Heavy metal content of vegetables irrigated with mixtures of wastewater and sewage sludge in Zimbabwe: Implications for human health

There is growing public concern in Zimbabwe over the illegal cultivation of vegetables on soils amended with sewage sludge or irrigated with admixtures of sewage and sewage sludge. Excessive accumulation of heavy metals in agricultural soils may not only result in environmental contamination, but lead to elevated heavy metal uptake by crops, which may affect food quality and safety. The work reported here studied heavy metal concentrations in crops irrigated with sewage sludge and sewage/sewage sludge admixtures at Firle Municipal Farm in Harare. The crops analysed in this study are heavily contaminated with the four regulated elements Cd, Cu, Pb and Zn. This contamination is at its highest in two of the staple dietary crops maize and tsunga. Tsunga leaves contained 3.68 mg kg-1 Cd, over 18 times the permissible level by the EU standards (0.2 mg kg-1); Cu concentrations were 111 mg kg-1, 5 times the EU Standard (20 mg kg-1); concentrations of Pb were 6.77 mg kg-1, over 22 times the permissible levels allowed by both EU standards and UK guidelines (0.3 mg kg-1); Zn concentrations were 221 mg kg-1, over 4 times the guideline value (50 mg kg-1). The other plants (beans, maize, peppers and sugarcane) also contained concentrations of heavy metals above the permissible levels. Furthermore the concentrations observed in this study were higher than those reported by other workers who have examined vegetation from other contaminated sites. This study highlights the potential risks involved in the cultivation and consumption of vegetables on plots irrigated with sewage sludge, a practice which may place at risk the health of the urban population who consume these vegetables

Social work decolonisation- forays into Zimbabwe experiences, challenges and prospects

This article examines social work education and training trends in Zimbabwe based on literature review using the lens of decolonisation of social work education. The article’s objective is to consider Zimbabwean social work education and training decolonisation and implications of the concept for contemporary frontline social work practice. This will be achieved by exploring critical perspectives in current Zimbabwean social education trajectory, identifying gaps and opportunities. A social work education decolonisation agenda is also considered for creating a push towards transformational approaches in Zimbabwean social work practice decolonisation

A SURVEY PAPER ON AUTOMATED ELECTRONIC TOLLING SYSTEMS USING RADIO FREQUENCY IDENTIFICATION TECHNOLOGY

Purpose: In this paper we carry out a review on Automated e-tolling systems using RFID technology that has already been proposed by other researchers. Analysed and synthesised the researchers\u27 solutions and identifying their advantages and disadvantages, and also the gap they left that needs further research. Methodology: the approach used to conduct this review was to collect extensive peer reviewed literature on how solutions by several authors\u27 RFID technology implementation for Automated e-tolling systems helped collect road tax automatically and efficiently around the world with the effect of eliminating vehicle congestion around toll plazas. A prototype was developed to test the effectiveness of our proposed solution. Findings: This study found out that the use of RFID technology in Automated E-tolling systems is the cheapest and most effective way of collecting road tax revenue without delaying motor vehicles. Furthermore, enables vehicles to pay road tax while moving. This study also revealed that for the Automated E-tolling system to be secure and efficient the communication between RFID tag and reader has to be secured. Due to limitations in resources in cheap passive RFID tags, text steganography using Unicode zero width characters is most appropriate due to its high embedding capacity and very low processing needed. Unique contribution to theory, practice and policy: The review was able to bring out the importance of securing the communication between tag and reader thus building a system with security from design not as an afterthought. It also reveals the use of text steganography as a way of preserving tag privacy. Vehicle congestion at toll collection points has a domino effect of causing pollution to the environment, loss of productive time while waiting in the queue at toll plazas to be saved and also loss of fuel while the vehicle is idling waiting for its turn to be saved. Automated e-tolling systems using RFID technology also reduces the cost of collecting road taxes by significantly reducing the manpower needed at various toll plazas thereby making the system more efficient than the current manual or semi-automated toll collection systems currently available in Zimbabwe

Embedding the developmental approach in social work education and practice to overcome poverty: The case of Southern Africa

The article examines the extent to which social work education and practice in Eswatini, Lesotho and Zimbabwe has embedded the developmental approach to address the problem of poverty and to bring about socio-economic transformation in these countries. This is particularly significant as social work has gained traction internationally as a problem-solving profession. However, it is argued that that there is a lack of clarity conceptually about how the developmental approach should be operationalised in order to deal with the social problems afflicting African countries in general and Southern Africa in particular. Furthermore the chapter examines challenges in the implementation of the developmental approach in economically fragile contexts such as Eswatini, Lesotho and Zimbabwe. The gaps and constraints in mainstreaming developmental social work are also examined in the context of poverty, globalisation and impacts of natural disasters. Challenges experienced by frontline social workers in mobilising communities through the application of a repertoire of developmental social work approaches have also received attention. The article is based on personal experiences of the authors in teaching and practicing social work in the three countries and this is complemented by reviews and analysis of research studies and policy documents and reports on the mitigation of poverty and the developmental approach. Importantly, the article also offers pathways on the embedment of the developmental approach in social work education and practice to promote the realisation of the Sustainable Development Goals (SDGs) especially the goal relating to the eradication poverty.

