Study On The Pollution Characteristics And Environmental Risk Assessment On The Heavy Metal Of The Particles In The Pearl River Delta

In order to understand Heavy Metals Pollution and harm of atmospheric particulate matter PM₁₀ and PM_2.5 In the Pearl River Delta region, this paper treated The Pearl River Delta city group（Guangzhou, Shenzhen, Zhuhai, Zhongshan, Jiangmen, Zhaoqing, Foshan, Huizhou） as an object of study, besides, PM₁₀ and PM_2.5 samples were collected. ICP-MS was used to analysis the content value of heavy metals（Pb, Ni, Cd, Cr, As, Sb） in PM₁₀ and PM_2.5, we also used correlation coefficient method and principal component analysis method to analysis roμghly source of heavy metals of Guangzhou winter PM₁₀ and PM_2.5. Cumulative index, potential ecological risk assessment and health risk assessment were also used to evaluate the degree of harm of Heavy Metals of PM_2.5 in the atmosphere in the Pearl River Delta city group. The main findings are as follows:（1） Compared with the background point（Wuyishan）, the heavy metals of PM₁₀ and PM_2.5 were from 1.50 to 6.50 and from 1.01 to 6.80 times the background points, respectively. Taken together, Foshan and Dongguan atmospheric heavy metal pollution is more serious, less Zhuhai and Huizhou atmospheric heavy metal pollution. This may be because Foshan which is the typical ceramics manufacturing base and Dongguan which has the largest thermal power plant group of the China and has a lot of paper and textile enterprises consume a large amount of coal burning, causing atmospheric heavy metal pollution. However, Zhuhai and Huizhou which close to the Pearl River estuary are tourist cities, their geographical location and economic structure to ensure its air quality.（2）Principal component analysis showed that traffic pollution, coal fuel combustion, metal smelting industry is the main source of heavy metals in the ambient air of Guangzhou winter. Its contribution rate in the PM₁₀ and PM_2.5 were 54.2%, 16.8%, 14.1% and 50.9%, 19.3%, 16.9%.（3）The concentration of each eavy metal has small proportion in the particulate matter(PM₁₀ and PM_2.5), except for winter Pb particles in the proportion of higher than 10-3, other elements are less than 10-3, because of its toxicity, human health effects can not be ignored. It is different in terms of elements, Pb and Ac relatively has higher proportion, while Cd has the lowest percentage. For different cities, heavy metals of particles in Guangzhou has the highest proportion, followed by Dongguan, Huizhou is minimum.（4）Land accumulation index calculated that the accumulate Igeo index values of Cd、As and Sb of PM_2.5 in the summer in Pearl River Delta city group were greater than 2, pollution levels were up to three, that was moderate pollution, and the pollution levels of Cd in Zhaoqing and Foshan were up to 4, that was emphasis on pollution; the accumulate index Igeo value of Pb were between 1 to 3, the degree of pollution is moderate or moderate migraine; the accumulate index Igeo value of Ni and Cr were the small, pollution levels were mild to moderate migraine. The environmental pollution in the Pearl River Delta in winter is similar to the summer.（5）Potential ecological risk assessment showed that in the PM_2.5 in Pearl River Delta city group: Cr potential ecological risk index value IR <150, ecological hazard degree are slight; Potential ecological risk index value of Ni was between 150 and 300, ecological hazard degree was mild or moderate; Pb potential ecological risk index value IR> 300, hazard level is medium or above medium; Cd, As and Sb potential ecological risk index values are greater than 1200, the degree of harm was maximum Overall potential ecological risks of the cities showed a strong trend.（6）According to the study population of Pearl River Delta city group, non-carcinogenic health risk value of the sum（HI） of 6 kinds of heavy metal elements（Pb, Sb, As, Cr, Cd, Ni） was in 8.86 × 10-3 2.59 × 10-1, they were all less than 1. It means that the metals less has impact on human health can be ignored. 4 kinds of carcinogenic heavy metals As, Cr, Cd, Ni cancer risk value CR were 8.03×10-5¹.66×10-4, 3.89×10-5⁸.52×10-5,9.06×10-7⁸.20×10-6,2.09×10-7¹.44×10-6. In addition to cancer risk values of carcinogenic Heavy Metals As in excess of the threshold value（10-6 to 10-4） for study people in Guangzhou, Dongguan, Zhongshan, Jiangmen and Foshan, the cancer risk of 3 kind of other carcinogenic elements did not exceed the threshold in the city.