辽河口苇田湿地PAHs分布及源解析复合受体模型研究

发布时间：2017-12-26 23:28

本文关键词：辽河口苇田湿地PAHs分布及源解析复合受体模型研究　出处：《中国海洋大学》2015年硕士论文　论文类型：学位论文

【摘要】：持久性有机污染物,因具有持久性、生物毒性、生物富集性、远距离迁移性及三致作用(致畸、致癌、致突变)等,成为近年来世界关注的焦点,研究人员对其开展了大量的研究。本文利用GC/MS测定了辽河口苇田湿地土壤中16种优控PAHs的含量,阐述了PAHs在土壤中的分布情况,讨论了土壤中PAHs分布的影响因素,研究应用正定矩阵因子分解模型(PMF)、Unmix和化学质量平衡模型(CMB)三种单一模型及Unmix-CMB复合受体模型解析土壤中PAHs的来源,并将模型进一步与毒性当量(TEQ)结合以定量地估算了PAHs污染来源的毒性贡献。该研究对于从源头对湿地土壤中PAHs进行有效地控制具有重要的意义。湿地土壤中PAHs含量范围为235-374 ng/g,平均值为287 ng/g,处于轻微污染水平。PAHs的含量尤其是低环PAHs分布更容易受到土壤有机碳的影响,土壤粘粒含量对PAHs浓度的分布也有一定关系,而阳离子交换量则主要对中高环PAHs的分布有一定影响。在土壤不同水稳性团聚体中PAHs的分布中,PAHs含量随着团聚体粒径的减小而减少,土壤中较大粒径的团聚体对低分子量PAHs的吸附相对较强。利用高低分子量比值及同分异构体比值法初步推断,苇田湿地土壤中PAHs的来源主要有石油产品燃烧和生物质燃烧等燃烧源以及石油的泄露等。进一步对土壤中PAHs进行定量源解析,PMF模型解析结果显示,石油源(31%)、汽油发动机排放(26%)和柴油发动机排放(23%)和生物质燃烧(20%)为土壤中PAHs的主要来源；Unmix模型解析结果表明,石油源的贡献最大,达到了43%,汽油机和柴油机排放源的贡献率为35%,生物质燃烧也有一定贡献,贡献率为22%；CMB模型源解析结果表明,汽油发动机排放(29%)与柴油发动机排放(28%)的贡献最大；生物质燃烧和石油类产品的输入对辽河口苇田湿地土壤中PAHs也有较高贡献,贡献率分别为21%和22%；这些污染源跟苇田湿地附近的人类活动诸如交通排放、烧荒和油田开采等有密不可分的关系。本文对PMF、Unmix和CMB三种模型的解析结果进行了对比,结果显示,三种模型各自解析得到的PAHs模拟值与实测值的拟合均表现良好,CMB模型比PMF和Unmix的拟合优度稍高,但其误差百分数绝对值普遍比PMF和Unmix大,PMF和Unmix模型得到的模拟值也非常接近；CMB模型对土壤中PAHs来源贡献存在低估的问题：由于共线性问题的存在,Unmix将汽油机和柴油机排放源作为一个因子提取出来；三种模型解析出石油源、柴油机和汽油机排放源在贡献率上存在一定差异,而生物质燃烧源的贡献率差别不大,这可能与模型自身的算法及参数的选择等有较大关系。为了解决Unmix模型解析过程中的共线性问题,本文进一步构建了Unmix-CMB复合模型,其解析结果显示,PAHs的主要来源依次为石油源(43%)、汽油发动机排放(23%)生物质燃烧(22%)和柴油发动机排放(12%)。为了解不同来源的毒性效应,本文将上述受体模型与毒性当量(TEQ)结合起来,PMF-TEQ、Unmix-TEQ、 CMB-TEQ及Unmix-CMB-TEQ的毒性解析结果表明,汽油机和柴油机排放源呈现出最高的毒性贡献,贡献率分别为64%、61%、96%和63%,表明汽油机和柴油机排放具有最大的毒性效应,PMF-TEQ与Unmix-CMB-TEQ在毒性贡献率上表现出非常相似的结果；石油源和生物质燃烧在PMF-TEQ、Unmix-TEQ和Unmix-CMB-TEQ的解析结果中也呈现出一定的毒性贡献,而在CMB-TEQ的结果中其毒性效应基本可以忽略,这些结果的差异跟模型之间的差异紧密相关。
[Abstract]:Persistent organic pollutants (persistent organic pollutants), which are persistent, biotoxic, bioaccumulation, long-distance migration and three effects (teratogenicity, carcinogenesis, mutation), have become the focus of world attention in recent years, and researchers have done a lot of research on them. The contents of Liaohe estuary reed wetland soil and the determination of 16 kinds of PAHs control using GC/MS, expounds the distribution of PAHs in soil, the factors affecting the distribution of PAHs in soil is discussed, application of positive matrix factorization model (PMF), Unmix and chemical mass balance model (CMB) three sources the single PAHs model and the Unmix-CMB receptor complex model analysis in the soil, and the model is further and toxic equivalent (TEQ) combined with quantitative estimation of sources of PAHs toxicity contribution. The research is of great significance to the effective control of PAHs in wetland soil from the source. The content of PAHs in wetland soil is 235-374 ng/g, the average value is 287 ng/g, and it is at the level of slight pollution. PAHs content, especially low ring PAHs distribution, is more susceptible to soil organic carbon. Soil clay content also has a certain relationship with PAHs concentration distribution, while cation exchange rate has a certain effect on the distribution of PAHs. In the distribution of PAHs in different soil water stable aggregates, the PAHs content decreases with the decrease of aggregate size. The larger particle aggregates in the soil have relatively strong adsorption for low molecular weight