Dynamic risk assessment of oil spill scenario for Three Gorges Reservoir in China based on numerical simulation

A novel method for dynamic risk assessment of oil spill accidents based on numerical simulation was presented in this paper. The dynamic risk assessment model was developed consisting of a comprehensive list of caused consequences like environmental damage, asset loss, health impact and social effect as well as emergency actions preventing these losses. Contributing events in the Mater Logic Diagram (MLD) of the dynamic risk assessment model were valued based on the simulated evolvement of oil contaminants under spill scenario on quasi-static fluid, which was obtained by coupling an oil spill model with hydrodynamic module in Jialing river of Three Gorges Reservoir in China after the impoundment of the reservoir to 175 m water level in 2010. Calculated result of dynamic risk as grade IV indicated that the assessed oil spill was not as catastrophic as we thought because of the slow transport of oil fractions on water surface and absence of dispersed oil in water body due to the quasi-static fluid, very gentle wind and effective emergency actions, as well as by the reason that rare agriculture or industrial crops exist in spill adjacent area.     

三峡库区湿地生态建设与保护利用

三峡工程的兴建给库周地区带来了前所未有的发展机遇,但同时也给库区的生态环境建设带来了新的问题。水库蓄水将导致库区的人地矛盾更加突出,环 境容量不足等等。三峡水库周边的水位变动区域的干、湿交替区——湿地系统,具有独特的结构、功能和环境景观特点,新建大型水库周边湿地开发利用对库区移民安置及经济发展意义重大,应对其进行有效、合理、安全的综合开发利用。三峡库区湿地的水位具有年内周期性涨落变化特点,以库区水位变动带来划分不同的区域,并结合库区涨落带的坡度、土壤和水文等条件,探索与不同湿地区域段相适宜的保护和开发利用方式。这种因地制宜的湿地生境开发利用途径对缓解库区人地矛盾,改善库区生态环境和景观将发挥积极作用。     

重庆缙云山典型林分林地土壤抗蚀性分析

对三峡库区重庆缙云山4种典型林分(针阔叶混交林,常绿阔叶林,楠竹林和灌木林)林地土壤的抗蚀性指标进行主成分分析,并以农地土壤作对照,研究表明,可将衡量土壤抗蚀性的13个指标压缩为7个最佳指标。用抗蚀性指标主成分分析综合指数表明4种林分林地土壤抗蚀性为：灌木林(45.51)>混交林(41.94)>阔叶林(32.65)>楠竹林(23.35);重庆缙云山土壤从表层到底层抗蚀性能呈下降趋势（49.32,41.86,32.03,27.11）。通过模糊聚类分析可将重庆缙云山不同土地利用类型不同层次的19个土壤样本划分为抗蚀性强度不同的3类。     

长江三峡水库水污染控制若干问题

论述了三峡水库几个重要水环境问题,对近年来三峡水库水污染控制科学研究工作进行回顾,评述了一些重要研究成果,就三峡水库水质模拟、水体富营养化、水库泥沙截留淤积和重金属污染等问题进行了深入探讨。基于国际水协会最新推出的河流水质模型,提出了三峡水库水环境模拟研究的观点和方法;基于湖泊（水库）生态动力学模型原理,在对水体中磷元素预测的基础上,从营养盐含量、水深、流速、温度因素等与富营养化非线性映射关系出发,初步建立三峡水库水体富营养化人工神经网络模型,对三峡水库水体富营养化潜势进行研究,分析讨论了一些初步结果;论述了水库泥沙截留淤积及其与水体中污染物,特别是重金属污染的相互作用;建议三峡水库近期内应予以重视的一些重要水环境科学问题。     

北京官厅水库水体中挥发性有机物健康风险评价

为研究北京官厅水库水体中挥发性有机物对人体产生的潜在健康危害风险,从9个有代表性的采样点采集水样,用顶空气相色谱法测定了挥发性氯代烃的质量浓度,所检测的5种挥发性氯代烃的质量浓度总量为5.33～97.74 ng/L,同时讨论了其污染水平和分布特点.应用美国环境保护署(US EPA)的健康风险评价方法,对官厅水库水体中挥发性氯代烃通过食入和皮肤接触2种途径进入人体的危害进行了风险计算和初步评价. 结果表明:水库中各采样点的非致癌风险和致癌风险均未超标,从位于桑干河八号桥的6号采样点采集的水样中挥发性氯代烃的非致癌风险值达到10－4数量级,其余采样点的非致癌风险值均在10-5数量级;各采样点的致癌风险指数远远低于10－4的数量水平. 因此,初步认为目前官厅水库水体中挥发性氯代烃不会对人体产生明显的健康危害.      

A physical-microbial food web coupled model to study the evolution of the ecological functioning of a new reservoir after its flooding (Sep,Puy de Dôme)

The aim of this paper is to understand the temporal changes in planktonic populations and to highlight some important factors that control the biological functioning and evolution of a recently flooded reservoir, the Sep reservoir (Massif Central, France). To achieve this objective, a 1D vertical coupled physical–biological model was used and developed. It couples relevant physical processes (dispersion, advection and convection) with biological processes taking into account the complexity of interactions within the microbial food web, including the conventional grazing food chain with a microbial loop.     

