A nanosilver-based spectrophotometric method for sensitive determination of methyl violet in river water

A method is reported for the determination of methyl violet in the range of 10–120 nmol L^?1. The method is based on the catalytic effect of silver nanoparticles (AgNPs) on the oxidation reaction of methyl violet by potassium bromate in acid medium. The reaction is followed spectrophotometrically by measuring the change in absorbance () at 620 nm using a fixed time method. The reaction variables were optimized in order to achieve highest sensitivity. The 3б criterion detection limit was 5 nmol L^?1, and the relative standard deviation for ten replicate determinations at a concentration of methyl violet of 15 nmol L^?1 was 0.97% (n = 10). The method was successfully applied to the determination of methyl violet in river water samples.     

温州市九山外河污染治理技术集成应用与治理成效

阐述了浙江省温州市九山外河污染治理技术的集成应用及治理成效。九山外河的综合整治工程采用了外源调水、底泥生态疏浚、河岸带阻控、人工曝气复氧和生态浮岛等多项技术,整治后的九山外河水体黑臭治理初见成效,水质由原来的劣Ⅴ类水逐步改善为Ⅴ类或Ⅳ类水,水体生境和生物多样性都有了一定的提高;将治理后对河流的实际感受与预期期望进行比较,69．2％的居民认为河流治理工程得分在60分以上,对河流治理总体比较满意。最后,对九山外河治理后管理存在的问题进行了分析并提出了建议与对策。     

北京北运河水系水质污染特征及污染来源分析

以北运河水系主要干支流2011年1～12月23项指标的监测数据为依据,采用水质类别法和平均综合污染指数法,对水质污染特征进行综合评价,运用主成分分析和系统聚类分析法,对水质指标主成分以及水质差异进行分类,并进一步对不同干支流污染来源进行分析.结果表明,北运河水系由于排污量大,地表水污染严重,除城市中心区部分河流水质为Ⅲ~Ⅳ类外,城市排水河流、远郊河流水质均为劣Ⅴ类.水质由3个主成分组成,COD、CODMn、BOD5、NH3-N、TP等为第一主成分;汞为第二主成分;石油类为第三主成分.干支流水质分为4类:第1类为清洁水源类河流,主要集中在城市中心区,降雨地表径流、雨污合流管网溢流引起的非点源污染是影响其水质达标的重要污染源;第2类为再生水水源类河流,主要集中在城市排水上游河流,城镇污水处理厂排水是其主要污染源;第3类为再生水与污水混合水源类河流,主要集中在城市排水下游河流及部分远郊区河流,由于城市下游排水管网不健全,远郊区污水集中处理率低,生活源和农业源的污染贡献率较高,水质污染严重;第4类为污水水源类河流,分布于远郊区县,农业污染占比较大,水质污染最严重.     

Concentrations of Hchs and Ddts in the Tissues of River Dolphins,Platanista Gangetica,From the River Ganges,India

Abstract

Concentrations of HCH and DDT organochlorine insecticide residues were measured in blubber, muscle and oil samples from three specimens of river dolphins, Platanista gangetica, from the River Ganges, India. Concentrations of HCH and DDT ranged from 94 to 289 ng g^?1 and from 1324 to 9388 ng g^?1 on wet wt. basis respectively. Comparisons are made with other aquatic mammals and other studies on river dolphins. P. gangetica appears to exhibit similar patterns of accumulation with age and with ß-HCH and p-p′-DDE being accumulated to higher levels than other HCH isomers and parent DDT and its other metabolites, respectively. These organochlorines may pose a health risk to river dolphin populations that are already showing evidence of environmental stress. Further studies are recommended.     

A case study of flood control schemes for the Kakehashi river and their socio-cultural consequences

SUMMARY

This paper is concerned with a twenty-five year campaign against the relocation of the Komatsu-Tenmangu shrine as a result of the enlargement of the Kakehashi river. The Komatsu-Tenmangu shrine is an important cultural property of Japan, and was constructed by Toshitsune Maeda, the third dynasty of the Kaga clan in 1657. It is suggested that the primary reason why it took so long to settle this issue is a flaw in our social system for managing public works. It is concluded that preservation of cultural property is not always contrary to land development, and that the proposed procedures or something like them must be put into practice for the real expansion of our culture.     