PAHs. Based on the ratio of high and low molecular weight and the ratio of isomer, it is preliminarily deduced that the sources of PAHs in reed wetland soil are mainly petroleum products combustion and biomass burning and oil leakage. Further quantitative source apportionment of PAHs in soil, the analytical results of PMF model shows that the source of oil (31%), gasoline engine emissions of diesel engine emissions (26%) and (23%) and biomass burning (20%) as the main source of PAHs in soil; analytical results of Unmix model showed that the oil source contribution and reached 43% gasoline engine and diesel engine, emission contribution rate is 35%, biomass burning has certain contribution, contribution rate was 22%; CMB model source analysis results show that the engine exhaust emission of diesel engine (29%) and (28%) the largest contribution; biomass combustion and input of petroleum products also have a higher contribution to PAHs Liaohe estuary reed wetland soil, the contribution rate were 21% and 22%; the pollution source with reed wetland near human activities such as traffic emission, burning and oil etc. are closely related. The analysis of PMF, Unmix and CMB results of the three models were compared. The results show that the simulated three models each analytic PAHs values fit with measured values showed good, CMB model is better than PMF and Unmix goodness of fit is slightly higher, but the percentage error absolute value generally than PMF and Unmix that value is very close to the simulated PMF and Unmix model; CMB model underestimated problem of sources of PAHs in soil contribution: owing to collinearity problems, Unmix gasoline engine and diesel engine emission sources as a factor extracted; three model solution precipitation oil source, diesel engine and gasoline engine emissions there are some differences in the contribution rate, and biomass burning source contribution rate is not very different, it may have a greater relationship and its algorithm parameters and model selection. In order to solve the collinearity problem in the process of Unmix model resolution, the Unmix-CMB composite model is further constructed. The analysis results show that the main sources of PAHs are oil source (43%), gasoline engine emission (23%), biomass combustion (22%) and diesel engine exhaust (12%). In order to understand the toxic effects of different sources, the receptor model and toxic equivalent (TEQ) combined with the analysis of PMF-TEQ, Unmix-TEQ, toxicity of CMB-TEQ and Unmix-CMB-TEQ showed that the gasoline engine and diesel engine emission sources showing the highest toxicity contribution, the contribution rate of 64% and 61% respectively, 96% and 63%, showed that emissions has the biggest toxic effect of gasoline engine and diesel engine, PMF-TEQ and Unmix-CMB-TEQ in toxicity contribution rate showed very similar results; in the analytical results of PMF-TEQ, Unmix-TEQ and Unmix-CMB-TEQ also showed certain toxicity with oil source and biomass burning, and result in CMB-TEQ in its toxic effects can be ignored, the difference between these differences are closely related with the model.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X592

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