Population structure and community characteristics of Acer catalpifolium Rehd北大核心CSCD

Acer catalpifolium Rehd., a critically endangered tree species with an extremely limited range of distribution, is one of the 120 plant species with extremely small populations, as approved by the state forestry administration of the People's Republic of China and requires urgent rescue action. In order to comprehensively understand the population status and the future developmental trend of A. catalpifolium, the plant communities were investigated from 5 sites, including Caishenmiao (CSM), Banruosi (BRS), Zhangshancun (ZSC), Fuhusi (FHS), and Baoguosi (BGS). The population structure of A. catalpifolium as well as the species composition and community characteristics of its habitat were investigated. The results showed that A. catalpifolium is mainly distributed in the evergreen broad-leaved and deciduous broad-leaved mixed forests, in different community layers, namely, the tree layer, shrub layer, and herb layer, and is accompanied by 52, 74, and 52 plant species, respectively. Analyses of the distribution of population abundance revealed that BRS had the largest distribution of A. catalpifolium, accounting for 26.04% of the total population, followed by FHS, ZSC, BGS, and CSM, in that order. Analyses of the community characteristics revealed that the species diversity indices in FHS, BRS, BGS, and CSM were greater than that in ZSC. Analyses of the population age structure of A. catalpifolium revealed the gap in the distribution of the levels of seedlings and young trees. There were serious obstacles to the regeneration of the natural population. We concluded that the obstacle to the regeneration of the population of A. catalpifolium might be caused by the high competitive pressure from the dominant species and the micro-environment in the forest. Understanding the community characteristics and the population structure of A. catalpifolium could provide a theoretical foundation for its reintroduction and recovery. © 2018 Science Press. All rights reserved.     

Effects of water velocity on bulk water quality and biofilm population structure in drinking water distribution systems北大核心CSCD

To study the effect of flow velocity on drinking water distribution systems, bulk water quality was monitored over 28 days, biomass was measured, and 16S rDNA was sequenced on the 28th day using a water distribution simulation system. The relationship between bulk water quality and biofilm was statistically analyzed. Flow velocity of 0.5 m/s yielded the most total organic carbon (TOC) (5.26 ± 0.17 mg/L) in the bulk water, the most bulk water bacteria (lg (n+1/mL-1) = 4.79 ± 0.02), the worst bulk water quality, and the most biofilm bacteria (lg (n+1/cm-2) = 5.48 ± 0.06). A Pearson correlation analysis showed the total number of biofilm bacteria was positively correlated with conductivity (R = 0.73, P < 0.01), turbidity (R = 0.87, P < 0.001), TOC (R = 0.94, P < 0.001), and total bacteria (R = 0.92, P < 0.001), and was negatively correlated with residual chlorine (R = -0.68, P < 0.05). Biofilm diversity was high under the low (0.1 m/s) and high (2.5 m/s) flow rates, but the bacterial diversity of biofilm was the lowest at the 0.5 m/s flow rate, in which Proteobacteria dominated the biofilm community structure. These results suggest that flow velocity affects bulk water quality and biofilm population structure, and water quality and biofilm population structure are interrelated, which provides the theoretical basis for research on biofilms in drinking water distribution systems. © 2018 Science Press. All rights reserved.     

广东省“十二五”生态环境时空变化趋势及影响因素

基于2011—2015年Landsat7、Landsat8等卫星遥感影像,结合土壤侵蚀面积、水资源量、降雨量、污染物排放量等统计数据,按照《生态环境状况评价技术规范》(HJ 192—2015),研究评价广东省"十二五"期间生态环境状况及其时空变化趋势,并对其影响因素进行综合分析。结果表明,广东省的生态环境状况总体为优,各市生态环境状况均属优、良,粤北生态环境状况整体最好;广东省及各市生态环境状况稳中趋好,但呈现温和地波动变化;主要污染物排放量下降和水资源总量提高是促进生态环境状况改善的主要原因。     

松花江流域大型底栖动物生物完整性指数构建及其适用性

利用生物完整性指数评价河流健康状态,对于水环境管理决策具有重要的实践意义。基于大型底栖动物构建生物完整性指数(B-IBI),并评价松花江流域的水生态系统健康状况。在松花江主要干支流设定37个采样点,分别于2016年6、9月进行环境因子和大型底栖动物调查研究。最终从28个候选参数中确定了种类总数、摇蚊种类数、敏感种百分比、Hilsenhoff指数、Marglef指数作为核心参数构建B-IBI。通过0～10赋分法,计算得到了松花江流域全部采样点的生物完整性评价得分。结果显示,松花江流域内60%区域生物状态存在不同程度的损害。另外,B-IBI能够综合反映松花江大型底栖动物群落多样性、生境质量、理化水质等,具有一定的适用性。     

