水源水库沉积物中稀土元素含量及赋存形态分析——以汤峪水库为例

利用ICP-MS和BCR连续提取法分别研究了西安蓝田汤峪水库沉积物中稀土元素含量和形态分布特征,并与中国土壤、渭南黄土和洛川黄土稀土元素含量进行了比较.结果表明:样品平均值均高于中国土壤和洛川黄土稀土元素含量,除La、Ce外,其它稀土元素均低于渭南黄土稀土元素含量;其中,Ce的含量分别是中国土壤、渭南黄土、洛川黄土的1.49、1.28和1.63倍.汤峪水库沉积物中稀土元素总量(∑REE)达211.41 mg·kg-1,∑LREE/∑HREE为9.99,均高于中国土壤、渭南黄土、洛川黄土;Ce的异常系数值为1.28,表明存在Ce的富集.由BCR连续提取法分析可知,Gd的酸可提取态(F1)比例高于其它形态,Gd由沉积物中向上覆水体迁移的可能性较强,产生的潜在环境效应也最明显.物源指示分析表明,汤峪水库沉积物中的稀土元素物质来源与洛川黄土相似.     

1株兼具好、厌氧汞甲基化能力细菌的分离鉴定

从三峡水库重庆段忠县石宝寨消落带土壤中,分离纯化后获得1株在好氧和厌氧条件下均能将Hg2+转化成甲基汞的细菌,经过对该菌株的形态特征、理化特征检测及16S r DNA序列分析,初步鉴定其为γ-变形菌纲的荧光假单胞菌,并命名为Pseudomonas fluorescens XD-Me Hg-B2(Gen Bank登录号:KU954349).通过汞敏感性试验发现该菌对Hg2+极敏感,汞甲基化试验表明,在初始Hg2+浓度为200 ng·L-1的PBS缓冲液中,接种XD-Me Hg-B2对数生长期菌悬液,有氧条件下,30℃孵育60 min后,溶液中甲基汞浓度呈指数增高,并在160 min时达到最大,约为3.85 ng·L-1±0.33 ng·L-1,最大汞甲基化率为1.93%;而在厌氧条件下,XD-Me Hg-B2同样表现出汞甲基化能力,但其甲基汞的生成较好氧处理显著滞后,且汞甲基化转化率较低,在180min左右甲基汞浓度达到最大,为2.86 ng·L-1±0.73 ng·L-1,最大汞甲基化率为1.43%.综上所述,P.fluorescens XDMe Hg-B2是1株对Hg2+极敏感,兼具好、厌氧汞甲基化能力的细菌,可望为消落带土壤汞生物甲基化的机制研究提供候选菌株,从而为深入研究汞生物地球化学循环、以及正确评价三峡水库蓄水运行后可能带来的汞生态风险评价提供理论依据.     

三峡库区潜在水环境风险源识别与分级评价方法研究

提出了区域潜在重大水环境风险源的识别方法,依据污染源所属行业性质、企业规模、污染危害程度、距离长江干流(或支流)的远近等判别因子,建立了区域潜在水环境风险源分级评价方法及其判别矩阵,对三峡库区的潜在水环境风险源进行了分级评价,评价结果表明Ⅰ级、Ⅱ级、Ⅲ级重大潜在风险源分别有30家、60家和98家,主要分布于长江干支流城区江段,空间分布不均衡,其中I级重大潜在水环境污染风险源主要分布于重庆的渝北区、长寿区和涪陵区。     

重庆三峡库区生态补偿标准差别化模型构建及应用研究

生态补偿是当前国际公认的重要的生态环境保护手段,但如何表征、量化和确定生态补偿标准,完善生态补偿机制,仍是当前生态补偿研究中的一个重要而未解决的问题.本研究以重庆三峡库区后续发展过程中不同本底类型的典型样区为研究对象,通过对重庆三峡库区各区域的自然和经济条件的分析,基于生态系统服务价值法和机会成本法,构建生态补偿标准化模型,引入差异系数,对重庆三峡库区各区域的生态补偿标准进行测算,科学制定各区域生态补偿分配标准.结果表明:位于库区西南段的主城区(包括渝北区、江北区、渝中区、江津区和北碚区等),这些区域经济实力雄厚,社会经济差异系数较大,但由于机会成本较低,受到自然价值和区域公平差异系数的影响较小,所以最终生态补偿额度比较低;三峡库区北段(巫山县、巫溪县、云阳县、奉节县和开县)的生态补偿额度较高,主要原因是机会成本大,受差异系数影响,理论损失成本大,但在这些地区的自然资源比较丰富,适合开展旅游行业,增加经济收入,缩小与其他区县的社会经济差距.     

