Assessment of air pollution in residential areas : a case study of Kinondoni Municipality, Tanzania

Published ArticleAir pollution, just like any other type of pollution, produces harmful effects to man and his environment. In spite of knowing this, many less industrialised countries of the world have no air quality monitoring strategies in place. Consequently, documented evidence of air pollution studies in such countries is scarce. This is the case in Tanzania. This scenario is made worse by lack of scientific tools which could aid in identifying air pollution-prone areas with a view to aiding town planners in locating safe sites for schools, hospitals and residential areas as well as parks. In this paper, we present results of a study carried out in the city of Dar-es-Salaam, Tanzania on air pollution in residential areas. Results show significant air pollution in the studied areas. Moreover, both adults and children are at risk due to lead pollution in the air

Waste management practices in Nigeria: Impacts and mitigation

We reviewed the current state of waste management practices in Nigeria using examples from different parts of the country. Commonly practiced waste disposal methods in Nigeria, such as burial, open-air burning, and open dumping, were found to be ineffective and detrimental to public health and the environment. It was also shown that waste management cannot be successfully operated as a social service. Rather, the generator of waste must be held responsible. Problems confronting efficient waste management in Nigeria include the proliferation of unplanned settlements, traffic congestion, insecurity, and ignorance. An experimental model being used in Lagos State for the management of wastes may be the solution. Given the rate of population growth, industrialization, and urbanization, forward-looking and effective waste management plans need to be set in motion for the protection of public health. Such plans must involve all stakeholders, including the waste generators, the private sector, the informal sector, and regulatory agencies

Application of Water Recovery Option for Agricultural Use in Developing Countries: Case Study of a Nigerian Community

Africa’s current population of 1 billion people is estimated to increase to 1.8 billion in 2050. This compliments the fastest growing population rate which stands at 2.4 %. Moreover, 40% of Africa’s land is semi-arid while another 27% is desert leaving a common conclusion that water is a crucial resource with tremendous implication on African development. The rapid urbanization and growing population in African cities has resulted in new water management challenges. About 85% of water in Africa is used on agriculture. Only 10% and 5% are used in households and industries respectively. The objective of this study is to appraise the different methods available for water collection, treatment and reuse for agricultural purposes in parts of Nigeria. The study involves the assessment of available methods used by farmers for the promotion of agriculture. The study deployed the use of in-depth interviews, onsite investigation and group discussions in various areas in a typical semi-urban city in southwest Nigeria. The procedure combines descriptive data on the amount of water used per day on farms, sources of the water used, purpose of the water used and the size of the farm. Results of this study showed that a comparatively large volume of water being used for agricultural sustenance is withdrawn from natural aquifer storages. This poses a challenge and threatens global effort of achieving the United Nation’s water-related Millennium Development Goals (MDG 7c) in developing countries aimed at making potable water available for millions of people. It was concluded that a sustainable, de-centralized wastewater treatment plant can be deployed for irrigation purposes in order to reduce pressure from agriculture on groundwater resources and, at the same time, encourage artificial recharge of wells. Also, adequate and efficient water management procedures which would help to overcome emerging water challenges were proposed

EVALUATION OF TWO-STAGE SUBSURFACE FLOW CONSTRUCTED WETLANDS FOR ABATTOIR WASTEWATER MANAGEMENT

Abattoir wastewater is high in organic content, the waste recovery and treatment facility is expensive and this results in indiscriminate dumping into streams without adequate treatment. The effectiveness of using a two-stage subsurface flow constructed wetland to treat abattoir effluent was examined in this study. Diluted abattoir wastewater from Lafenwa Abattoir, Abeokuta, Ogun State, Nigeria was fed into a two-stage Vegetated Subsurface Bed Constructed Wetlands (VSBCW). The VSBCW consisted of 500 mm deep 10-15 mm diameter granite with 150 mm thick overlay of well graded sand planted with locally available Vetiveria nigritana. Grab samples were collected at selected points along Ogun river and measurement of physico-chemical parameters such as: Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD5), Electrical Conductivity (EC), Total Dissolved Solids (TDS) and Total Suspended Solid (TSS) of the influent and effluent from the VSBCW were carried out. Irrigation with water and diluted abattoir wastewater to examine the variation in plant growth rate was also investigated. The results revealed a pollution load reduction as the wastewater moves away from the discharge point but inadequate to meet the FEPA (1991) standard for wastewater discharge into rivers. The VSBCW was observed to reduce the concentration of BOD5, COD, EC, TDS and TSS in the abattoir wastewater by 88.71, 87.28, 45.72, 56.89 and 72.27 % respectively. The growth rate of the V. nigritana reduced by 1.9% when irrigated with abattoir wastewater. The study revealed that locally available V. nigritana in VSBCW is effective in abattoir wastewater treatment and could be use to curtail the pollution caused by discharge of untreated wastewater into rivers.     &nbsp

