应用动态模型确定酸沉降临界负荷的探讨

任何一个天然生态系统都是一个稳定系统.在一定酸沉降量的作用下,生态系统最终会平衡在一个新的稳定状态.动态模型可以模拟不同酸沉降量下生态系统化学状态的变化趋势.根据信号与系统理论,这种趋势可以用一阶指数衰减函数进行模拟,以得到系统达到稳定状态时的化学指标值.根据不同酸沉降量和所对应的稳态化学指标值之间的剂量-响应曲线,可以求出当系统稳态化学指标值达到临界化学值时的酸沉降量,即为系统的酸沉降临界负荷.应用这种方法,以MAGIC模型为例,计算了四川峨眉山顶水和重庆南山湖泊的硫沉降临界负荷,分别为1.54和6.5     

Reconsideration on the effect of nitrogen on mixed culture polyhydroxyalkanoate production toward high organic loading enrichment history

Effect of nitrogen on mixed culture PHA production was reconsidered. Enrichment history of PHA accumulating culture was discussed. Higher PHA content and biomass growth were achieved in presence of nitrogen. Enrichment strategy toward higher PHA accumulation was investigated. Microbial community succession in PHA accumulation phase was investigated. In most of the operating strategies for mixed microbial cultures polyhydroxyalkanoate (PHA) production, moderate organic loads and low nitrogen concentrations are used, however, the real waste streams contain variable concentrations of carbon and nitrogen. To evaluate the effect of enrichment history on PHA producer and production the various carbon and nitrogen levels were utilized during the accumulation phase. Different operating strategies were applied in three sequencing batch reactors (SBRs) subjected to aerobic dynamic feeding. The maximum PHA production of the enriched cultures under nutrient excess, limitation and starvation (Cmol/Nmol ratio of 8, 40 and ∞, respectively) was evaluated in batch assays. A higher PHA content and biomass growth were achieved in the nutrients presence in comparison to the nutrient starvation condition. The cultures from the SBR treated under short sludge retention time, high organic loading rate, short cycle length (SBR#3) and nutrient excess reached the maximum PHA content (54.9%) and biomass increase (38.9%). Under nutrient limitation, the negative biomass growth was observed under nutrient starvation because of the sampling loss. The succession of microbial communities in SBRs and batch assays was analyzed using terminal restriction fragment length polymorphism. The SBR#3 had the best overall PHA production performance considering its high PHA content and productivity in all nutrient content, it indicates that nitrogen has a substantial impact on PHA yield especially when high organic loading rate enrichment history is involved.     

Distribution and assessment of mercury (Hg) in surface sediments of Futian mangrove forest,China

Environmental Geochemistry and Health - To investigate the distribution of mercury (Hg) in Futian mangrove wetland, surface sediments from land to sea were collected, including Kandelia obovata,...     

Structural and technological determinants of carbon intensity reduction of China’s electricity generation

Environmental Science and Pollution Research - Electricity generation is the largest sector with decarbonization potential for China and the world. Based on the new emission factors, this paper...     

水体颗粒物以及土壤对有机物吸附常数的测定

本文介绍了用批量平衡测定水体悬浮颗粒物以及土壤对有机物吸附常数的测定方法，并给出实例和方法的注意事项。     

广西涠洲岛沉凝灰岩土壤粘粒矿物的研究

用X射线衍射分析和电子显微镜分析,对涠洲岛沉凝灰岩母质发育土壤的两个典型剖面八个土样的粘粒矿物进行分析研究。结果表明,离火山口距离不同的两个剖面土壤粘粒矿物组成不同,1号剖面以2:1型粘粒矿物为主,2号剖面则以1:1型粘粒矿物为主;结合其它分析结果,讨论了两个剖面土壤粘粒矿物组成不同的原因、对土壤有关特性的影响及其与土壤形成和分类的关系。     

Governance approach to China's environmental challenges: Towards a theoretical synthesis

This paper reviewed recent research in environmental governance as a response to environmental challenges at various spatial, temporal and administrative scales. It documented the shift of approach from regulation to governance, and attempted to provide a comprehensive understanding why and how the transformation occurred. It also described major factors and forces of environmental governance, and discussed research advance in environmental governance theory. Finally, this paper summarized recent research findings on environmental governance in China, and listed policy recommendation for enhancing the governance.     

氯乙烯生产中的清洁生产分析

结合氯乙烯清洁生产中存在的实际问题,重点对氯乙烯工业生产全过程涉及的工艺技术路线与技术装备的先进性进行分析。通过不同生产工艺的纵向比对,及先进工艺的不同专利技术间的横向对比,对氯乙烯的生产工艺进行清洁生产的分析与评价。     

珠江河口水体的二氧化碳

本文根据1987年2月至1988年2月每月一次的调查资料,通过测定pH和碱度计算了珠江河口二氧化碳各分量,讨论了ΣCO_2,溶解CO_2与盐度、温度,叶绿素-a 和溶解氧饱和度的关系。     

农药和其它有机化合物环境参数的相关性及其预测

农药和其它有机化合物的水溶解度、正辛醇／水分配系数、有机碳吸附常数和生物浓缩因子等物化参数之间存在着明显的相关性，有机化合物的水溶解度与其正辛醇／水分配系数、有机碳吸附常数和生物浓缩因子呈负相关；正辛醇／水分配系数与有机碳吸附常数和生物浓缩因子呈正相关。本文所建立的数学关系式能较好地预测未知化合物的环境特性。