饮用水水源保护区毗邻项目的环境管理研究

饮用水水源保护区是一种重要的生态红线类型,二级管控区内不得建设排放污染物的项目.毗邻生态红线的项目需得到重视,并进行严格的环境管理.以江苏句容备用水源地茅山水库旁某高端养老中心项目为例,研究其施工期、运营期对茅山水库饮用水水源保护区的污染影响,并针对性地提出若干环境保护建议与措施,为饮用水水源保护区毗邻项目施工、运营的环境管理提供参考,以保障饮用水安全.     

宜兴油车水库水质现状分析与保护对策研究

以宜兴油车水库饮用水源地为研究对象,采用单因子水质评价法对2012年－2014年的水质进行评价,评价结果显示油车水库水质达到《地表水环境质量标准》（ GB 3838－2002）中III类标准,并且对油车水库还做了富营养化评价,评价结果显示油车水库水质属于中营养,同时对比宜兴横山水库的水质状况,通过对水质监测、分析与评估,研究水质变化规律,为有针对性的保护饮用水源,进一步改善水质,优化水源管理提供科学依据,同时也相应的提出了一些适当的水源地保护建议。     

三峡库区典型农业小流域土壤溶解性有机质的紫外-可见及荧光特征

以三峡库区典型农业小流域土壤溶解性有机质(DOM)为研究对象,利用紫外-可见和荧光光谱,分析和讨论了不同土地利用类型(包括林地、田地、菜地和民用地)对土壤DOM地化特征的影响.结果表明,不同土地利用条件下DOM性质差异明显,以林地DOM的芳香性程度较高,腐殖化特征最强,其次为田地;尽管居民用地和菜地溶解性有机碳(DOC)含量高(均值分别为0.81 g·kg-1和0.89 g·kg-1),但是芳香化程度低,DOM中非生色组分对高DOC含量的贡献明显.所有样本荧光指数(FI)介于自生源特征(FI=1.9)和陆源特征(FI=1.4)之间,自生源(类蛋白组分)和异生源(类腐殖组分)对DOM均有贡献.大部分样本r(T/C)都大于2.0,说明该农业小流域土壤DOM受外来因素尤其是人类活动影响较大,尤以菜地为代表.另外,不同特征光谱参数对不同土地利用条件下DOM结构和性质差异性的灵敏程度不同,光谱斜率比值(SR)和腐殖化指数(HIX)不能反映DOM地化特征的差异性,因此单一光谱指标并不能全面提供DOM的特征信息,建议两种光谱分析方法联用.     

Bioinvasions in macrozoobenthos of the Volgograd Reservoir

On the basis of long-term monitoring of macrozoobenthos in the Volgograd Reservoir, the causes of changes in its species composition were analyzed and invading species were identified. During the first 20–25 years after construction of the reservoir, invading species appeared at a rate of 0.4 species per year. In the subsequent years, this rate increased to one species per year due to spontaneous expansion of species and the remote effect of their introduction.     

Impact on Mountainous Agricultural Development in the Three Gorges Reservoir Area forced by Migrants of the Three Gorges Project

The Three Gorges Project attracts worldwide attention because of the Three Gorges migrants, and the agriculture of the Three Gorges Reservoir Area is a foundation for the development of the Three Gorges migrants. The Three Gorges Reservoir Area is situated at the mountainous area with bad agricultural development conditions and relatively low levels of development. As a result, the large-scale migration fias special influence on its agricultural development, which has attracted much attention. The paper analyzes influence that the migrants have forced on its agricultural development based on the scientific data, and makes some explorations on the models that are suitable for the development of mountainous agriculture in the Three Gorges Reservoir Area.     

Radiological and multi-element analysis of sediments from the Proserpina reservoir (Spain) dating from Roman times

The Proserpina dam was built in Roman times to provide drinking water to Emerita Augusta (today's Mérida in SW Spain). During maintenance work, a sediment core was extracted, offering an excellent opportunity to analyze the historical environmental impacts of the dam and its reservoir over the 2000 years since Roman times. In order to establish an accurate chronology, ¹⁴C ages were determined by accelerator mass spectrometry (AMS). Core samples were assayed for their content in uranium and thorium series isotopes, ⁴⁰K, and the anthropogenic radionuclides ¹³⁷Cs, ⁹⁰Sr, and ^239+240Pu. Potassium-40 presented the highest activity level and was not constant with depth. The uranium and thorium series were generally in equilibrium, suggesting there had been no additional input of natural radionuclides. The presence of ¹³⁷Cs was only found in relation with the global fallout in the early 1960s. Multi-element assays were performed using the PIXE and PIGE techniques. Some variations in the multi-element concentrations were observed with depth, but the sediment core could be considered as clean, and no presumptive anthropogenic pollutants were found. Nevertheless, an unusually high Zn content was detected at depths corresponding to pre-Roman times, due to geological anomalies in the area.