significant, there exist a trend that the there was a a higher cancer mortality in the buffer closer to the mines.Comparing the cancer mortality in the internalbuffer with that in the external buffer,we found that it is in a5km radius that RR reached the maximum.Compared with5km outside buffer, RR of cancer in5km buffer was1.28(in total,95%CI:1.15～1.43),1.28(male,95%CI:1.12～1.46),1.30(female,95%CI:1.08～1.56), lung cancer RR1.51(in total,95%CI:1.24～1.83),1.61(male,95%CI:1.29～2.02),1.22(female,95%CI:0.82～1.83), liver cancer RR1.37(in total,95%CI:1.10～1.72),1.46(male,95%CI:1.14～1.87),1.10(female,95%CI:0.66～1.84).The average standardized mortality and RR (men and women combined, men and women) of cancer, lung cancer and liver cancer,in the5km buffer of two main mines were all higher than those in the5km buffer of three mines.In5km buffer both of the main mines and three mines, the average standardized mortality of cancer lung cancer, liver cancer in male were all higher than those in female, but the difference was not significant.ConclusionsCancer risk in the study area is significantly higher than those in the control area,while the respiratory system disease risk is significantly lower than that in the control area. In the study area, the average cancer standardized mortality in different towns is related with the distance from the mines to the town.The closer the town is to the mines.the higher the cancer standardized mortality is. Generally, compared with the peripheral buffer, when the internal buffer radius is5km,the cancer risk is the largest. The average standardized mortality of cancer,lung cancer and liver cancer, in the5km buffer of two main mines were higher than that in the5km buffer of three mines;In5km buffer both of the main mines and three mines,the average standardized mortality of cancer,lung cancer and liver cancer in male were all higher than those in female, but the difference was not significant. |
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