The Relation Between Respiratory Diseases And Heavy Metals In Air Particulate In Chengdu Area

According to the references, respiratory diseases incidence has been rising these years, especially in Chengdu city, which rises 44% per year. Respiratory diseases have been the most mortality there. It had been concluded that the pollution acts as the main factor explaining the high incidence of respiratory diseases. Most research limited in the gas pollution such as oxide and particulate itself, paying less attention to the toxic elements. Thinking the meteorology characteristic of Chengdu area, windless and inversion, basing on the fact that toxic elements of particulate enter human body through breath and effect respiratory tract, this paper observed the relationship between respiratory diseases and the toxic elements in the air particulate. Hope to find the elements which cause respiratory diseases, this paper would give a reference to the environment study, to help to promote people's health level.The Air Particulate Near the Surface(APNS) was collected in Chengdu area, and surveyed 22 elements contents, to be the sample which informs the elements distribution of air particulate. The medical cases of lung cancer and children asthma were collected to calculate the respiratory diseases incidence. This paper evaluated the relation between the distribution of air elements and the distribution of respiratory diseases both with the method of microcosmic and macrocosm. In macrocosm, this paper taking the whole Chengdu area as object, juxtaposed the elements and diseases levels among the six cities; In microcosmic, this paper focusing in a small area, the Chengdu downtown, cut it to be 93 squares(1km*1km), estimated the elements concentration and the respiratory diseases incidence in each square, and did Partial Least-Squares (PLS) regress between the elements and the diseases. The interrelation was found. To make sure the relation between them, three more experiments were done to examine the result, the particulate diameter analysis and the Particulate Matter in 10um(PM10), hair elements analysis, elements toxicological experiment.At first, because the APNS is coarse, and the air particulate is fine, so the diameter of APNS was survyed to make sure APNS includes fine particulate. Then, 13 PM10 samples were collected in APNS's same area, to survey the elements distribution of PM 10, comparing with the elements of APNS, to make sure the elements in APNS is the proper sample to the elements in the air particulate.Second, 4 special area were picked up according to the elements content and respiratory diseases incidence. The citizen and lung cancer patients hair samples were collected to comparing that the different elements condition of air environment and different diseases condition, do or do not effect in human elements distribution.Third, two elements toxicological experiments were done. (1) According to the previous conclusion, Hg was proven to promote the probability of lung cancer, so a Single Cell Gel Electrophoresis(SCGE) test was be done to judge the mutagenic Hg, further to judge the carcinogenicity of Hg. (2) Since papers had reported that part harmful elements in the air come from the combustion of organism, and smoking is one of the reasons that cause lung cancer, tobacco was chosen to be the example of organism to burn to survey the elements rates of ash and gas phase. Using a new geochemical method, the Element Ratio Method(ERM), 11 elements were surveyed in the ash and the cigarette sample, to show how much elements transfer to the air. Those elements would be one of the reasons that smoking cause cancer, and wold move to the air in other burning process.The conclusion include:(1) 17% APNS is fine particulate which could enter the deep respiratory passage, and store in human body, cause respiratory diseases. Many analysis methods showed that Hg,C d,P b,As in the APNS are relative to respiratory diseases, Hg could be one of the reasons which cause lung cancer.(2) The incidence of lung cancer and children asthma in Chengdu area have been rising 20% per year, corresponding Hg,C d,A s,P b concentrated in APNS reaching 58, 35, 20, 17 times of Clarke Value. The most medical cases incidence hanppened in Deyang district and least happened in Meishan, corresponding the elements content were high and low in Deyang and Meishan.(3) Hair analysis showed that the element content in human hair is changed according to the differnent air environment in districts. There is significant differences between Hg content in lung cancer patients hair and normal people hair, P<0.05.(4) The SCGE experiment showed the HgCH3Cl is mutagenicity, which means that it probably is carcinogenicity. The cigarette elements distribution rates of ash and gas phase experiment showed that about 90% Hg elment moved into the air during smoke, Hg could be a new reason of"smoking cause cancer".So, this paper believe that the elements leading by Hg, Cd, Pb, As are relative with the sufferance of respiratory diseases. Most of these elements are heavy metals. To hold down the content of these elements in the air must be one of the ways to prevent and cure respiratory diseases.