Evaluation of Four Anthropogenic Activity Impacts on Heavy Metal Quality of the Kumba River in the South West Region of Cameroon

Anthropogenic activities have contributed to pollution of water bodies through deposition of diverse pollutants amongst which are heavy metals. These pollutants, which at times are above the maximum concentration levels recommended, are detrimental to the quality of the water, soil and crops (plant) with subsequent human health risks. The objective of the work was to evaluate the impacts of human-based activities on the heavy metal properties of surface water with focus on the Kumba River basin. Field observations, interviews, field measurements and laboratory analyses of different water samples enabled us to collect the different data. The results show four main human-based activities within the river basin (agriculture, livestock production, domestic waste disposal and carwash activities) that pollute surface water. Approximately 20.61 tons of nitrogen and phosphorus from agricultural activities, 156.48 tons of animal wastes, 2517.5 tons of domestic wastes and 1.52 tons of detergent from carwash activities were deposited into the river each year. A highly significant difference at 1% was observed between the upstream and downstream heavy metal loads in four of the five heavy metals tested except for copper that was not significant. Lead concentrations were highest in all the activities with an average of 2.4 mg∙L−1 representing 57.81%, followed by zinc with 1.596 mg∙L−1 (38.45%) and manganese with 0.155 mg∙L−1 (3.74%) for the different anthropogenic activities thus indicating that these activities highly lead to pollution of the Kumba River water. The level of zinc and manganese was significantly influenced at ρ 005 by anthropogenic activities though generally the variations were in the order: carwash (3.196 mg∙L−1) < domestic waste disposal (3.347 mg∙L−1) < agriculture (4.172 mg∙L−1) < livestock (4.886 mg∙L−1) respectively and leading to a total of 14.04 tons of heavy metal pollutants deposited each day.

Displaying Water Table Levels, Flow Direction for Predicting Construction Techniques Using Geographic Information: Case Study of Kumba (South West, Cameroon)

The rapid economic growth of the town present the matter of water issue as a problem to human life human life, construction life, agriculture, etc. This study is to predict techniques of foundation construction through the displaying of the water table at the flow direction in the town of Kumba and GIS. It is characterized by a significant research question which is the level of fall and rise in groundwater levels within the town of Kumba and this influence on choice of types of foundation in construction. This study is directed to decision makers, and technicians of the construction field to develop policies facilitating the supervision when building construction foundation by informing about water level depth and its flow direction in the town. To achieve this, depths of static water levels were measured in over 200 randomly selected hand-dug wells in Kumba, after their geolocation and data were collected during the dry season (November and March 2017) and during the rainy season (between April and October 2017). Data were analyzed and treated using Microsoft Excel and GIS software us as Golden Surfer, Global Mapper, and ArcGIS. The results show variations of water level and those areas that may threaten foundation construction. Quarter as Kumba Station, Mile 1, Bulletin Street (Fongong Quarter), and parts of Fiango show that water table is to deep water and proper for the shallow foundation but very hard for water supply through borehole. Groundwater flow direction was revealed to be towards the south and southeastern parts of Kumba. The significant of the study is to propose to the technician the direct application on the field of chosen types of foundations according to the quarter and proposed groundwater supply possibilities.

Groundwater Monitoring in the Gneisso-Basaltic Fractured Rock Aquiferous Formations of Kumba, Southwest Region Cameroon: Seasonal Variations in the Aqueous Geochemistry and Water Quality

