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Removal of Copper from Acid Mine Drainage (AMD) or Acid Rock Drainage (ARD)

Journal of Water Resource and Protection 2021年第7期13卷 435-454页

作者： Agabu Shane Xinyang Xu John Siame Alick Nguvulu Tewodros Mitiku Tena Musango Lungu Sydney Chinyanta jackson kawala Victor Mwango Bowa Brian Chirambo Department of Mining Engineering School of Mines and Mineral Sciences Copperbelt University Kitwe Zambia Department of Environmental Engineering College of Natural Resources and Civil Engineering Northeastern University Shenyang China Department of Chemical Engineering School of Mines and Mineral Sciences Copperbelt University Kitwe Zambia Department of Geomatics Engineering School of Mines and Mineral Sciences Copperbelt University Kitwe Zambia Department of Environmental Engineering School of Mines and Mineral Sciences Copperbelt University Kitwe Zambia

Acid mine drainage is wastewater from a mine having a low pH and an elevated level of dissolved heavy metals. These metals are harmful to aquatic, animal and human life. This paper looks at the removal of copper from acid mine drainage using ion exchange to less than 1 mg/l. A weak acidic cation resin was used. Spectrophotometric determination of copper with sodium diethyldithiocarbamate was used to determine the copper concentrations in the treated water. Using regression analysis, the experimental results gave a correlation coefficient of 0.977 and a coefficient of determination of 99.5%. Results indicated that the higher the flows rate the shorter the period after which the copper concentration in the treated water reaches 1 mg/l. At pH 3.85 and 5.09, the resin performed better and at pH above 6.62 and between pH 3.0 and below the resin’s does not perform well. The higher the resin height the greater is the resin exchange capacity and the longer it takes for the copper concentration to reach 1 mg/l in the treated water. The higher the wastewater copper concentration the shorter the time it takes the resin to reach 1 mg/l. The results for this experiment indicated that acid mine drainage can be treated well by ion exchange resins, but it is also very important to establish suitable operating conditions.

关键词： Acid Mine Drainage Copper Ion Exchange Resin and Spectrophotometry

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Surface Water Quality Response to Land Use Land Cover Change in an Urbanizing Catchment: A Case of Upper Chongwe River Catchment, Zambia

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Journal of Geographic Information System 2021年第5期13卷 578-602页

作者： Alick Nguvulu Agabu Shane Claude S. Mwale Tewodros M. Tena Phenny Mwaanga John Siame Brian Chirambo Musango Lungu Frank Mudenda Dickson Mwelwa Sydney Chinyanta jackson kawala Victor Mwango Bowa Levi S. Mutambo Nicholas Okello Charles Musonda Department of Geomatics Engineering Copperbelt University Kitwe Zambia Department of Mining Engineering Copperbelt University Kitwe Zambia Department of Environmental Engineering Copperbelt University Kitwe Zambia Department of Chemical Engineering Copperbelt University Kitwe Zambia Department of Civil Engineering University of Pretoria Pretoria South Africa Department of Civil and Environmental Engineering University of Zambia Lusaka Zambia Business and Information Technology Department Cavendish University Lusaka Zambia

The Upper Chongwe River Catchment has recently been overexploited for water resources with increased complaints by various water users about the deteriorating quality of surface water within the sub-catchment. This study was motivated by the need to investigate and understand the response of surface water quality to land use land cover (LULC) change due to urbanization. Water samples, collected at 9 sampling sites from 2006 to 2017, were analyzed for water quality using the weighted arithmetic water quality index and trend using the Mann-Kendall statistics. LULC change is detected and analyzed in ERDAS Imagine 2014 and ArcGIS 10.4 using 2006 Landsat 5 TM and 2017 Landsat 8 OLI imageries. The relationship between LULC change and water quality was performed with multiple regression analysis and Pearson correlation. The results reveal that Built-up area, Grassland and surface water increased by 5.48%, 13.34% and 0.03% respectively while Agricultural land and Forest Land decreased by −13.41% and −5.42% respectively. The water quality index ranged from 43.04 to 110.40 in 2006 and from 170 to 430 in 2017 indicating a deterioration in the quality of surface water from good to unsuitable for drinking at all the sampled sites. Built-up/bare lands exhibited a significant positive correlation with EC (R2 = 0.61, p ≤ 0.05), turbidity (R2 = 0.69, p ≤ 0.05), TDS (R2 = 0.61, p ≤ 0.05), Cl (R2 = 0.62, p ≤ 0.05) and a significant negative correlation with NH4 (R2 = −0.729, p ≤ 0.05). Agriculture exhibited a significant positive correlation with turbidity (R2 = 0.71, p ≤ 0.01) and Fe (R2 = 0.75, p ≤ 0.01. Forest cover correlated negatively with most of the water quality parameters apart

关键词： Water Quality LULC Change Water Quality Index River Catchment Watershed

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Depression,suicidality and associated risk factors among police officers in urban Tanzania:a cross-sectional study

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General Psychiatry 2021年第3期34卷 135-142页

作者： Belinda jackson Njiro Harrieth Peter Ndumwa Charles Joseph Msenga Thomas kawala Ezekiel Matola Juhudi Mhonda Hillary Corbin Omary Ubuguyu Samuel Likindikoki School of Medicine Muhimbili University of Health and Allied SciencesDar es SalaamTanzaniaUnited Republic of Medical Unit Tanzania Police ForceDar es SalaamTanzaniaUnited Republic of National NCD Prevention and Control Program Ministry of HealthCommunityDevelopmentGenderElderly and ChildrenDodomaTanzaniaUnited Republic of

Background The WHO has classified depression as a disease of public *** officers are a particular subpopulation group that is at an increased risk for mental health *** study examined the prevalence of depression,suicidality and associated risk factors among police officers in urban *** The aim of this study was to examine the prevalence of depression,suicidality and associated risk factors among police officers in *** A cross-sectional study was conducted between April 2019 and October 2020 among 550 participants in Dar es Salaam recruited using a multistage cluster sampling *** Patient Health Questionnaire-9 was used to screen for depression and *** Interpersonal Support Evaluation List-12 tool was used to measure perceived social *** statistics were summarised using frequencies and *** and multivariate analyses were used to establish associations between predictors of interest,depression and *** There were 497 participants in the *** these,76.6%(376 of 491)were men,and the median(IQR)age was 37.0(17)*** 19.8%(96 of 486)of the police officers screened positive for depression and 15.4%(75 of 413)for suicidality.A significant proportion was either moderately(29 of 96,30.2%)or severely depressed(8 of 75,10.7%).Of those who experienced suicidal thoughts,10.7%(8 of 75)reported having daily suicidal *** low social support was associated with an increased risk of reporting depression(adjusted OR(aOR):28.04,95%CI:8.42 to 93.37,p<0.001)and suicidality(aOR:10.85,95%CI:3.56 to 33.08,p<0.001)as compared with those with high perceived social *** The magnitude of depression and suicidality among police officers in urban Tanzania is alarmingly *** study findings indicate the need for routine screening for depression and suicidality among police officers and design appropriate mental health responsive services in thi

关键词： routine sectional urban

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Surface Water Quality Response to Land Use Land Cover Change in an Urbanizing Catchment: A Case of Upper Chongwe River Catchment, Zambia

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Journal of Geographic Information System（地理信息系统） 2021年第5期

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