Persistent organochlorine residues in sediments of the Haihe River and Dagu Drainage River in Tianjin, China

Persistent organochlorine compounds were analyzed by means of GC-ECD in surface sediment samples from two selected rivers in Tianjin, Haihe River and Dagu Drainage River. A total of 16 surface sediment sites were selected along the both rivers. The frequency of detection of T-HCH and T-DDT in sediment samples both was up to 100%, which illustrated that the contamination of HCH and DDT was widespread in Haihe and Dagu Drainage Rivers. Results indicated that the concentrations of various pesticides in sediments from Haihe River were in the range of 3.30-75.96 ng/g dw for T-HCH and 1.57-211.57 ng/g dw for T-DDT. Compared with Haihe River, Dagu Drainage River was contaminated by HCHs and DDTs along the all locations and the values of T-HCH and T-DDT residues in sediments ranged from 2.30 to 124.61 ng/g dw and from 11.28 to 237.30 ng/g dw, respectively, The possible pollution sources were analyzed through monitoring results of organochlorine pesticides（OCPs） residues in sediments from the two rivers. The investigation also indicated that HCH was still used as pesticide in Tianjin partial area.     

长江三角洲晚第四纪陆-海交互地层的光释光年代学

长江三角洲地层的年代学研究对探讨晚第四纪以来我国东部沿海地区陆海交互作用历史以及海岸地貌的形成与演化具有重要价值。本研究选择长江三角洲YZ07和EGQD14两支钻孔开展系统光释光（optically stimulated luminescence,OSL）测年研究,总结前期已发表的50个年代数据并收集整理该区域相关钻孔的年代地层资料,探讨在可靠的年代框架约束下晚第四纪长江三角洲沉积地层演变特征,取得了以下几点认识：（1）在长江三角洲地区,常规OSL测年以较细石英颗粒OSL测年效果较为理想;对粗颗粒石英,若存在长石包裹体对石英OSL信号的影响,建议用脉冲释光测年（POSL）技术加以解决。（2）以YZ07孔为例,¹⁴C测年和OSL测年结果对比表明在三角洲海岸地区,¹⁴C测年方法建立的年代地层框架需要谨慎对待,建议在此区域开展年代地层学研究时可以尝试将两种测年方法结合使用,以确保年代地层框架的准确和可靠。（3）针对争议较大的氧同位素3阶段（MIS3）沉积环境问题,EGQD14孔给出了新的年代学证据,认为MIS3阶段（约30?—?50 ka）长江三角洲可能是陆地河流相沉积环境为主导,这也得到了区域相邻的几支钻孔沉积记录的佐证。（4）两支钻孔从年代学角度证实了前人关于末次盛冰期（Last Glacial Maximum,LGM）以来长江三角洲发育下切河谷的沉积学判识和地层学论断。此外,多钻孔的年代地层学特征也验证了全新世时段海平面变化控制下的长江三角洲及海岸演变的时空动态。     

季节性Kendall检验分析湘江长沙段水质变化趋势

季节性Kendall检验是一种广泛应用于河流水质变化趋势分析的非参数检验。以湘江长沙段三汊矶断面2001—2011年水质监测结果为样本,运用季节性Kendall检验分析湘江长沙段水质变化趋势及影响因素,结果表明:氨氮浓度呈显著上升趋势,总磷浓度呈高度显著上升趋势,总镉、总砷浓度呈高度显著下降趋势,湘江长沙段水质主要受城市生活、工业和农业面源污染物排放的影响,河水流量对水质的影响相对较小。     

Heavy metal adsorption on the Le An River sediment —The adsorption model

In this study,the surface properties and adsorption properties of the Le An River sediment were modelled via surface complexation approach.The model parameters were determined based on the data of our potentiometric titration experiments and the metal adsorption experiments with the Le An River sediment samples.Consequently,the surface complexation models for the natural sediment,in our case the Le An River sediments,which can interpret the experimental data very well were successfully established.Three typical surface complexation models that is the constant capacitance model,the diffuse layer model and the triple layer model,were considered in this research.This work indicated that the consistency and the interdependency among model parameters together with the selection of the surface adsorbed species should be emphasized.     

Hydromorphological and socio-cultural assessment of urban rivers to promote nature-based solutions in Jarabacoa,Dominican Republic

In Latin America and the Caribbean, river restoration projects are increasing, but many lack strategic planning and monitoring. We tested the applicability of a rapid visual social–ecological stream assessment method for restoration planning, complemented by a citizen survey on perceptions and uses of blue and green infrastructure. We applied the method at three urban streams in Jarabacoa (Dominican Republic) to identify and prioritize preferred areas for nature-based solutions. The method provides spatially explicit information for strategic river restoration planning, and its efficiency makes it suitable for use in data-poor contexts. It identifies well-preserved, moderately altered, and critically impaired areas regarding their hydromorphological and socio-cultural conditions, as well as demands on green and blue infrastructure. The transferability of the method can be improved by defining reference states for assessing the hydromorphology of tropical rivers, refining socio-cultural parameters to better address river services and widespread urban challenges, and balancing trade-offs between ecological and social restoration goals.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01565-3.     

