Environmental impact assessment of Attenda abattoir, Ogbomoso southwestern Nigeria on surface and groundwater quality using geo-electrical imaging and microbiological analysis

The impact of Attenda abattoir, Ogbomoso southwestern Nigeria on four water sources was investigated using geoelectrical imaging and microbiological analysis. 2D electrical resistivity imaging indicated groundwater contamination by leachate from the abattoir. Electrical resistivity values measured by the traverse run directly on the waste dump and other areas impacted by the waste from the abattoir are generally very low (6.68-16.7 ?m) in comparison to other positions (135-288 ?m). The total viable bacteria count of the water samples ranged from 0.49 × 10(6) to 2.85 × 10(8) cfu/ml and all samples are contaminated with coliforms with the most probable number (MPN)/100 ml ranging from 110 to ≥ 1,600 MPN/100 ml. Among bacteria isolated from the study site (n = 95), resistance to eight antibiotics ranged from 35.8% to 94%. In addition, 85% of Streptococcus agalactiae (n = 31) and Staphylococci (n = 9) showed haemolytic activity while 92% of all isolates showed β-lactamase activity. These results suggest that operations of the abattoir may impact negatively on surrounding aquatic ecosystem and endanger the health of surrounding residents who use water from the wells for domestic purposes. Furthermore, such aquatic ecosystems may serve as reservoir of antibiotic resistant bacteria.     

微波法复合絮凝剂PAFC-PAM的制备及脱色性能

研究了以三氯化铝,三氯化铁和阳离子聚丙烯酰胺为原料,在微波辐照下制备PAFC-PAM复合絮凝剂的工艺条件,探讨了pH值、复合絮凝剂投加量对活性染料模拟废水脱色率的影响,并考察了其对实际印染废水的处理效果。结果表明:在PAM/PAFC质量比为0.25、微波合成功率150W、微波时间3min制得的复合絮凝剂,浊度去除率为98.8%。在pH=8,投加量为42mg/L的最佳絮凝条件下,复合絮凝剂对模拟染料废水脱色率高达97%。与PAFC和PAM相比,PAFC-PAM具有较宽的pH适宜范围和较低的投加量且对实际印染废水的处理效果优于PAFC和PAM。     

Dynamics of land use land cover and its impact on carbon stocks in Sub-Saharan Africa: an overview

Environment, Development and Sustainability - Land use land cover change (LULCC) is a global environmental trend that plays a key role in worldwide environmental change and sustainable development....     

地铁运行引起的地面振动实测及传播规律分析

对地铁线路某区间段的地面振动进行实测,采集不同测线和不同测点处的水平方向、竖直方向加速度,并转化为傅里叶幅值谱对其进行衰减规律分析。利用公式将加速度记录换算为振级和分频振级,参照相关的国家标准分析不同距离处的振级和频率成分。对比同一加速度记录中的两对开方向列车引起的地面振动,进一步分析振动衰减的规律。所得到的结果可供地面建筑的隔振减振及城市轨道的规划和设计参考。