洪泽湖水体富营养化时空分布特征与影响因素分析

通过2014年—2017年对洪泽湖12个水质断面定期调查,采用营养状态指数(TLI)综合评价其水体富营养状态,同时应用主成分分析方法(PCA)分析其富营养化状态的时空变化特征。结果表明,洪泽湖70%以上的调查断面水质全年处于轻度富营养化状态,夏季是其富营养化最严重的季节;洪泽湖年内水体水质差异较大,而其水华特征并未呈现明显差异;洪泽湖富营养化很大程度上受制于营养盐的积累程度,并与湖泊透明度呈现极显著的负相关关系(p0.001),与湖水pH值呈现极显著的正相关关系。     

溢油多环芳烃模糊指数的研究

通过用氧化铝柱层析和等梯度呷醇：水=85％：15％）反相高效液相色谱（C18硅烷柱）紫外检测器254nm,测定30多种油品和我国海洋环境油类样品中的多环芳烃（PAHs）,建立了溢油PAHs模糊指数结果表明,油类PAHs响应因子和相对保留值的变异系数分别在8.4％－16.5％和0.00％－5.4％之间,回收率在74.6％－111.2％之间,精密度和准确度较好;海洋环境油类的多环芳烃模糊指数值（0.00383－0.01839）与润滑油类的值（0.00106－0.00942）接近,较石油及其它产品油的值（0.06983－1.00000）低;用润滑油类作为标准油,PAHs模糊指数作为溢油芳烃类监测的指示物（指标）,可提高监测海洋环境油类的代表性和可靠性     

大气环境质量的模糊综合评判方法

分析了大气环境质量评价方法现状和模糊综合评判中存在的问题及解决办法，依据我国环境影响评价实际，提出采用单因子标准指数法和模糊综合评判法相结合的方法评价大气环境质量，并给出评价方法，步骤、结合实例说明其应用。     

预防水体黑臭的水质指标研究

水体黑臭的指标，是研究其成因，判断其黑芨科学合理地管理水体的重要内容，该文选择了与一黑臭生化过程有关的的一些参数，进行了理场和模拟试验测定研究，结果证明ＤＯ、ＢＯＤ５、硫酸还原菌数等，与水体黑臭具有较好的相关性。水体黑臭与不黑臭的临界指标为：ＣＨ－２１．５，ＤＯ＝１．８ｍｇ／Ｌ，Ｎ＝２０００个／ｍｌ，ＢＯＤ５＝１４ｍｇ／Ｌ。     

应用底栖动物为指示生物的松花江干流水生态预警研究

指示生物监测及水生态预警是利用水环境中指示物种的数量、群落结构指标和个体生理指标等描述水生态系统的健康状态,其相比于常规理化监测和预警更直接地反映水体的生态质量。本研究在松花江干流2012—2015年大型底栖无脊椎动物监测结果的基础上,结合各监测点生态质量管理目标,通过分析物种的种类、出现的频次、物种污染敏感性(耐污值),尝试提出了松花江干流监控断面以底栖动物为指示生物的水生态预警模式,研究思路和结果对流域水环境风险管理指标的拓展有积极作用。     

A study on genotoxicity of textile dyeing industry effluents from Rajshahi,Bangladesh, by the Allium cepa test

Textile dye effluents are believed to be toxic as they might exert various harmful effects on living organisms including genotoxicity. These effluents are the main source of direct and continuous input of pollutants into the aquatic ecosystems. In this study, dye effluents from a local silk dyeing industry were analysed for their genotoxic potential by the Allium cepa genotoxicity test. The A. cepa test is characterised as a genotoxicity test where the roots of A. cepa are grown in different concentrations of the test material. The macroscopic results clearly showed that the toxicity of the dye effluents prompted A. cepa root growth inhibition, and this effect increased with higher concentrations of the effluents. At the cellular level, no dividing cells were found at higher concentrations such as 60%, 80% and 100% of the effluents. However, at a lower concentration of 20%, dividing cells were identified, although the mitotic index was much lower than that of the control. Microscopic analysis showed that the dye effluents induced chromosomal aberrations at significant levels. Taken together, these results revealed that the textile dyeing industry effluents are toxic to eukaryotic cells and these dyes have genotoxic properties that can potentially lead to cancer development and adverse health conditions.