【作者】 何欣；

【导师】 全燮；

【作者基本信息】 大连理工大学 ， 环境工程， 2009， 博士

【摘要】 东北地区是我国重要的工业基地和粮食基地,工业污染和农药污染比较严重。该地区也是我国主要产油区,主要有大庆、辽河和吉林三大油田,石油在开采、运输等过程中不可避免地污染土壤。东北地区纬度较高,冬季较长,一般从11月到次年2月,平均气温较低,最低气温可达到-35℃。本论文研究了东北受污染土壤中,挥发（VOCs）、半挥发性有机污染物（SOCs）在低温和油复合污染时的土/气分配行为。具体开展了以下研究:（1）采用批实验的方法,以三氯乙烯（TCE）为代表,测定了TCE在有机碳含量不同的土壤上（黄土、稻田土和黑土）,各种温度下（-14-20℃）的土/气分配系数(K_SA)。TCE的K_SA随着土壤有机碳含量增加、温度降低而增大。在低温情况下,即使是挥发性极高的TCE也可以更趋于分配到土壤中(-14℃,K_SA=10³)。（2）为了进一步研究化合物在低温下的土/气分配行为,采用固相逸度计的方法,以半挥发性的Aroclor1242为目标物,测定66种多氯联（PCBs）（其中27种为色谱上的共流出物）,在-30-30℃范围内,15个温度下的K_SA,跨近6.5个数量级,范围在10^4.4-10¹¹。在温度≥0℃和温度≤0℃时,PCBs的log K_SA与绝对温度的倒数均呈线性关系,斜率分别在3.82-5.61和5.58-6.88之间。说明PCBs的log K_SA随温度的降低而显著增大,而在温度<0℃时,这种增大的趋势更为显著。实验测定的log K_SA与相应的log K_OA线性回归后的斜率接近于1,说明PCBs在土壤上的分配性质与其在辛醇上的分配性质相似。改进的Karickhoff方程被成功地用来预测PCBs在实验土壤上的分配（温度≥0℃和温度≤0℃）。（3）为了进一步扩展低温下SOCs的K_SA数据,测定了2种多环芳烃（菲和荧蒽）和6种有机氯杀虫剂（α-六六六、γ-六六六、顺式氯丹、o,p’-滴滴伊、反式氯丹和反式九氯）在-30-30℃温度范围内的K_SA,得到113个数据,范围在10^4.5-10^10.4。与PCBs的结果相同,在温度≥0℃和温度≤0℃时,这些物质的log K_SA与绝对温度的倒数均呈线性关系。温度≥0℃,PAHs和OCs的斜率分别在4.11-4.84和4.75-5.65之间;而当温度≤0℃,PAHs和OCs的斜率则分别在5.51-6.10和6.23-9.68之间。各测试温度下OCs的log K_SA和log K_OA线性回归后的斜率均值为0.6。进一步研究表明,Karickhoff方程只能大体上估测OCs在实验土壤上的K_SA,20℃时,预测值最大是实测值的19倍（反式九氯）。（4）结合东北地区油污染的特点,考察了油-六氯苯（HCB）复合污染土壤中,不同油浓度和温度（-30-30℃）下HCB的K_SA。在考察油浓度影响的实验中得出:20℃时,在有机碳含量为1%的土壤中,盘锦原油的临界独立相浓度（CSPC）约为1000 mg kg^-1,当大于该值时,油以体相存在于土壤。在温度影响实验中得出:油污染的土壤中,油对土壤吸附（分配）性能的改变与温度有关,相同油污染负荷的土壤,高温时油更趋于增强整体土壤的吸附（分配）能力,并且与土壤天然有机碳相比,油是一种吸附（分配）能力很强的基质,30℃时是土壤天然有机碳的5倍。总之,本研究在更宽的环境温度范围内,考察了部分有机污染物的土/气分配行为。揭示了低温（≤0℃）时,化合物土/气分配行为的特殊性。初步探讨了土壤中残留油对其他化合物土/气分配行为的影响。本论文填补了低温下分配数据的空白,进而加深了人们对化合物在低温及油污染土壤中环境行为的理解。更多还原

