化工开发区突发性大气污染事故预测预警系统建设架构

大气污染事故预测预警系统主要包括污染气象模型和大气扩散数学模型,利用地理信息系统(GIS)技术,按照污染事故发生的地理位置,将模型的数值解和GIS相结合,从而可以在时间和空间上对污染扩散进行分析,得到不同地点的污染物浓度和污染程度,获取受污染范围内的人口和周边单位等重要信息,从而预测污染事故对环境的影响程度和范围,为突发性环境污染事故的应急监测、现场救护和灾后评估提供科学依据。     

污染物在土壤中运移模型的研究进展

土壤中污染物运移的研究直接影响到环境科学的进展,常采用建立数学模型的方法预测污染物在土壤中的运移.文章系统地回顾了20多年来污染物在土壤中运移的数学模型研究进展,并根据模型的功能分为几何模型、对流-弥散传输模型(CDE)、随机模型三类.同时,对各类模型的特点、适用条件和存在问题进行比较分析,为有效地预测和控制污染物在土壤中的运移提供理论依据.     

NARX神经网络模型在昆明市环境空气质量预测中的应用

神经网络模型作为一种重要的手段被广泛应用于数学计算、物理建模、水文模拟、环境预测、人工智能等研究领域。为验证神经网络模型在高原山地城市环境空气质量预测中的作用,以昆明市环境空气自动监测站气象因子和污染物浓度数据为基础,构建NARX神经网络模型,对污染物浓度进行预测。结果表明,基于NARX神经网络建立的预测模型具有很强的非线性动态描述能力,能够对环境空气6参数做出较为准确的预测,其预测浓度相对误差显著低于CMAQ、NAQPMS空气质量数值模式以及LSTM统计模型预测结果。优化后的NARX神经网络对污染物浓度变化趋势的预测较其他几个模式更为敏感。     

水体突发性重金属污染胁迫下斑马鱼的行为反应分析

研究了斑马鱼在不同程度突发性的Zn2＋和Cr6＋胁迫下的行为反应,采用计算机视觉技术量化研究斑马鱼游动行为数据。结果表明,在Zn2＋和Cr6＋的突发性胁迫中,斑马鱼的行为反应快速且敏感,游动行为与污染物种类、质量浓度和暴露时间直接相关,并表现出比较相似的行为变化规律;随着胁迫程度的增加,斑马鱼游动速度的变化幅度增大,反应时间缩短,且其变化曲线符合生物行为的环境压力模型。斑马鱼的行为变化远远提前于生物的病理损伤或死亡,可利用斑马鱼暴露于污染物时的行为变化实现在线水体突发性重金属污染事故的监测预警。     

箱式模型在杭州市区预测SO_2地面浓度的应用

预测大气环境中污染物浓度的方法较多 ,箱式模型适用于排出源分布较为均匀或系统内部扩散信息难以得到的场合 ,从广度上讲是一种广域的污染状态模型。为解决箱内污染物浓度分布问题 ,将箱式模型进行改进 ,即假设混合层中污染物为均匀分布。另外由于模型本身较粗 ,而且假设较多 ,因此还必须作适当的修正。现采用修正后的箱式模型来预测杭州市区二氧化硫环境浓度。1　修正后的箱式模型　　Ｃｘ =ＰｘＬ·Ｈ·Ｖ Ｋ (1 )　　Ｋ =Ｃ0 - Ｐ0Ｌ·Ｈ·Ｖ (2 )式中 :　Ｃｘ、Ｃ0 ———计算年、基准年污染物浓度 ,ｍｇ/ｍ3;Ｐｘ、Ｐ0 ———计算年…     

基于去耦合直接法的兰江流域地表水水质预测方法研究

针对影响因素众多、耦合机制复杂情况下的地表水污染物浓度预测问题，将河道污染物浓度的变化量表示为各种影响因子一阶偏导项和二阶偏导项的线性叠加。其中，一阶偏导项可描述影响因子变化与污染物浓度变化的直接关系，二阶偏导项可描述影响因子之间交互作用对污染物浓度变化的影响。在此基础上，提出了用以模拟地表水污染物浓度的去耦合直接法。采用2014—2016年兰江流域将军岩、低田、半潭、沈村、焦岩5个断面的水文和氨氮、高锰酸盐指数、总氮、总磷4项污染指标逐日实测数据，通过差分法求解了一阶和二阶偏导项，并采用2017—2019年实测数据对模型进行了验证和评价。结果表明：去耦合直接法能够有效预测地表水主要污染物浓度的变化方向和变化量，且模拟结果和实测结果的符合情况较好，4项污染指标模拟值的Nash-Sutcliffe系数为0.479～0.654,模拟值与实测值的偏差为0.070～0.352;汇流区面积增加后，影响因子不确性对污染物浓度的扰动减小，污染物浓度变化的规律性增强，去耦合直接法的模拟精度升高。与SWAT模型的对比分析结果显示，在污染成因不发生显著变化的情况下，去耦合直接法的模拟精度优于SWAT模型。     