LIFE-CYCLE COST ANALYSIS OF RECLAIMED ASPHALT PAVEMENT FOR SUSTAINABLE ROAD REHABILITATION

The construction of pavements requires a significant amount of non-renewable materials and energy. Recycling of asphalt pavements is a valuable approach for technical, economic and environmental reasons. The use of reclaimed asphalt pavement (RAP) is being favoured over virgin materials due to increasing cost of asphalt, the scarcity of quality aggregates and the pressing need to preserve the environment. This paper present a life cycle cost analysis of recycled pavement material for sustainable road rehabilitation on Jabulani Selepe road in Bethal, Mpumalanga Province of South Africa.  Long term cost effects of recycled materials was determined in pavement design; life-cycle cost analysis (LCCA) was carried out on recycled materials, alternative recycling materials and conventional method. The present worth of cost (PWOC) for recycling and conventional method was used to determine the most viable option for construction and maintenance. Agency cost, initial rehabilitation, maintenance, future and salvage cost while the users cost which include construction delays, accident cost, time and vehicle operating cost was done. The result showed that LCCA identifies recycled RAP as the lowest cost pavement alternative. The PWOC for RAP and alternative recycling material was 50.90% and 41.48% respectively when compared with conventional method. Thus, using large amount of RAP could turn these asphalt mixes into good alternative to hot mix asphalt in environmental terms and cost-effective means to road rehabilitation than that of a conventional project

Recommendations for dealing with waste contaminated with Ebola virus: a Hazard Analysis of Critical Control Points approach

Objective To assess, within communities experiencing Ebola virus outbreaks, the risks associated with the disposal of human waste and to generate recommendations for mitigating such risks. Methods A team with expertise in the Hazard Analysis of Critical Control Points framework identified waste products from the care of individuals with Ebola virus disease and constructed, tested and confirmed flow diagrams showing the creation of such products. After listing potential hazards associated with each step in each flow diagram, the team conducted a hazard analysis, determined critical control points and made recommendations to mitigate the transmission risks at each control point. Findings The collection, transportation, cleaning and shared use of blood-soiled fomites and the shared use of latrines contaminated with blood or bloodied faeces appeared to be associated with particularly high levels of risk of Ebola virus transmission. More moderate levels of risk were associated with the collection and transportation of material contaminated with bodily fluids other than blood, shared use of latrines soiled with such fluids, the cleaning and shared use of fomites soiled with such fluids, and the contamination of the environment during the collection and transportation of blood-contaminated waste. Conclusion The risk of the waste-related transmission of Ebola virus could be reduced by the use of full personal protective equipment, appropriate hand hygiene and an appropriate disinfectant after careful cleaning. Use of the Hazard Analysis of Critical Control Points framework could facilitate rapid responses to outbreaks of emerging infectious disease

Pregnancy rates among female participants in phase 1 and phase 2A AIDS vaccine clinical trials in Kenya

Background: Female participants in AIDS candidate vaccine clinical trials must agree to use effective contraception to be enrolled into the studies, and for a specified period after vaccination, since the candidate vaccines’ effects on the embryo or foetus are unknown.Objectives: To review data on female participants’ pregnancy rates from phase I and IIA AIDS vaccine clinical trials conducted at the Kenya AIDS Vaccine Initiative (KAVI) and to discuss the challenges of contraception among female participants.Design: Descriptive observational retrospective study.Setting: KAVI clinical trial site, Kenyatta National Hospital and University of Nairobi, Kenya.Subjects: Thirty nine female participants were enrolled into these trials. They received family planning counselling and were offered a choice of different contraceptive methods, as per the protocols. All contraception methods chosen by the participants were offered at the study site at no cost to the participant.Results: Four women conceived during the study period when pregnancies were to be avoided. All four had opted for sexual abstinence as a contraceptive method, but reported having been coerced by their partners to have unprotected sexual intercourse.Conclusion: Abstinence is clearly not a reliable contraceptive option for women in developing-country settings. Effective female-controlled contraceptives, administered at the clinical trial site, may empower female participants to better control their fertility, leading to more complete clinical trial data