Field test of best management practice pollutant removal efficiencies in Shenzhen, China

This paper presents a study on the use of best management practices (BMPs) for controlling nonpoint pollution in the Xikeng Reservoir watershed located in Shenzhen, China. A BMP treatment train design, including a pond, a wetland, and a buffer strip placed in series was implemented at the reservoir location. A separate grass swale was also constructed at the site. Low impact development (LID) BMPs, namely a planter box and bioboxes, were used at the parking lot of the reservoir’s Administration Building. Samples were collected during storm events and were analyzed for total suspended solids (TSS), biochemical oxygen demand (BOD₅), ammonia nitrogen (NH₃—N), and total phosphorus (TP). The removal efficiencies of both BMP systems were evaluated using the Efficiency Ratio (ER) method based on the event mean concentration (EMC) data. In summary, the pond/wetland treatment train removed 70%―90% of TSS, 20%―50% of BOD₅, and 30%―70% of TP and NH₃—N. The swale removed 50%―90% of TSS, 30%―55% of BOD₅, −10%―35% of NH₃—N, and 25%―70% of TP. For the planter box and biobox, the ranges of removal rates were 70%―90%, 20%―50%, and 30%―70% for TSS, BOD₅, and ammonia and phosphorus, respectively.     

三峡大宁河水体光学特征及其对藻类生物量的影响

基于2012-04-27—2013-01-19大宁河不同水文期的监测数据,确定大宁河水体光学特性的季节变化特征,并探究其对藻类生物量的影响. 结果表明:①不同水文期大宁河的D_eu(真光层深度)差异显著(P＜0.01),最高值出现在高水位运行期,为(5.22±2.70)～(8.71±5.20)m;最低值出现在汛限期,为(3.22±0.08)～(3.81±0.14)m. ②回归分析结果表明,ρ(SS)能较好地反演真光层深度的时空变化规律,而ρ(Chla)的解释度不高,仅用ρ(SS)即可有效地反推真光层深度. ③利用局部多项式回归拟合大宁河E_t(总能量密度)和浮游生物量的回归模型,结果表明,在100t≤300时,藻类生物量随着E_t的增加而增大;E_t>300时则出现“光抑制”现象,藻类生物量随着E_t的增加而减少,基本符合藻类生物量随光辐射强度而改变的响应机制.      

三峡库区消落带草本植物碳氮磷释放及影响因素

以三峡库区消落带优势草本植物狗牙根(Cynodon dactylon)、牛鞭草(Hemarthriaaltissima)、稗草(Echinochloacrusgalli)、狗尾草(Setariaviridis)和马唐(Digitariasanguinalis)为试验植物,在室内进行了为期60 d的淹水模拟试验,并对消落带优势草本植物淹水后TOC、TN和TP的释放特征及影响因素进行了研究. 结果表明:5种优势草本植物淹水后均可导致水中pH降低,TOC、TN和TP的U_max(最大单位累积释放量)分别为21.03~43.65、0.50~3.23和0.54~2.69 mg/g,U_max出现在淹水第15~20天,并且TOC、TN和TP的R(释放速率)差异显著;水体中微生物、水体温度和上覆水中ρ(TOC)、ρ(TN)、ρ(TP)对植物淹水后TOC、TN和TP的释放均有一定影响. 在对消落带植被调查研究的基础上,根据淹水试验植物的U_max,对蓄水后三峡库区消落带植被TOC、TN、TP的释放量进行了估算,在蓄水后20 d内,消落带植被可向水体释放大量的TOC、TN和TP,蓄水初期可能会引起库区局部水域水质恶化,影响水库的水环境安全.      

基于GWLF模型的于桥水库入库河流水文模拟及氮磷负荷估算

流域模型技术应用是当前开展面源污染防治的重要工具,而水文过程的准确模拟是进行污染负荷估算的首要环节和关键步骤。为了弄清近年来于桥水库入库河流氮、磷输入负荷,选取GWLF模型对水平口子流域的水文过程进行模拟,首先利用2006—2018年气象、水文资料率定模型水文参数,然后将参数推广到整个流域,对2019—2020年3条主要入库河流流量进行模拟,最后乘以相应河流断面的总氮、总磷浓度估算氮磷输入负荷。结果显示：GWLF模型适用于研究区的水文过程模拟,校准期和验证期的纳氏系数分别为0.89和0.91,平均相对误差分别为12.2%和13.1%;2020年总氮入库负荷为3 977.0 t,其中引滦调水贡献占57.0%,3条入库河流共贡献43.0%;总磷入库负荷为48.8 t,其中引滦调水贡献占68.6%,3条入库河流共贡献31.4%。GWLF模型输入数据需求量较少,模型参数较少,模拟效果较好,适用于中小型流域的水资源和水环境管理,具有一定的推广应用前景。