Biostyr曝气生物滤池处理城市污水的沿程生化特性

青岛市麦岛污水处理厂采用曝气生物滤池(BAF)处理城市污水,以稳定运行的Biostyr为研究载体,考察滤池COD、NH3-N、SS和细菌数量等生化特性的沿程变化.结果表明,在气水比为4∶1～5∶1、进水COD负荷为2.5 ～3.7 kg/(m3·d)、进水NH3-N负荷为0.18～0.57 kg/(m3·d)时,滤池对COD的降解主要在150 cm填料以下处,COD的去除率可达58.9％;NH3-N去除率沿滤柱高度的变化与COD有所不同,在100 cm以下填料处,NH3-N的去除率仅为3.6％,在100 ～350 cm填料之间,NH3-N的去除率增加迅速,可达56.1％;对SS的去除主要发生在100 cm填料以下,去除率达51.7％.     

Amphibians and agricultural chemicals: Review of the risks in a complex environment

Agricultural landscapes, although often highly altered in nature, provide habitat for many species of amphibian. However, the persistence and health of amphibian populations are likely to be compromised by the escalating use of pesticides and other agricultural chemicals. This review examines some of the issues relating to exposure of amphibian populations to these chemicals and places emphasis on mechanisms of toxicity. Several mechanisms are highlighted, including those that may disrupt thyroid activity, retinoid pathways, and sexual differentiation. Special emphasis is also placed on the various interactions that may occur between different agro-chemicals and between chemicals and other environmental factors. We also examine the indirect effects on amphibian populations that occur when their surrounding pond communities are altered by chemicals.     

低温对生物接触氧化反应器硝化性能的影响

分散型污水生物处理技术在我国北方冬季低温期容易出现硝化性能下降的问题。构建2个平行运行的生物接触氧化反应器,以生活污水为原水重点考察了降温过程对反应器硝化性能的影响。当水温从20 ℃降至10 ℃时, 反应器出水COD浓度比较稳定,但NH4+-N浓度开始出现上升。将水力停留时间从8 h延长至14 h后,获得了完全硝化的效果,而且进一步将水温降低至5 ℃时,硝化效果没有受到明显影响。硝化速率测定结果显示,5 ℃生物接触氧化污泥与10 ℃污泥几乎保持了相同的比硝化速率。高通量测序结果表明,降温过程中,生物接触氧化污泥保留了数量庞大的核心种属;同时硝化细菌种群丰度表现为长期低温条件下的部分富集。结果表明,适当延长水力停留时间,生物接触氧化反应器可以在5 ℃水温下获得良好的硝化效果。     

Temporal trends in the bioaccumulation of trace metals in herring, sprat, and cod from the southern Baltic Sea in the 1994–2003 period

This study is based on raw data obtained from 1 225 samples of herring (Clupea harengus), sprat (Sprattus sprattus), and cod (Gadus morhua) collected in the 1994–2003 period from the Polish coastal zone of the Baltic Sea. This paper presents the results of investigations of the contents of Cu, Zn, Cd, Pb, Hg, and As in fish. The aim was to identify temporal trends in trace metal contamination and variations in the concentrations of Hg in the flesh of herring, sprat, and cod of different lengths. A positive correlation between fish length and Hg concentration was noted for cod, sprat, and herring. The temporal trend analyses of heavy metal concentrations in the fish in the 1994–2003 period indicated ten significant downward trends out of eighteen tests; these referred to concentrations of Cd, Hg, and Pb in all the species studied, and to As in sprat. Concentrations of Cu and Zn remained stable in all the species studied, as did As in herring and cod. No upward trends were detected in the concentration of trace metals in the fish studied. Smaller scale temporal variations in concentrations of some elements were also observed and were associated with natural events, such as increased river discharge resulting from floods. The most likely factors which contributed to the observed downward trends in heavy metals concentrations in fish could possibly stem from lesser quantities of Cd, Pb, and Hg being introduced to the Baltic Sea with the waters of rivers from Baltic countries, including Poland, and atmospheric depositions in the 1994–2003 period. Diminishing trends of concentrations of these elements in Baltic Sea waters are also evidence of this. These facts might indicate that advantageous changes are occurring in the concentrations of heavy metals in the southern Baltic environment.     

Long-term trends in mercury and PCB congener concentrations in gannet (Morus bassanus) eggs in Britain

Gannet (Morus bassanus) eggs from Bass Rock (North Sea) and Ailsa Craig (eastern Atlantic) were monitored for PCB congeners (1990-2004) and total mercury (1974-2004). Congener profiles for both colonies were dominated by PCBs 153, 138, 180, 118 and 170. All declined in concentration at Ailsa Craig but some (153, 170, 180) remained stable or increased slightly at Bass Rock. Egg congener concentrations at Bass Rock were typically 10-fold higher than at Ailsa Craig by 2002, and Principal Component Analysis indicated that colony differences were driven by the dominant congeners. Egg mercury concentrations were significantly lower at Bass Rock than at Ailsa Craig and temporal trends differed, there being a significant decline at Ailsa Craig but a marginal increase at Bass Rock. Our results suggest there may be differences in contamination between the eastern Atlantic and North Sea and/or there are colony differences in prey selection and associated contaminant loads.     

