重金属在水体中的化学状态、危害及其防治对策

本文对目前研究最多的汞、铬、镉、铅和砷等重金属,详细分析了它们在水体中的迁移转化、价态变化、吸附与解吸附作用、吸附和共沉淀作用等动态过程;简要地阐述五种重金属对水体的污染给人体带来的危害;重点讨论了对水体重金属污染采取控制与消除土壤污染源、含重金属工业废水的排放和生物修复技术等防治对策。     

电动生物修复湖泊底泥中直链烷基苯磺酸钠

直链烷基苯磺酸钠(Linear Alkylbenzene Sulfonates,LAS)是环境中最常见的具有代表性的一类有机污染物,城市湖泊长期以来接纳了大量的污染物,致使底泥沉积了大最的LAS.采用电动生物复合技术修复东湖底泥中LAS,由于其LAS含量过高,当直接添加芽孢杆菌降解LAS时,发现无明显的降解效果.经过驯...     

Controlling cyanobacterial blooms by managing nutrient ratio and limitation in a large hypereutrophic lake: Lake Taihu, China

Excessive nitrogen (N) and phosphorus (P) loading of aquatic ecosystems is a leading cause of eutrophication and harmful algal blooms worldwide, and reducing nutrient levels in water has been a primary management objective. To provide a rational protection strategy and predict future trends of eutrophication in eutrophic lakes, we need to understand the relationships between nutrient ratios and nutrient limitations. We conducted a set of outdoor bioassays at the shore of Lake Taihu. It showed that N only additions induced phytoplankton growth but adding only P did not. Combined N plus P additions promoted higher phytoplankton biomass than N only additions, which suggested that both N and P were deficient for maximum phytoplankton growth in this lake (TN:TP = 18.9). When nutrients are present at less than 7.75-13.95 mg/L TN and 0.41-0.74 mg/L TP, the deficiency of either N or P or both limits the growth of phytoplankton. N limitation then takes place when the TN:TP ratio is less than 21.5-24.7 (TDN:TDP was 34.2-44.3), and P limitation occurs above this. Therefore, according to this ratio, controlling N when N limitation exists and controlling P when P deficiency is present will prevent algal blooms effectively in the short term. But for the long term, a persistent dual nutrient (N and P) management strategy is necessary.     

江苏省一次典型沙尘污染过程分析

2021年4月16日至4月18日江苏省经历了一次受沙尘影响的重污染过程.本次过程沙源地为蒙古国中南部及中国内蒙古中西部地区,在蒙古气旋后部西北大风影响下,沙尘气团自西北向东南影响了中国多个省市和地区.江苏省自16日起逐渐受到沙尘过程影响,苏北城市ρ(PM10)从凌晨开始迅速升高,浓度最高达569μg/m3,空气质量达严...     

曝气生物净化塘处理农村生活污水效果——以豫南地区商城县为例

为了提高农村生活污水治理效果的稳定性,同时考虑农村水生态景观建设需求,将具有强大调节能力的稳定塘技术、适合低浓度有机污水处理的接触氧化法和浅水湖泊草型清水稳态理论相结合,提出曝气生物净化塘工艺,应用于豫南地区商城县11个乡镇街区的农村生活污水处理,并选择其中4个典型案例运行1年的效果进行总结。结果表明:受乡镇街区的合流制排水系统、豫南地区多雨的气候特点及住户利用化粪池污水浇灌菜园习惯的影响,商城县各乡镇街区生活污水污染物浓度低且存在较大的波动性;曝气生物净化塘水力停留时间长,污水可在塘中完全混合,并形成适宜低污染物浓度净化的菌-草共生清水稳态系统,使净化后出水化学需氧量(COD_Cr)、氨氮(NH₃-N)、总氮(TN)、总磷(TP)指标均达到DB41/1820—2019《农村生活污水处理设施水污染物排放标准》一级标准,且出水COD_Cr、NH₃-N指标达到GB 3838—2002《地表水环境质量标准》Ⅳ类及以上水质标准。曝气生物净化塘适合低污染水平的农村生活污水的治理,且能形成清水型农村水生态景观。     