宜昌市沮漳河流域当阳段水环境现状调查与评价

对宜昌市沮漳河流域当阳段的水环境进行了调查和评价。通过区域自然环境、社会经济发展、水体功能区、水环境容量等分析以及多个断面数据的监测,表明沮漳河流域当阳段水环境质量不能满足Ⅲ类水体功能区要求,主要超标因子为高锰酸盐指数、NHrN、BOD5、TP、石油类,主要受沿岸工业废水、生活污水及农业面源污染所致。     

Dams in the Amazon: Belo Monte and Brazil’s Hydroelectric Development of the Xingu River Basin

Hydroelectric dams represent major investments and major sources of environmental and social impacts. Powerful forces surround the decision-making process on public investments in the various options for the generation and conservation of electricity. Brazil’s proposed Belo Monte Dam (formerly Kararaô) and its upstream counterpart, the Altamira Dam (better known by its former name of Babaquara) are at the center of controversies on the decision-making process for major infrastructure projects in Amazonia. The Belo Monte Dam by itself would have a small reservoir area (440 km²) and large installed capacity (11, 181.3 MW), but the Altamira/Babaquara Dam that would regulate the flow of the Xingu River (thereby increasing power generation at Belo Monte) would flood a vast area (6140 km²). The great impact of dams provides a powerful reason for Brazil to reassess its current policies that allocate large amounts of energy in the country’s national grid to subsidized aluminum smelting for export. The case of Belo Monte and the five additional dams planned upstream (including the Altamira/Babaquara Dam) indicate the need for Brazil to reform its environmental assessment and licensing system to include the impacts of multiple interdependent projects.     

Assessing the Effects of Alternative Setback Channel Constraint Scenarios Employing a River Meander Migration Model

River channel migration and cutoff events within large river riparian corridors create heterogeneous and biologically diverse landscapes. However, channel stabilization (riprap and levees) impede the formation and maintenance of riparian areas. These impacts can be mitigated by setting channel constraints away from the channel. Using a meander migration model to measure land affected, we examined the relationship between setback distance and riparian and off-channel aquatic habitat formation on a 28-km reach of the Sacramento River, California, USA. We simulated 100 years of channel migration and cutoff events using 11 setback scenarios: 1 with existing riprap and 10 assuming setback constraints from about 0.5 to 4 bankfull channel widths (bankfull width: 235 m) from the channel. The percentage of land reworked by the river in 100 years relative to current (riprap) conditions ranged from 172% for the 100-m constraint setback scenario to 790% for the 800-m scenario. Three basic patterns occur as the setback distance increases due to different migration and cutoff dynamics: complete restriction of cutoffs, partial restriction of cutoffs, and no restriction of cutoffs. Complete cutoff restriction occurred at distances less than about one bankfull channel width (235 m), and no cutoff restriction occurred at distances greater than about three bankfull widths (∼700 m). Managing for point bars alone allows the setbacks to be narrower than managing for cutoffs and aquatic habitat. Results suggest that site-specific “restriction of cutoff” thresholds can be identified to optimize habitat benefits versus cost of acquired land along rivers affected by migration processes.     

金沙江上游赠曲的鱼类与裸腹叶须鱼的食性

2013年5月和9月对金沙江上游支流赠曲的鱼类资源和裸腹叶须鱼的食性特征进行了调查研究。结果表明,赠曲现有鱼类10种,隶属2目3科5属,其中鲤科鱼类7种,占70%;鮡科2种,占20%;鳅科1种,占10%。赠曲裸腹叶须鱼的食物组成包括53种(属)的浮游藻类、原生动物和节肢动物等。硅藻门是出现率百分比、相对重要性指数和数量百分比最高的饵料生物;水生昆虫是质量百分比最大的饵料生物。裸腹叶须鱼的摄食强度存在较明显的季节差异,雨季末期的摄食强度较低。食物中植物性饵料相对重要性随着裸腹叶须鱼体长的增长而增加。综合而言,赠曲的鱼类组成较为简单,鲤科鱼类是优势类群;裸腹叶须鱼属杂食性鱼类,且摄食强度存在季节性差异。为保护赠曲鱼类,建议在赠曲梯级水力开发过程中做好鱼类栖息地保护或再造等生态补偿措施。     

长江中游城市群经济与生态成本空间演化模式分析

综合运用变异系数、泰尔指数及ESDA-GIS多种方法,在充分考虑传统经济影响因子的基础上,尝试引入经济发展生态成本指标,分析长江中游城市群经济综合发展水平与生态成本的空间匹配及演化模式。研究表明:经济综合发展水平高低聚集特征明显,空间极化现象是导致区域经济发展不平衡的主要原因;生态成本空间集聚现象以高高集聚和低低集聚为主,且呈现出高高集聚减少、低低集聚增多的现象,生态成本消耗有所改善;2001~2012年长江中游城市群市域经济综合发展水平与生态成本表现出越来越显著的差异化空间格局,呈现出由低经济综合发展水平-低生态成本过渡到高经济综合发展水平-高生态成本,进而发展到高经济综合发展水平-低生态成本的空间匹配模式的阶段性特征;高经济综合发展水平-高生态成本的经济发展模式仍在大部分城市中存在,经济与生态空间协调发展的潜力仍然很大。