Insights for Integrated Conservation from Attitudes of People toward Protected Areas Near Hwange National Park,Zimbabwe

Increase in human settlements at the edge of protected areas (PAs) is perceived as a major threat to conservation of biodiversity. Although it is crucial to integrate the interests of surrounding communities into PA management, key drivers of changes in local populations and the effects of conservation on local livelihoods and perceptions remain poorly understood. We assessed population changes from 1990 to 2010 in 9 villages located between 2 PAs with different management policies (access to natural resources or not). We conducted semi‐directive interviews at the household level (n =217) to document reasons for settlement in the area and villager's attitudes toward the PAs. We examined drivers of these attitudes relative to household typology, feelings about conservation, and concerns for the future with mixed linear models. Population increased by 61% from 2000 to 2010, a period of political and economic crisis in Zimbabwe. Forty‐seven percent of immigrants were attracted by the area; others had been resettled from other villages or were returning to family lands. Attitudes toward PAs were generally positive, but immigrants attracted by the area and who used resources within the PA with fewer restrictions expressed more negative attitudes toward PAs. Household location, losses due to wild animals, and restrictions on access to natural resources were the main drivers of this negative attitude. Profit‐seeking migrants did not expect these constraints and were particularly concerned with local overpopulation and access to natural resources. To avoid socio‐ecological traps near PAs (i.e., unforeseen reduced adaptive capacity) integrated conservation should address mismatches between management policy and local expectations. This requires accounting for endogenous processes, for example, local socio‐ecological dynamics and values that shape the coexistence between humans and wildlife. Percepciones para Conservación Integrada a Partir de las Actitudes de las Personas hacia Áreas Protegidas cerca del Parque Nacional Hwangem Zimbabwe     

Species- and tissue-specific accumulation of Dechlorane Plus in three terrestrial passerine bird species from the Pearl River Delta, South China

Little data is available on the bioaccumulation of Dechlorane Plus (DP) in terrestrial organisms. Three terrestrial passerine bird species, light-vented bulbul, long-tailed shrike, and oriental magpie-robin, were collected from rural and urban sites in the Pearl River Delta to analyze for the presence of DP and its dechlorinated products in muscle and liver tissues. The relationships between trophic level and concentration and isomeric composition of DP in birds were also investigated based on stable nitrogen isotope analysis. DP levels had a wide range from 3.9 to 930 ng g⁻¹ lipid weight (lw) in muscle and from 7.0 to 1300 ng g⁻¹ lw in liver. Anti-Cl₁₁-DP and syn-Cl₁₁-DP, two dechlorinated products of DP, were also detected in bird samples with concentrations ranged between not detected (nd)-41 and nd-7.6 ng g⁻¹ lw, respectively. DP preferentially accumulated in liver rather than in muscle for all three bird species. Birds had significantly higher concentrations of DP in urban sites than in rural sites (mean, 300 vs 73 ng g⁻¹ lw). The fractions of anti-DP (f_anti) were higher in birds collected in rural sites than in urban sites. Significant positive correlation between DP levels and δ¹⁵N values but significant negative correlation between f_anti and δ¹⁵N values were found for birds in both urban and rural sites, indicating that trophic level of birds play an important role in determining DP level and isomeric profile.     

A/O膜生物反应器处理垃圾渗滤液的试验研究

本文通过试验采用A/O膜生物反应器对垃圾渗滤液进行了处理,结果表明:当厌氧水力停留时为15 h、好氧水力停留时间为30 h、回流比为300%～400%时,CODcr、BOD5、氨氮及TN的平均去除率分别为85.2%、91.6%、88%和43.9%;人工投加碳源后,TN的平均去除率提高到77.7%;在反应器好氧区中形成了...     

北京市机动车排放趋势与协同控制情景分析

为了分析北京市长时间尺度的机动车尾气排放趋势,研究机动车排放大气污染物和温室气体的协同控制效应。应用COPERT 5模型构建2005—2020年北京市机动车污染物CO、NO_x、VOCs、PM_2.5和CO₂、CH₄、N₂O的排放清单,以2020年为基准年,设置5种减排情景评估2025年各情景下的机动车污染物减排效果,并利用协同减排弹性系数法和坐标系法分别分析了大气污染物与温室气体的协同效应。结果表明：CO₂排放增长趋势显著,相比2005年,2020年其排放增长率达到85.25%,而其他污染物相比2005年均呈下降趋势。不同控制情景下,北京市机动车大气污染物和温室气体排放量相比于基准情景(BAU)均具有减排效果,综合控制情景(RIS)减排效果最好。从协同减排弹性系数法和坐标系法分析结果看,不同控制情景下大气污染物和温室气体均具有协同效应,且RIS下协同效应最优。未来北京市应积极采取综合控制对策,兼顾统筹各种减排措施,为尽快实现降碳减污协同治理和绿色低碳经济社会转型奠定基础。

     

安徽省城市用地扩张及城市化特征研究

根据安徽省1991-2005年城市建成区的扩展情况，从城市空间扩展动态度来对安徽省17个地级市进行城市扩展分类，由此得到城市空间扩展不同梯度的扩展类型。结合社会经济统计数据对安徽城市化特征进行分析，发现安徽省城市化取得了显著的成就，并在此基础上提出了面临的挑战，为城市化进程及城市土地资源的可持续发展提供科学依据。