Potential of secondary aerosol formation from Chinese gasoline engine exhaust

Light-duty gasoline vehicles have drawn public attention in China due to their significant primary emissions of particulate matter and volatile organic compounds(VOCs). However,little information on secondary aerosol formation from exhaust for Chinese vehicles and fuel conditions is available. In this study, chamber experiments were conducted to quantify the potential of secondary aerosol formation from the exhaust of a port fuel injection gasoline engine. The engine and fuel used are common in the Chinese market, and the fuel satisfies the China V gasoline fuel standard. Substantial secondary aerosol formation was observed during a 4–5 hr simulation, which was estimated to represent more than 10 days of equivalent atmospheric photo-oxidation in Beijing. As a consequence, the extreme case secondary organic aerosol(SOA) production was 426 ± 85 mg/kg-fuel, with high levels of precursors and OH exposure. The low hygroscopicity of the aerosols formed inside the chamber suggests that SOA was the dominant chemical composition. Fourteen percent of SOA measured in the chamber experiments could be explained through the oxidation of speciated single-ring aromatics. Unspeciated precursors, such as intermediate-volatility organic compounds and semi-volatile organic compounds, might be significant for SOA formation from gasoline VOCs. We concluded that reductions of emissions of aerosol precursor gases from vehicles are essential to mediate pollution in China.     

大型工业企业污染物防治的会计成本控制策略研究

为了降低大型工业企业污染物防治的成本,提出会计成本控制策略研究。基于自然对数模型,对企业污染物防治的会计成本控制模型进行构建。采用最小二乘回归分析法,分析会计成本控制模型的约束变量,设计能源消费结构,将污染排放水平等参量作为结构的解释变量,对模型的回归系数进行计算,完成会计成本控制模型的构建。引入面板数据随机分析法,分析大型工业企业污染防治的弹性关系,通过会计成本控制模型,实现会计成本的最优控制。     

污染减排预警系统设计

随着经济的发展和人民生活水平的提高,污染物的排放量也越来越大,节能减排已经成为中国最重要的环保政策。要想实现节能减排,关键是实现从末端治理到污染预防的转变。本设计从源头控制的角度出发,结合中国社会经济的发展情况,运用预警理论和多种数学分析工具,研究建立了基于中国两大约束性指标SO2和COD的污染减排预警系统。该系统旨在对中国各省份的污染减排状况趋势进行预测和评估预警,最终通过一组类似于交通信号灯的标志发布预警信号,从而更加直观地反映出全国各省市的减排形势,为决策者提供形象、直观的理论依据。     

岩溶地下河系统中有机氯的分布特征与来源分析

选取重庆老龙洞、青木关岩溶地下河为研究对象,采用气相色谱仪-微池电子捕获检测器(GC-μECD)分析两条地下河水体中21种有机氯农药(OCPs)的浓度.结果表明,南山地下河中六六六(HCHs)和艾氏剂类化合物(ALDs)是主要检出物,青木关地下河中HCHs和甲氧滴滴涕是主要检出物.南山、青木关地下河中均未检出o,p'-DDE、p,p'-DDE、o,p'-DDD,同时,青木关地下河还未检出o,p'-DDT、狄氏剂,其余OCPs在两条地下河中检出率高达100%.青木关地下河中OCPs浓度范围为145~278 ng·L-1之间,平均值为213 ng·L-1;南山老龙洞地下河中OCPs浓度介于17.7~40.8 ng·L-1之间,平均值为32.7ng·L-1.两条地下河中各OCPs组分表现为地下河出口大于入口.通过对OCPs污染来源分析,发现两地下河流域滴滴涕(DDTs)主要来自于历史上工业DDTs输入,氯丹主要来自于大气沉降.六六六(HCHs)主要来源是林丹的输入,南山地下河属于历史污染,青木关地下河上游的甘家槽有新的HCHs输入.与国内外其他各水体相比,南山地下河水体中HCHs、DDTs浓度处于低水平;青木关下河处于中等偏高水平.结合中外用水卫生标准,发现南山地下河和青木关地下河未超过饮水安全标准.青木关应禁止农田施用有机氯农药,保护地下河生态环境.