珠三角工业城市污染物入河量空间特征分析

以东莞市第一次全国污染源普查成果为数据基础,调查估算2010年东莞市33个镇街和25个水功能区的COD、氨氮入河量,并应用GIS技术及相关分析法分析污染物入河量空间分布特征及其影响因素。研究发现：①东莞市各镇街及水功能区的污染物入河量呈明显不均匀分布,人口、GDP是影响污染物入河量空间分布的主要因素。②河网区、非河网区镇街的工业污染物入河量与GDP均呈较好的正相关关系,但非河网区单位污染物入河量GDP产出拟合曲线斜率是河网区的31倍,显示河网区镇街每增长单位污染物入河量所产生的GDP远远小于非河网区,河网区镇街往往付出巨大的污染代价而经济增长却非常有限。     

长江三角洲城市内河环境治理的居民支付意愿比较研究 ——上海、南京与杭州实例调查

应用意愿价值评估法(CVM)的技术调查上海、南京和杭州城市内河环境治理的居民支付意愿,并探讨研究结果是否在城市间保持稳定.基于1258份问卷的统计分析,结果显示:上海、南京和杭州居民的支付意愿均值分别为20.5,25.4,20.3元/(户×月);进一步的线性对数模型分析结果表明,收入、环境意识等变量在3城市都呈现显著影响,而户籍、教育等因素在各城市模型中存在显著性差异;3城市混合数据模型显示,南京样本支付意愿显著高于其他2城市样本,杭州与上海调查样本无显著性差异.上述结果揭示了不同城市居民对城市内河治理的支付意愿呈现稳定性,为意愿价值评估法在我国不同区域间的“效益转移”研究提供了实证支持.但另一方面,参数模型表现出一定的差异,需要对模型作进一步的优化.     

Community structure and biotic integrity of aquatic plants along the North Canal in Beijing北大核心CSCD

Aquatic plants along the North Canal in Beijing were studied to identify the community structure of aquatic plants and vegetation index of biotic integrity (VIBI), and to provide scientific basis for the management and protection of urban rivers. Aquatic plants from 49 sampling sites along the North Canal were investigated during June 2015. Based on the field data, distributing range analysis, discriminatory power analysis, and correlation analysis were used stepwise to select core metrics from candidate metrics to establish the VIBI assessment system. The VIBI value of each sampling site was calculated as the average of the scaled values of all core metrics. Thirty-six aquatic plant species, including 14 hygrophytes, 13 emergent species, 6 submergent species, 2 floating-leaved species, and 1 floating species were collected. Species diversity was low in the North Canal, and no aquatic plants were recorded in 28 sampling sites, of which 9 sampling sites were dried up. Five sites were in excellent condition (VIBI > 0.60), 5 were good (0.60 > VIBI > 0.38), 7 were fair (0.38 > VIBI > 0.23), and 4 were poor (VIBI < 0.23). Based on the distribution of VIBI, Shahe River and Wenyu River upstream, and Fenghe River located in suburbs had a higher VIBI. Downstream tributaries, such as Qinghe River, Bahe River, and Liangshui River, had a lower VIBI. Correlation analysis showed that habitat quality, habitat complexity, and vegetation diversity along riparian zones were the important factors affecting VIBI along the North Canal, Beijing. Aquatic plants along the North Canal showed low species diversity owing to human disturbance. VIBI along tributaries with limited disturbance from human activities was higher; however, VIBI along tributaries disturbed by frequent human activities was lower. © 2018 Science Press. All rights reserved.     

Assessment of heavy metal pollution and health risks in a main river in Huayuan County,Xiangxi, Hunan Province北大核心CSCD

To study heavy metal pollution and assess the health risk of river water in Huayuan County, Xiangxi, Hunan Province, 11 water samples were collected from the Huayuan River and Brother Rivers in August and December 2016. Heavy metal (Pb, Zn, Cr, Cu, Fe, and Ni) concentrations were determined from the samples. The health risk assessment model recommended by the U.S. Environmental Protection Agency (USEPA) was applied to assess the health risk of heavy metals in the main surface waters of Huayuan County. The results indicated that the concentrations of heavy metals (Pb, Zn, Cr, Cu, Fe, and Ni) of surface water in the research area were 2.57 × 10-3, 4.66 × 10-4, 1.65 × 10-3, 6.27 × 10-4, 0.19, and 8.50 × 10-4 mg/L, respectively. The health risk of surface waters with heavy metals was high. Therefore, the chemical carcinogenic substance (Cr) health risk index was five or six times higher than that of chemical non-carcinogens (Pb, Zn, Cu, and Ni). The average health risk indices of non-carcinogenic substances were in the order Pb > Cu > Zn > Ni. The correlation and principal component analysis of surface water showed that the six heavy metal elements were composed of three main components in the main surface waters of the county. The first principal component was comprised of Fe and Ni (33.28%), which was mainly from internal pollution. The second component was comprised of Cu and Cr (26.98%), which was primarily due to industrial waste water, rainwater leaching mineral waste produced by heavy metal mining, and smelting enterprises. The third component, resulting from geochemical pollution, was Zn (17.10%). The health risk indices triggered by heavy metal in surface waters was high. Heavy metal pollutants in the research area need to be controlled in the order Cr, Pb, Cu, Zn and Ni. © 2018 Science Press. All rights reserved.