【摘要】：近幾十年隨著我國社會和經濟的高速發(fā)展,土壤污染問題變得越來越嚴重,對農產品質量、大氣質量、水的質量和人類身體健康都造成了很大的威脅。本文以2013年在太原市城區(qū)周邊采集得到的171個土壤樣品的重金屬、有機氯農藥(OCPs)和多環(huán)芳烴(PAHs)的實測值為數(shù)據(jù)來源,對土壤污染狀況進行研究。在對各污染元素的含量進行統(tǒng)計分析的基礎上,用相關分析、單因子指數(shù)、內梅羅綜合污染指數(shù)、景觀指數(shù)對重金屬的污染特征進行分析；對有機氯農藥和多環(huán)芳烴的異構體組成特征進行分析,并對比太原市與其他地區(qū)的污染程度；采用隨機森林模型,對重金屬、有機氯農藥和多環(huán)芳烴及綜合污染程度分別進行評價。得到的主要研究結果有：(1)太原市城區(qū)周邊土壤中重金屬元素含量介于山西省元素背景值和國家土壤標準二級標準值之間,而有機氯農藥和多環(huán)芳烴的含量均介于國家土壤一級和二級標準之間。太原市城區(qū)周邊土壤污染較輕,不是非常嚴重。(2)8種重金屬元素中,Hg元素的變異系數(shù)最大,為1.04；而變異系數(shù)最小的As元素也達到了0.33,可見太原市城區(qū)周邊土壤中各重金屬元素含量的空間差異性較大。(3)對重金屬元素的單因子污染指數(shù)和內梅羅綜合污染指數(shù)進行計算和分析發(fā)現(xiàn)：Cd和Hg元素的污染比較嚴重,單因子污染指數(shù)分別達到了2.4和4.72,綜合污染指數(shù)的平均值也達到了3.59,可見太原市城區(qū)周邊的土壤重金屬污染較為嚴重。(4)通過景觀指數(shù)對土壤重金屬污染空間分布情況進行分析,發(fā)現(xiàn)太原市城區(qū)周邊的土壤重金屬污染大部分屬于輕度和中度污染,且不同等級的斑塊連通性較好,空間差異性較大。(5) OCPs總量的中位數(shù)為70.43 μg/kg,變異系數(shù)達到了1.05。對土壤中有機氯農藥的各異構體進行分析發(fā)現(xiàn)：α-HCH、β-HCH、γ-HCH和δ-HCH分別占總HCH的13.88%、51.95%、11.47%和14.79%；(DDD+DDE)/DDT比值均值為0.75。(6)16種多環(huán)芳烴的總和的平均值為3574.12μg/kg。各多環(huán)芳烴有機物的變異系數(shù)都在1以上,二氫苊、葸和芘三種化合物的變異系數(shù)分別達到了2.35、2.05和2.04。對其物質組成進行發(fā)現(xiàn)分析發(fā)現(xiàn),致癌性化合物在PAHs總量中所占的比例較大,且污染多來自于化石燃料的不完全燃燒。(7)用隨機森林算法對土壤污染進行評價,結果顯示171個土樣中重金屬污染評價等級屬于1、2、3、4的樣點分別占總樣點的4.68%、87.13%、8.19%和0%,可見大部分屬于2級污染。其中31個土壤樣品中重金屬、有機氯農藥污染和多環(huán)芳烴污染等級屬于1、2、3、4的樣品個數(shù)分別為3、21和1,21、8以及18,6、0和2,1、2和9。由此可見,31個樣點中多環(huán)芳烴污染相對于有機氯農藥污染較為嚴重,并且兩種污染嚴重的樣點均集中在太原市西部的化工企業(yè)聚集區(qū)。
[Abstract]:With the rapid development of our society and economy in recent decades, soil pollution has become more and more serious, which poses a great threat to the quality of agricultural products, air quality, water quality and human health. Based on the measured values of 171 soil samples collected around Taiyuan City in 2013, the soil pollution was studied by using the measured values of organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) (PAHs). Based on the statistical analysis of the contents of each pollution element, the pollution characteristics of heavy metals were analyzed by correlation analysis, single factor index, Nemero comprehensive pollution index and landscape index. The isomer composition characteristics of organochlorine pesticides and polycyclic aromatic hydrocarbons (PAHs) were analyzed, and the pollution levels in Taiyuan and other areas were compared. Organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) were evaluated respectively. The main results are as follows: (1) the content of heavy metal elements in the soil around Taiyuan City is between the background value of Shanxi Province and the national soil standard. However, the contents of organochlorine pesticides and polycyclic aromatic hydrocarbons (PAHs) are between the first and second grade of national soil standards. The pollution of soil around Taiyuan City is relatively light and not very serious. (2) the coefficient of variation of Hg element is the largest among the eight heavy metal elements, which is 1.04; The As element with the smallest coefficient of variation also reached 0.33. It can be seen that the spatial difference of the contents of each heavy metal element in the soil around Taiyuan City is great. (3) the single factor pollution index of heavy metal elements and the comprehensive pollution index of Nemero are increased. The calculation and analysis showed that the pollution of the elements of CD and Hg was serious. The single factor pollution index reached 2.4 and 4.72 respectively, and the average value of comprehensive pollution index reached 3.59. It can be seen that the soil heavy metal pollution around Taiyuan City is serious. (4) the spatial distribution of soil heavy metal pollution is analyzed by landscape index. It was found that most of the heavy metal pollution in the soil around Taiyuan city was mild and moderate pollution, and the patch connectivity of different grades was better, and the spatial difference was great. (5) the median of total OCPs was 70.43 渭 g / kg, and the coefficient of variation was 1.05. The isomers of organochlorine pesticides in soil were as follows: 偽 -HCH, 尾 -HCH, 緯 -HCH and 未 -HCH accounted for 13.88%, 51.95% and 14.79% of total HCH, respectively, and the mean value of (DDD DDE) / DDT ratio was 0.75. (6) the sum of 16 polycyclic aromatic hydrocarbons (PAHs) was 3574.12 渭 g / kg. The coefficient of variation of polycyclic aromatic compounds (PAHs) was above 1, and the coefficients of variation of dihydroacenaphthene, anthracene and pyrene were 2.35 and 2.04, respectively. It was found that carcinogenic compounds accounted for a large proportion of the total PAHs, and most of the pollution came from the incomplete combustion of fossil fuels. (7) the random forest algorithm was used to evaluate the soil pollution. The results showed that the samples of 171 soil samples with the grade of heavy metal pollution were 4.68% 87.138.19% and 0%, respectively, and most of them belonged to grade 2 pollution. The number of heavy metals, organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) in 31 soil samples were 30.21 and 1C21 / 8, respectively. It can be seen that the pollution of polycyclic aromatic hydrocarbons (PAHs) is more serious than that of organochlorine pesticides (OCPs) in the 31 sample sites, and the two serious samples are concentrated in the chemical enterprise accumulation area in the western part of Taiyuan.
【學位授予單位】：山西大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：X53;X825

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本文編號：2254100