基于源区监测的西安市路面径流污染机制及污染负荷研究

Studies on pollution mechanisms and pollution load of urban road runoff are foundations for identifying pollution intensity of urban road runoff, building pollution prediction model, proposing pollution control measures and utilizing rainwater resource. The pollution mechanisms of traffic road runoff in Xi'an, a city with serious dustfall and water shortage at northwest China, is chosen as research objective in the proposed study. The influences of traffic pollution discharge, atmospheric dry deposition and atmospheric wet deposition on runoff pollution of traffic road with different surrounding land use, different traffic volume and different sweeping efficiency, are studied based on long-term and systematic source area monitoring of air dustfall, road sediment, rainwater and road runoff. Pollution mechanisms and pollution characteristics of traffic road runoff in Xi'an can be revealed. The migration and transformation rules of pollutants in road sediment build-up and runoff wash-off system are discussed. The mathematical model of road runoff pollution load can be established as well. In addition, impacts of sampling size on estimation accuracy of road runoff pollution can also be investigated by random sampling method. The results are useful for the government and can provide a scientific basis for developing environmental pollution control strategies, improving urban environment management, controlling urban water pollution and promoting the utilizing of rainwater resource.

对路面径流污染机制和污染负荷的研究是确定路面径流污染强度、建立污染预测模型、实践污染治理措施及进行雨水资源化利用的基础和依据。本研究以大气降尘严重、水资源短缺的西安市的交通道路作为研究区域，通过在径流污染源区对大气降尘、路面沉积物、雨水及路面径流进行长期、系统原位测试，研究交通源排污、大气干沉降、大气湿沉降对周边土地利用类型各异、交通量各异、道路清扫水平各异的城市交通道路路面径流污染的影响，探明西安市路面径流污染输入、输出机制，揭示路面径流污染特征及污染物在路面累积-径流冲刷系统的迁移、转化规律，建立路面径流污染负荷数学模型，并采用随机抽样法编程研究采样场次对径流污染研究结果的影响以便为相关研究合理确定采样场次提供依据。研究成果可为西安市路面径流污染控制和雨水资源化利用提供科学的参考，对完善城市环境管理、缓解城市水环境污染、改善城市生态环境质量具有理论价值和现实意义。

对路面径流污染机制和污染负荷的研究是确定路面径流污染强度、建立污染负荷预测模型、实践污染治理及进行雨水资源化利用的基础和依据。本研究基于对西安市大气降尘、路面沉积物、雨水及路面径流的长期、系统采样测试，研究了大气降尘、路面沉积物、路面径流的污染特征，探明了交通源排污、大气干沉降、大气湿沉降对城市交通道路路面径流污染的贡献率及污染输入机制；基于对13场径流过程全程采样测试，探讨了降雨特征及污染物赋存类型对路面径流污染输出的影响、初期冲刷效应的存在条件及程度；提出了不同交通量道路的径流污染负荷率，建立了径流污染负荷数学模型；采用随机抽样法编程研究采样场次及时间间隔采样法样品数量对径流污染研究准确性的影响，提出实测16场路面径流的EMC可使计算的径流年污染负荷的最大相对误差小于30%，时间间隔采样法样品数量大于13个或19个，估算EMC与EMC近似真值的最大相对误差分别低于30%或20%。