Upstream Sediment‐Control Dams: Five Decades of Experience in the Rapidly Eroding Dahan River Basin,Taiwan

Sedimentation is emerging as a key issue in sustainable reservoir management. One approach to controlling reservoir sedimentation is to trap sediment in hydraulic structures upstream of the reservoir. In the 1,163‐km² catchment of the Dahan River (Taiwan) over 120 “sabo” dams were built to reduce sediment yield to Shihmen Reservoir. Built in 1963 for water supply, Shihmen has lost over 40% of its 290‐Mm³ storage capacity to sedimentation. Most of these upstream structures were small, but three had capacities >9 Mm³. Field measurements and historical data from the Water Resources Agency show most smaller dams had filled with sediment by 1976. The three largest were full or nearly so by 2007, when one (Barlin Dam) failed, releasing a pulse of 7.5 Mm³, most of its 10.4 Mm³ stored sediment downstream. The Central Range of Taiwan is rapidly eroding (denudation rates 3‐6 mm/yr), so geologically high loads make sediment problems manifest sooner. Even in other environments, however, eventually small dams built upstream of large reservoirs are likely to fill themselves, creating multiple small sediment‐filled reservoirs, some located in sites inaccessible to mechanical removal. Our analysis suggests sabo dams do not offer a long‐term basis for controlling reservoir sedimentation in such a high‐sediment yield environment. Sustainable solutions must somehow pass sediment downstream, as would be accomplished by a sediment bypass around Shihmen Reservoir, as now being studied.     

石墨炉原子吸收法测定水中铅的质量控制指标研究

通过对全国9个省份82家实验室监测数据的分析,研究确定了石墨炉原子吸收法测定水中铅的质量控制指标。建议控制值为：标准样品室内相对标准偏差（RSD）≤5.0%,实际样品相对偏差（RD）≤30.0%,标准样品室间相对标准偏差（RSD’）≤10%,标准样品相对误差（RE）≤±8.0%,加标回收率范围为90%～115%,同时还对方法的重复性和再现性指标进行了验证性研究。     

Characterizing wetland change at landscape scale in Jiangsu Province, China

Human activities produced great impacts on wetlands worldwide. Taking Jiangsu Province, China, as a representative wetland region subject to extensive human activities, the aim of this study is to understand the conversion trajectory and spatial differentiation in wetland change from a multi-scale perspective. Based on multi-temporal Landsat images, it was found that the natural wetlands decreased by 11.2% from 1990 to 2006 in Jiangsu Province. Transition matrices showed that the conversion of natural wetlands to human-made wetlands (mostly aquaculture ponds) was the major form of natural wetland reduction, accounting for over 60% of the reduction. Percentage reduction and area reduc tion of natural wetlands were respectively quantified within different wetland cover zones using a moving window analysis. Average percentage reduction showed a decreasing tendency with increasing wetland cover. The high-cover and mid-cover zone presented the largest area reduction at the scales of 1-2 km and 4-8 km, respectively. Local hotspots of natural wetland reduction were mapped using the equal-interval and quantile classification schemes. The hotspots were mostly concentrated in the Lixiahe marshes and the coastal wetland areas. For the area reduction hotspots, the quantile classification presented larger area and more patches than the equal-interval classification; while an opposite result was shown for the percentage reduction hotspots. With respect to the discontinuous distribution of the natural wetlands, area reduction could be more appropriate to represent reduction hotspots than percentage reduction in the study area. These findings could have useful implications to wetland conservation.     

Enantioselective ecotoxicity of the herbicide dichlorprop and complexes formed with chitosan in two fresh water green algae

To reduce the leaching potential, to prevent groundwater contamination and to maintain the efficacy of a pesticide, natural polysaccharides have received increasing attention due to their biocompatibility and useful biological reactivity for controlled release formulations (CRFs) of pesticides. In this paper, the toxicities of the chiral herbicide dichlorprop (DCPP) and its complexes with chitosan molecules (DCPP-CS) and chitosan nanoparticles (DCPP-NP) to two different green algae were determined and compared. The inhibition rates of DCPP, DCPP-CS and DCPP-NP were determined at 24, 48, 72, 96, 120, 144, 168 h, and the results show that (S)-DCPP was more toxic to Chlorella vulgaris than (R)-DCPP, while the (R)-DCPP was more toxic to Scenedesmus obliquus than (S)-DCPP. The study also found that the chiral selectivity of DCPP to Chlorella vulgaris and Scenedesmus obliquus could be changed when DCPP was complexed with chitosan molecules (CS) or chitosan nanoparticles (NP). For Chlorella vulgaris, the order of inhibition was (R)-DCPP-CS > (S)-DCPP-CS and (R)-DCPP-NP > (S)-DCPP-NP; for Scenedesmus obliquus, the order was (S)-DCPP-CS > (R)-DCPP-CS and (S)-DCPP-NP > (R)-DCPP-NP. This phenomenon suggests that the enantioselective behaviors of chiral compounds might shift when interactions with other chiral receptors coexist in different biological environments. Additionally, chitosan molecules and chitosan nanoparticles also showed different toxicities, which could be ascribed to the difference in the physicochemical properties between CS and NP or the differences in the cell walls of the two fresh water green algae.     