【Abstract】 The old industrial base in Northeast China is a major heavy industry and commodity grain base.Both manufacturing and agricultural enhanced the possibility of introducing contaminants into soil.Meanwhile,as the three terrestrial oil fields were in this region,the soils near the oil field were badly polluted during the processes of exploitation and transportation of oils.The old industrial base located in the northeastern China,has a long cold winter usually from November to February with the extremely temperature lower than -35℃.The present study was focused on the soil/air partitioning behavior of selected volatile organic compounds（VOCs） and semivolatile organic compounds（SOCs） under a frozen circumstance or in oil-complex contaminated soils.The study comprises of several parts as follows:（1） The soil/air partition coefficient K_SA for TCE was determined in batches in three soils, black soil,paddy field soil,yellow soil,with different organic carbon contents.The results showed that K_SA for TCE increased with organic carbon contents.For the strong temperature-dependence of K_SA,even for a volatile compound,TCE,could be tend to partition into the soil at lower temperature(-14℃,K_SA = 10³).（2） K_SA-values for 66 PCBs congeners（including 27 co-eluting congeners） in Aroclor 1242 were measured by fugacity meter method over -30～30℃.About 600 data were obtained,which ranged 10^4.4～10¹¹.Of all the PCBs tested,plots of log K_SA vs.T¹ exhibited two separate regression lines below and above 0℃,with the slope over 3.82～5.61 and 5.58～6.88 below and above 0℃,respectively.The larger slope below 0℃indicating the greater enhancement of K_SA with a decline of temperatures below 0℃,might caused by the decrease of soil relative humidity（RH） under a frozen circumstance.The slopes of linear regression between log K_SA and log K_OA were close to 1 implying that K_OA was a suitable surrogate for the partitioning properties of present soil.Furthermore two modified Karickhoff-type equations were introduced to fit values of K_SA for PCBs above and below 0℃,respectively.（3） To extend the database for K_SA at sub-zero temperatures,K_SA-values for phenanthrene（Phe）,fluoranthene（Flu）,α-hexachlorocyclohexane（α-HCH）,γ-hexachlorocyclohexane（γ-HCH）,trans-chlordane（TC）,o,p’-DDE,cis-chlordane（CC） and trans-nonachlor（TN） were also determined by the same method as PCBs over -30～30℃.As observed by PCBs,for these compounds plots of log K_SA vs.T¹ also exhibited two separate regression lines below and above 0℃,with the slope from 4.11 to 4.84 for the PAHs and from 4.75 to 5.65 for the OCs above 0℃.And K_SA became more sensitive to the temperature below 0℃,with the slope from 5.51 to 6.10 for the PAHs and from 6.23 to 9.68 for the OCs. The average slope of linear regression between log K_SA and log K_OA at different temperatures was 0.6 for OCs and K_OA-based Karickhoff equation could be used to roughly estimate the K_SA for OCs.（4） Considering that oil contamination is one of the most important environmental problems in the northeastem China,K_SA for hexachlorobenzene（HCB） was determined in an artificially HCB-oil complex contaminated soil at different oil contents and temperatures.The results showed that the critical separate phase concentration（CSPC） for a crude oil from Liao River oil field in the soil with 1%organic carbon content was about 1000 mg kg^-1.As compared to the natural organic carbon,oil is a supersorbent for HCB,with the ratio of （oil/air partition coefficient）/（organic carbon/air partition coefficient） from 5 to 1 when temperature decreased from 30 to 5℃In conclusion,measurements of K_SA for selected VOCs and SOCs were carried out over a wide relevant temperature range.With the experimental data below 0℃,the partitioning behavior of the selected SOCs was discussed.Meanwhile,the partitioning behavior of SOCs in oil-contaminated soils was also investigated.This work attempts to close the gap of partitioning data at subzero temperatures and thereby expands our understanding of the environmental behavior and fate of organic chemicals in a low-temperature environment.更多还原