A review of modeling approaches in activated sludge systems

The feasibility of using models to understand processes, predict and/or simulate, control, monitor and optimize WasteWater Treatment Plants (WWTPs) has been explored by a number of researchers. Mathematical modeling provides a powerful tool for design, operational assistance, forecast future behavior and control. A good model not only elucidates a better understanding of the complicated biological and chemical fundamentals but is also essential for process design, process start-up, dynamics predictions, process control and process optimization. This paper reviews developments and the application of different modeling approaches to wastewater treatment plants, especially activated sludge systems and processes therein in the last decade. In addition, we present an opinion on the wider wastewater treatment related research issues that need to be addressed through modeling.Key words: Mathematical modeling, water, wastewater, wastewater treatment plants, activated sludge systems

Business and Society: Determinants and Experiences of Corporate Social Responsibility Practices in Zimbabwean Extractive Industries from 2000-2015

Although a considerable Corporate Social Responsibility (CSR) knowledge base exists in Zimbabwe, there have been no comprehensive studies on CSR determinants and community CSR in Zimbabwe since 2000. This article explores the dominant narratives in CSR literature that have contributed to continuous debates in related academia, businesses, and society. Zimbabwe is resource rich, but the majority of the population is still living in abject poverty. Some have questioned whether this is indicative of a Zimbabwean resource curse. Many Zimbabweans believe that the companies benefitting from these resources should finance social programs in the country (NewsDay, 2012). This belief is a result of fiscal challenges that the government of Zimbabwe is grappling with. The article concludes by recommending pathways for sustainable CSR implantation

Determining and modeling the dispersion of non point source pollutants in Lake Victoria: A case study of Gaba Landing site in Uganda

Lake Victoria is an important source of livelihood that is threatened by rising pollution. In this study, pollutants in runoff are characterized and their dispersion after they enter the lake is measured and modeled at different points in the study areas. The objective is to develop a one dimensional mathematical model which can be used to predict the nutrient (ammonia, nitrite, nitrate, and phosphate) dispersion distances within the lake. A comparison between rain period nutrient concentrations and dry period nutrient concentrations within the Lake showed an elevation in nutrient levels during the rainy season, with exception of nitrate. However, nitrate had high levels during the dry season. Ammonia was found to disperse to horizontal distances of 38 m; nitrite 45 m, with nitrate and phosphate each attaining distances of 34 m. Measured nutrient concentration within the Lake compared well with model estimations.Key words: Modeling, water quality, nutrients, lake Victoria

Estimating runoff from ungauged catchments for reservoir water balance in the Lower Middle Zambezi Basin

The Lower Middle Zambezi Basin is sandwiched between three hydropower dams; Kariba, Kafue (Itezhi-tezhi) and Cahora Bassa. The operation of the upstream dams impacts on the inflows into the downstream Cahora Bassa Dam which, in turn, affects the area inundated upstream of the Cahora Bassa Dam. This study applied a rainfall-runoff model (HEC-HMS) and GIS techniques to estimate both the gauged and ungauged runoff contribution to the water balance of Cahora Bassa. The rivers considered in the study are the Zambezi, Kafue, Luangwa, Chongwe, Musengezi and Manyame. Missing data were generated using the mean value infilling method. The DEM hydro-processing technique was used to determine the spatial extent of the ungauged area. A hydrological model, HEC- HMS, was used to simulate runoff from the ungauged catchments. Results from the study show that the ungauged catchment contributes about 12% of the total estimated inflows into the Cahora Bassa Dam. Averaged results over 30 years show total inflows of 71.73 x 109 m3/yr, total outflows of 52.25 x 109 m3/ yr and a residual storage of 20 x 109 m3/yr. The study successfully estimated the water balance of the Middle Zambezi Basin which, in turn, may help to inform the operation of the Cahora Bassa Dam and management of artificial floods in the basin.Keywords: Cahora Bassa, DEM hydroprocessing, HEC-HMS, remote sensing, reservoir operation, runoff simulatio

Wastewater management in Zimbabwe

Wastewater management in Zimbabw