【作者】 李向阳；

【导师】 高宏；

【作者基本信息】 兰州大学 ， 环境科学， 2011， 硕士

【摘要】 有机氯农药(OCPs)作为一类典型持久性有机污染物(POPs)具有半挥发性、持久性、生物蓄积性以及高毒性,严重危害着人类和生态环境。建立其网格化清单,并以清单作为基础数据,模拟其在研究区域环境过程,对了解区域OCPs历史使用状况、归趋行为等具有一定的理论及现实意义。同时也可为区域污染控制与修复提供科学依据。目前甘肃省尚缺乏全省尺度相应的OCPs网格化清单及其归趋行为数值模拟的系统研究。本论文搜集整理了甘肃省相关OCPs历史使用数据,并以甘肃省1/4°×1/6°经纬度网格化旱田面积为替代数据,编制了甘肃省HCHs、DDTs以及硫丹网格化清单,总结并分析了甘肃省目标化合物历史使用情况及使用量较大的地区。此外,以α-HCH网格化清单为基础数据,运用环境多介质模型,对其在甘肃省土壤残留时空变化、源汇解析以及交换通量等区域归趋行为进行数值模拟研究。结论如下：(1)1952-1984年间,甘肃省共使用HCHs6.5万吨；1951-1984年间,共使用DDTs1.6万吨；1994-2007年间,共使用硫丹701吨。目标化合物使用量较大的地区集中在平凉、天水以及庆阳地区；小麦、苹果以及棉花是甘肃省硫丹施用的主要农作物。(2)模型输入与输出量相差80吨,误差仅为1.9%,表明模型有较好的质量守恒性；模型输出的残留数据与监测数据吻合较好,说明该模型对研究甘肃省有机氯农药的归趋行为具有较好的适用性；在各环境介质中：土壤是影响甘肃省α-HCH残留与降解的主要因素,而大气平流是其从研究区迁出的主要途径；α-HCH在水体底泥中降解及残留量较小。(3)α-HCH使用期间,甘肃省土壤残留量逐年增加,在不考虑其他省份α-HCH使用情况下,甘肃省α-HCH不仅可迁移到内蒙古,青海及四川的大部分地区,还可到达几乎没有使用过OCPs的西藏地区；停用后α-HCH在土壤中的残留量下降趋势明显,对其他地区的影响也逐渐缩小。(4)甘肃省α-HCH汇区主要集中在甘南地区和肃南县；而历史使用量较大的环县,以及蒸发作用强烈的安西、敦煌地区表现为源区；各介质交换通量结果表明：气-土交换主要以土壤向大气挥发为主,其次为大气向土壤的湿沉降,而大气到水体以及水体向底泥中沉积通量较小。更多还原

【Abstract】 Organochlorine pesticides (OCPs) are categorized as a typical group of persistent organic pollutants (POPs) which share some specific characteristics, such as semi-volatility, persistence, bioaccumulation and high toxicity. They pose a serious threat to human health and the ecological environment. It is significant for creating gridded inventory and simulating the fate of POPs using this inventory as the basic data, which can provide theoretical foundation to know the historical usage condition, to understand the fate of these chemicals and make policies to control and remediate the regional pollution. Now there is a lack of systematic studies on the gridded usage inventories and fate of OCPs in Gansu Province.In this paper, we compiled the relatively historical OCPs usage data and created the gridded usage inventories of HCHs, DDTs and Endosulfan in Gansu using a gridded dry land datasets with 1/6°latitude by 1/4°longitude resolution of Gansu Province as the surrogate data. Moreover, the most heavily usage regions and the crops of the target compounds in Gansu have been investigated. In addition, the temporal and spatial variability of soil pollution, the source-receptor relationship, the exchange flux and fate ofα-HCH have been simulated by a gridded environmental multi-medium model The conclusions can be summarized as follows:(1) According to the study, from 1952 to 1984,1951 to 1984 and 1994 to 2007 there were 65kt HCHs、16kt DDTs and 0.7kt endosulfan have been used, respectively. The major usage areas were centralized in Pingliang, Tianshui and Qingyang regions, meanwhile, endosulfan was mainly used for several crops such as wheat, apples and cotton, etc(2) The difference value between input data and output data of model was only 80t, namely, the deviation was 1.9%, which suggest that the model have a good mass conservation. Futhermore, the model output shows a good match to measured soil concentrations, it manifested that this model is well applicable to simulating fate of OCPs in arid and semi-arid Gansu area. In addition, the soil was major factor which impact residues and degradation ofα-HCH in Gansu area, meanwhile, atmospheric advection was the primary way forα-HCH to move out of Gansu, However, the residues and degradation in sediment were less than those of above mediums.(3) During the period of a-HCH usage period, residues residue levels in soil showed an increasing trend over time. In addition, considering no a-HCH usage in other provinces, the usage a-HCH in Gansu Province could transported and distributed on a large-scale area not only including Inner Mongolia, Sichuan Province and Qinghai Province but also including Tibet with almost no OCPs usage. But after banning, the range of influence areas become smaller year after year.(4) Gannan region and Sunan county were the major receptors, however, the higher usage region of Huan and the strong evaporation regions such as Anxi and Dunhuang showed as the major source regions. In addition, the exchange fluxes suggest that evaporation from soil to air was the major exchange behavior; the deposition from air to soil was following, meanwhile, the exchange fluxes form air to water and from water to sediment were less than those of above exchange behavior.更多还原