平原河网区水源地异味物质应急监测案例分析

平原河网区河流纵横交错，污染物质的迁移途径复杂多变，其内水源地突发性污染事故的应急监测难度大。以江苏省近期发生的一起水源地污染事故为典型案例，分析了污染物浓度沿程的变化特征以及典型断面污染物浓度的变化特征，总结事件处置的经验，为同类事件的处理提供借鉴。     

线性修正趋势分析技术在环境质量预警预测中的应用

线性修正趋势分析法根据历年数据建立线性模型并进行修正,预测年度、季环境要素污染物变化情况,可应用于空气质量、水环境质量、噪声环境质量、污染源污染物排放等预警预测数据统计分析评价,为环境决策提供技术支持。本文通过实例论述了该方法在实际工作中的应用。     

应用数据挖掘算法预测台风条件下PM_(2.5)质量浓度

利用6种数据挖掘算法对2012年台风和污染物浓度等数据建模,建立台风条件下的气象因素和环境空气中PM2.5的关系模型。通过对2013年数据的测试,表明6种数据挖掘方法模型的预测值与实测值具有很好的一致性。6种算法均能实现实时预测,其中Bagging算法预测结果的相关性整体最好,而对于测试样本,M5Rules算法最好,SMOreg算法次之。以2013年的超强台风"海燕"的预测为例,讨论台风条件下PM_(2.5)质量浓度的变化过程及对预测结果的解释。     

江苏响水爆炸事件环境应急监测工作几点思考

2019年3月21日,盐城市响水县陈家港化工园区的江苏天嘉宜化工有限公司发生爆炸事故,江苏省环境监测力量于事故发生后第一时间奔赴现场开展应急监测。通过收集和整理事故发生后环境应急监测工作的详细开展过程、事故现场污染物浓度变化数据,评估了事故应急处置期间污染物对周边环境的影响情况;通过对应急监测的工作措施进行简要分析,总结了应急监测工作在突发性环境污染事件中的作用与影响;指出该事故中监测机构应急监测技术能力的瓶颈和不足,并从根本上为提高应急监测能力提出建议。     

Simulation of the migration and transformation of petroleum pollutants in the soils of the Loess plateau: a case study in the Maling oil field of northwestern China

We developed a coupled water–oil simulation model to simulate the migration and transformation of petroleum-derived contaminants in the soil of the Xifeng oil field. To do so, we used the HYDRUS-2D model, which simulates the diffusion, adsorption or desorption, and microbial degradation of petroleum-derived hydrocarbons in the soil–water system. The saturated soil hydraulic conductivity of petroleum-derived pollutants was 0.05 cm?day^?1, which is about 1 to 2 % of the soil moisture permeability coefficient. Our numerical simulation results show that spilled crude oil was mainly concentrated in the surface horizons of the soil. The organic pollutant concentration tended to be highest nearest to the pollution source. The pollutant migration was generally concentrated within the top 20 to 30 cm of the soil, with the maximum concentration in the top 5 cm of the soil. With passing time, the pollutant accumulation increased and the adsorption and degradation functions reached a dynamic balance with the input rate at depths greater than 30 cm below the soil surface. The oil-derived pollutants totaled 50 to 100 mg?kg^?1 under the dynamic balance condition, which occurred after 20 to 30 years. The petroleum-derived pollutant concentration in the loess soil was inversely correlated with the horizontal distance from the oil well, and the concentration decreased greatly at a distance greater than 40 m from the well.     

Numerical Study of Hydrodynamic and Solute Transport with Discontinuous Flows in Coastal Water