The objective was to determine and monitor seasonal changes during four hydrological seasons: Wet season (September), Wetdry season (December), Dry season (March) and Drywet season (June) in the groundwater aqueous geochemistry and its domestic-agro-industrial quality using physicochemical parameters and hydrogeochemical tools: Temperature, Electrical Conductivity EC, pH, Total dissolved solids TDS, Ionic ratios, Gibbs diagrams, Piper diagrams Durov diagrams, total hardness HT, Water quality index WQI, Sodium adsorption ratio SAR, Percent Sodium %Na, Kelly’s Ratio KR, permeability index PI, Magnesium adsorption ratio MAR, Residual sodium carbonate RSC and Wilcox diagram. Field physicochemical parameters ranged from: Wet season;pH 3.9 - 6.9;Temperature, 23.3°C - 29.1°C;EC, 10 - 1900 μS/cm;TDS, 6.7 - 1273 mg/L;Wetdry, pH, 5.7 - 11.7;Temperature, 23.6°C - 28.3°C;EC, 1 - 1099 μS/cm, TDS, 0.67 - 736.33 mg/L;Dry pH, 5.7 - 13.1;Temperature, 26.3°C - 30.2°C;EC, 12 - 770 μS/cm, TDS, 8.04 - 515.9 mg/L and Drywet, pH, 4 - 7.4;Temperature, 25.8°C - 30.7°C;EC, 10 - 1220 μS/cm, TDS, 6.7 - 817.4 mg/L. Seventy-two groundwater samples, 18 per season were analysed. All ionic concentrations fell below acceptable World Health Organization guidelines in all seasons. The sequence of abundance of major ions are;Wet, Ca+ > Mg2+ > Na+ = K+ > NH4+, HCO3? > Cl? > NO3? > SO42? > HPO42?;Wetdry Ca+ > K+ > Mg2+ > Na+ > NH4+, HCO3? > Cl? > SO42? > NO3? > HPO42?;Dry Ca+ > K+ > Mg2+ > Na+ > NH4+, HCO3? > Cl?> NO3? > SO42? > HPO42?;Drywet NH4+ > Ca+ > K+ > Mg2+ > Na+;Cl? > HCO3? > NO3? > SO42? > HPO42?. Groundwater ionic content was due to rock weathering and ion exchange reactions. CaSO4 is the dominant water type in Wet and Wetdry seasons;followed by CaHCO3, Na + K-Cl Wet, CaSO4 and CaHCO3 Wetdry;MgCl Dry and Drywet followed by CaCl, CaHCO3 Dry and CaSO4, CaHCO3 Dry-Wet. The dominant hydrogeochemical facies are Ca-Mg-Cl-SO4 followed by Na-K-SO4 Wet and Ca-Mg-HCO3? in all other seasons. Ion exchange, Simple dissolution and uncommon dissolution are the processes determining groundwater character. The water quality indices;WQI, HT, SAR, %Na, KR, PI, MAR,RSC and Wilcox diagrams, indicate that groundwater in Kumba is 80% - 100% excellent during the Drywet &Wet seasons, 5% - 10% unsuitable during the Wetdry & Dry seasons for domestic use while being excellent-good for Agro-Industrial uses in all other seasons. Physicochemical parameters in some areas exceeded permissible limits for drinking. All hydrogeochemical parameters vary with seasons and these variations show the impact of annual cycles of seasonal changes on the aqueous geochemistry of groundwater in Kumba.

超滤对黄金梨干酒香气成分的影响

研究超滤处理对黄金梨干酒中香气成分的影响,明确超滤过程中香气成分变化规律;将黄金梨干酒采用超滤进行处理,采用GC-MS分析处理前后酒的香气成分;研究表明:超滤前后的酒中,分别检出44和42种香气成分;超滤前,羧酸类、醇类、酯类、醛酮类和酚类化合物的相对含量分别为16.9%、40.2%、0.66%、1.39%和0.16%;超滤后,羧酸类、醇类、酯类、醛酮类和酚类化合物的相对含量为15.9%、40.4%、0.78%、1.56%和0.163%。超滤处理前后,酒的香气成分基本相同;超滤处理简单方便,对酒的香气成分影响小,是一种合适的黄金梨干酒澄清手段。

黄金梨干酒香气成分分析

利用溶剂萃取法对黄金梨干酒中的香气成分进行提取,采用气相色谱-质谱(GC-MS)联用技术对其分析,获得的黄金梨干酒总离子流色谱图中共44个峰,经过NIST98谱库联机检索,鉴定出31种化合物,约占色谱流出峰总面积的98.05%。结果表明,醇类化合物相对百分含量为78.03%,是黄金梨干酒中含量最多的一类化合物。黄金梨干酒中的主要香气化合物为β-苯乙醇,相对含量为21.78%。

超滤澄清黄金梨干酒的研究

采用超滤技术对黄金梨干酒进行处理,分析超滤过程中操作压力和操作温度等因素对膜通量的影响。结果表明,黄金梨干酒超滤时,操作压力在0.1MPa,温度30℃左右时,膜通量高。所得的黄金梨干酒澄清、颜色金黄,香气和营养成分也基本得到保持。