Corrigendum: Three spatially separate records confirm the presence of and provide a range extension for the giant pangolin Smutsia gigantea in Kenya (Oryx (2022) DOI: 10.1017/S0030605322000126)

In the original publication of this article, the list of authors was incomplete, with only the following authors listed: Tommy Sandri, Claire Okell, Stuart Nixon, Naomi Matthews, Fred Omengo, James Mathenge, Stephen Ndambuki, Daniel W.S. Challender and Bradley Cain. The correct author list is: Tommy Sandri, Claire Okell, Stuart Nixon, Naomi Matthews, Fred Omengo, James Mathenge, Stephen Ndambuki, Daniel W.S. Challender, Richard Chepkwony, Patrick Omondi, Shadrack Ngene and Bradley Cain The article has been updated to include the correct author details and add the ORCID iD of Shadrack Ngene

Groundwater levels forecasting using machine learning models: A case study of the groundwater region 10 at Karst Belt, South Africa

The crucial role which groundwater resource plays in our environment and the overall well-being of all living things can not be underestimated. Nonetheless, mismanagement of resources, over-exploitation, inadequate supply of surface water and pollution have led to severe drought and an overall drop in groundwater resources’ levels over the past decades. To address this, a groundwater flow model and several mathematical data-driven models have been developed for forecasting groundwater levels. However, there is a problem of unavailability and scarcity of the on-site input data needed by the data-driven models to forecast the groundwater level. Furthermore, as a result of the dynamics and stochastic characteristics of groundwater, there is a need for an appropriate, accurate and reliable forecasting model to solve these challenges. Over the years, the broad application of Machine Learning (ML) and Artificial Intelligence (AI) models are gaining attraction as an alternative solution for forecasting groundwater levels. Against this background, this article provides an overview of forecasting methods for predicting groundwater levels. Also, this article uses ML models such as Regressions Models, Deep Auto-Regressive models, and Nonlinear Autoregressive Neural Networks with External Input (NARX) to forecast groundwater levels using the groundwater region 10 at Karst belt in South Africa as a case study. This was done using Python Mx. Version 1.9.1., and MATLAB R2022a machine learning toolboxes. Moreover, the Coefficient of Determination (R2);, Root Mean Square Error (RMSE), Mutual Information gain, Mean Absolute Percentage Error (MAPE), Mean Squared Error (MSE), Mean Absolute Error (MAE), and the Mean Absolute Scaled Error (MASE)) models were the forecasting statistical performance metrics used to assess the predictive performance of these models. The results obtained showed that NARX and Support Vector Machine (SVM) have higher performance metrics and accuracy compared to other models used in this study

Recommendations for dealing with waste contaminated with Ebola virus: a Hazard Analysis of Critical Control Points approach

Objective To assess, within communities experiencing Ebola virus outbreaks, the risks associated with the disposal of human waste and to generate recommendations for mitigating such risks. Methods A team with expertise in the Hazard Analysis of Critical Control Points framework identified waste products from the care of individuals with Ebola virus disease and constructed, tested and confirmed flow diagrams showing the creation of such products. After listing potential hazards associated with each step in each flow diagram, the team conducted a hazard analysis, determined critical control points and made recommendations to mitigate the transmission risks at each control point. Findings The collection, transportation, cleaning and shared use of blood-soiled fomites and the shared use of latrines contaminated with blood or bloodied faeces appeared to be associated with particularly high levels of risk of Ebola virus transmission. More moderate levels of risk were associated with the collection and transportation of material contaminated with bodily fluids other than blood, shared use of latrines soiled with such fluids, the cleaning and shared use of fomites soiled with such fluids, and the contamination of the environment during the collection and transportation of blood-contaminated waste. Conclusion The risk of the waste-related transmission of Ebola virus could be reduced by the use of full personal protective equipment, appropriate hand hygiene and an appropriate disinfectant after careful cleaning. Use of the Hazard Analysis of Critical Control Points framework could facilitate rapid responses to outbreaks of emerging infectious disease