This paper aimed to develop a depth-averaged explicit model for flow and pollutant transport in coastal waters based on the shallow water equations and the mass advection-diffusion equation. The proposed model was discretized using the finite volume method (FVM) with triangular cells. Then, it applied Roe’s approximate Riemann solution to compute the water momentum flux on the grid interfaces. This model enabled the higher accuracy in capturing the dry-wet moving fronts (discontinuous problems for flow and solute). The high-resolution scheme was evaluated to solve the advection and diffusion terms for mass transport. The model was verified by comparing the predictions of analytical solutions, laboratory tests, and other simulations for Gironde estuary with good computational accuracy. The developed model was also used to calculate the circulation and the motion of chemical oxygen demand (COD) pollutants from the sewage outfalls in the Zhuanghe coastal water with dry and wet moving boundaries. The research results showed that the residual current directions of spring and neap tides were basically the same in the Zhuanghe coastal water. However, the tide residual current of spring tide was slightly greater than that of the neap tide. In addition, there were tide residual currents from the northeast to the southwest in nearshore water and from the southwest to the northeast outside the banks, respectively. The tidal flows in the alongshore direction were strong, resulting in highly spread concentration distributions. In particular, the COD concentration reached some parts of the southern water. It could be seen that the excessive pollutant discharge from the sewage outfalls located at Zhuanghe district would cause serious pollution in aquaculture water near Shicheng island.     

太河水库水域总氮的纳污能力分析与总量控制

以太河水库主要污染物总氮为控制指标,选用适合于水域水环境特征的水质模型,对水域纳污能力、现状纳污量以及纳污削减量分别作计算.按照研究水域的功能区划和污染源分布与削减状况,分析并确定重点治理污染源,制定总量控制方案.     

水污染源源解析研究最新进展

采取有效措施监测监管污染物排放是实现污染减排目标的必要条件,而准确掌握流域内污染物的来源是实现污染源有效监管的技术依据,文章对水污染源源解析目标化合物选取、污染物扩散模型研究和污染区域受体模型研究的最新进展进行了评述,对其发展趋势进行了展望.     

淮河干流河南段水质预测模型试验研究

淮河干流在河南省境内总长417 km,随着区域经济的发展和人口的增长,淮河干流水环境质量形势不容乐观。根据水体扩散理论,建立了淮河干流水质预测相关模型,并进行了科学验证。对淮河干流河南段氨氮、化学需氧量衰减系数及富氧和耗氧系数4个项目开展现场试验及科学分析,为水资源保护规划中计算水体纳污能力、预测污染物浓度、制定污染物控制方案等提供坚实基础和技术支持。     

环渤海地区空气质量时空变化特征及动态预测

基于环渤海地区2017—2021年各城市空气质量指数(AQI)、污染物浓度与社会经济数据,利用数理统计、克里金插值法对环渤海地区AQI与污染物浓度的时空变化特征进行分析,运用皮尔逊相关性分析方法探讨AQI与污染物浓度、社会经济因素的相关关系,采用时间序列预测模型对2022年6月—2023年12月空气质量及污染物浓度进行预测。结果表明:环渤海地区AQI及污染物浓度大致呈逐年降低的趋势。AQI的逐月变化呈"W"形,O₃浓度的年内变化呈倒"V"形,其余污染物则呈现与O₃相反的变化趋势。AQI大致呈现西南高、东北低的空间分布特点,而污染物浓度分布具有明显的空间差异。环渤海地区5个代表性城市的AQI类别以良好为主,冬季首要污染物主要为PM_2.5、PM₁₀,夏季首要污染物以O₃为主。人口数量是影响AQI的主要因素,城市园林绿地面积对AQI具有一定影响。预测结果显示,未来环渤海地区AQI、主要污染物浓度(O₃除外)均呈现出随时间的推移逐渐下降的变化趋势。     

An Analytical Solution to Model Aquaculture Wetlands Subject to Intermittent Loading and Variable Initial Concentrations

Constructed wetlands are increasingly being used to treat intermittent releases of wastewaters from aquaculture ponds. Most constructed wetland design protocols are based on steady-state releases and as such are incapable of characterizing transient pollutant distribution arising from intermittent releases. Given the seasonal nature of aquaculture operations, the constructed wetland has to be developed using water from other nearby sources (termed as fill water in this study). In some instances, the pollutant concentrations in the fill water are noted to be greater than that measured in the aquaculture ponds. Also, the pollutants in the wetland may exhibit spatial variability due to geochemical interactions with wetland soils. These effects cannot be captured with existing steady-state design schemes. A mathematical model based on the tanks-in-series conceptualization is developed to overcome the aforementioned limitations. An analytical solution for multiple intermittent releases and spatially varying initial concentrations is obtained using Laplace transform and superposition techniques. The utility of the developed model is illustrated using an example based after a constructed wetland at the Loma Alta Shrimp Aquaculture Facility (LASAF) in South Texas. The developed model captures the extremely nonlinear relationship between the maximum discharge concentration and the hydraulic residence time. For the conditions assumed in this study, the extent of mixing is not of major concern when the spacing between the loadings is greater than 0.75 times the hydraulic residence time (HRT). Model results also suggest that the wetland should be oriented in a manner such that the internal geochemical production of the pollutant, if any, is near the inlet.