Mercury consumption and contamination of environment in gold mining in China

1　ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｇｏｌｄｉｎｄｕｓｔｒｙｉｎＣｈｉｎａｇｒｏｗｓｕｐｑｕｉｃｋｌｙｗｉｔｈｔｈｅｇｒｏｗｔｈｒａｔｅｏｆａｂｏｕｔ 10 %ｓｉｎｃｅ 90’ｓ.Ｉｎ 1995,ｔｈｅｐｒｏｄｕｃｔｉｏｎｏｆｇｏｌｄｗａｓｏｖｅｒ10 0ｔｏｎｓ/ａ,ａｎｄｉｎ 1996ｒｅａｃｈｅｄ 12 0ｔｏｎｓ/ａ .Ｉｔｉｓｒａｎｋｅｄｓｉｘｔｈｉｎｔｈｅｗｏｒｌｄ(Ｃｈａｎｇ ,1995) .Ｔｈｅｉｒｍａｉｎｐｒｏｃｅｄｕｒｅｓｏｆｇｏｌｄｅｘｔｒａｃｔｉｏｎａｒｅ :(1)ｃｙａｎｉｚａｔｉｏｎｉｎｔｏｔａｌｏｒｅ ｃａｒｂｏ…     

植物遗传资源保护与利用的市场化机制和国际制度

随着植物物种资源的不断减少和因生物技术迅猛发展对植物遗传资源需求的不断增加 ,植物遗传资源正逐步由公共物品转变为稀缺物品。坚持《生物多样性公约》所确立的遗传资源效益公平分享原则 ,完善现有国际多边体系 ,促进以“遗传编码功能”价值概念和遗传资源保护效应“内部化”与“补偿”方案为基础的植物遗传资源市场化保护与利用机制的形成 ,建立“植物遗传资源交易所”和“生物多样性合作社” ,将有助于提高世界各国尤其是发展中国家保护植物遗传资源的积极性 ,实现全球植物遗传资源的可持续利用     

大城市污水处理工艺的经济选择因素

城市污水处理设施的建设是今后改善我国城市环境的重要任务之一，其具体工艺和技术的选择除了对污水治理的结果产生影响外，更重要的是直接影响对设施建设的投入强度和运行效果，建议从经济和技术结合的角度研究比较各种技术和工艺，去探讨经济技术最佳结合的方法。     

Fe(Ⅱ)EDTA络合吸收-铁粉还原再生脱除NO性能

利用Fe(Ⅱ)EDTA络合吸收-铁粉间歇还原再生脱除NO并回收氨资源的方法,实验研究了铁粉还原再生Fe(Ⅱ)(NO)EDTA的过程及其影响因素。结果表明,以0.015 mol/L的Fe(Ⅱ)EDTA做吸收剂,在起始pH 5.5、温度323K条件下吸收400×10-6~500×10-6的NO,脱除率95%以上;铁粉还原再生Fe(Ⅱ)(NO)EDTA过程可用缩芯模型阐释;铁粉添加量与搅拌强度直接决定了铁粉质点数量,是影响反应的重要因素;实验中Fe(Ⅱ)(NO)EDTA络合液150 mL,氧气含量为5%时,搅拌速度900 r/min、粒径为0.12 mm的铁粉浓度5.3 g/L、温度353 K、pH=6为最适宜再生条件。     

四川盆地土壤微量元素生态类型研究

本研究从生态学观点出发,根据土壤缺乏微量元素的临界值指标,探究了四川盆地土壤微量元素的生态类型,按其土壤供给有效态微量元素的丰缺程度,将本区土壤微量元素分为五种生态类型:严重缺乏、缺乏、适中、丰富和很丰富。统计结果表明,四川盆地各类土壤的微量元素生态类型特点为:有效硼含量很低,普遍严重缺硼;有效锌含量亦低,近半数土壤缺锌;多数土壤有效锰含量丰富,仅少部分土壤供锰不足;有效铜和铁的含量丰富。     

Immobilization and transformation of co-existing arsenic and antimony in highly contaminated sediment by nano zero-valent iron

Arsenic(As) and antimony(Sb) are usually coexistent in mine wastes and pose a great threat to human health. The As immobilization by nano zero-valent iron(n ZVI) is promising, however, the stabilization for co-occurring As and Sb is not known. Herein, the immobilization and transformation of As and Sb in n ZVI-treated sediments were evaluated using complementary leaching experiments and characterization techniques. Raw sediment samples from a gold-antimony deposit revealed the co-existence of ul...