Abstract: Delonix regia, an ornamental tree that can tolerate an elevated level of heavy metals, was evaluated for phytoremediation potential in mine tailings with fly ash, compost, and mycorrhiza. A two-factorial experiment was conducted under screen house conditions using mine tailings from Bamangwato Concessions Limited (BCL) Cu-Ni mine. The treatments are mine tailing (MT) without mycorrhiza (MT – AM), MT with mycorrhiza (MT + AM), MT with 10% fly ash (FA) without mycorrhiza (MT + FA �...
Abstract: Droughts pose a significant challenge to water resources, causing several socio-economic consequences. The growing economy requires improved assessments of drought-related impacts in the water sector, particularly under semi-arid environments where its climate is getting drier and warmer. This study proposes a probabilistic model (copula approach) that is intended to contribute to the drought risk assessment by providing an essential information in drought prediction, decision...
Abstract: Global insect pest invasions have dramatically increased over the past decades, posing significant biosecurity threats to natural and managed ecosystems. As such, the mechanisms of spread and rapid establishment of invasive species have been a key issue for agricultural stakeholders. Similarly, while availability of suitable plant hosts is key to establishment, the eco-physiological mechanisms facilitating invasion amongst most invasive species are unclear. The South American ...
Abstract: Human exposure to Naturally Occurring Radioactive Materials (NORMs) and toxic heavy metals has been a concern for the entire history of mankind since they are com monly found in the environment. Their increased levels are a result of anthropogenic activities such as mining. A-cap Resources Ltd, now A-cap Energy Ltd company dis covered that there were large uranium deposits in the underlying rocks of Serule. It was given licensing to start mining in 2016 with a lease of about 144 km...
Abstract: Shooting ranges continue to pose environmental and human health risk due to the accumulation of toxic Pb emanating from munitions. Remediation of Pb pollution at shooting ranges has been carried out through application of various techniques of which chemical stabilization is the most common. In some instances, field chemical stabilization has achieved Pb decontamination of the soils to concentrations below the maximum contaminant limits as set by the United States Environmental Pro...
Abstract: Bacterial diversity is known to be a driver of soil ecosystem services and it is influenced by the natural integrity of the environments. Samples from garden soil, saline soil and sludge-impacted soil were studied to evaluate the influence of soil properties on bacterial abundance and diversity for improved management. Soil samples were collected from 0 to 15 cm depth and analyzed for selected physico-chemical properties using routine labo- ratory procedures. 16S rRNA gene-based me...
Abstract: Commissioned and de-commissioned shooting ranges continue to pose an environmental and human health risk due to the accumulation of toxic Pb emanating from spent munitions. The phytotoxic effects of Pb accumulation in plants include inhibition of root growth and lowering of plant metabolism. The uptake of Pb by plants is directly affected by factors such as plant species and physicochemical properties of the soil. However, scientists and researchers have leveraged on the ability of...
Abstract: Distributed numerical models, considered as optimal tools for groundwater resources management, have always been constrained by availability of spatio-temporal input data. This problem is particularly distinct in arid and semi-arid developing countries, characterized by large spatio-temporal variability of water fluxes but scarce ground-based monitoring networks. That problem can be mitigated by remote sensing (RS) methods, which nowadays are applicable for modelling not only surfa...
Abstract: Composting is a common method of household waste in developing countries such as Botswana. However, compost can introduce heavy metals which are harmful to the environment. High concentrations of heavy metals are toxic to plants and humans and can affect soil by killing soil microorganisms. The aim of this study was to investigate the amount of four heavy metals (Cr, Co, Cu and Pb) in Gamodubu soils that are associated with leachate from a landfill in that area. Soil samples were c...
Abstract: The industrial effluents contain substantial amounts of toxic heavy metal ions which pollutes surface water and groundwater. In this study, the adsorptive removal of copper, iron and nickel ions from wastewater using Makoro Granite brick waste (MGBW), Makoro Gold Satin (MGS) clay brick waste, copper smelter slag (CSS) and cement brick waste (CBW) as novel adsorbents has been investigated at batch mode. The mineralogical and chemical content of adsorbents was determined using X-...
Abstract: There has been a decline in groundwater quality in most wellfields in Botswana. This study evaluated the groundwater quality in Dukwi Wellfield for drinking and irrigation purposes and characterised the dominant hydrochemical processes in the wellfield area during winter and summer seasons. The parameters used to assess the water quality for irrigation purposes were percent sodium (%Na) and Sodium Adsorption Ratio (SAR), while for drinking purposes, Water Quality Index (WQI) was as...
Abstract: The rapid population growth and industrialisation has contributed to the production of large quantities of solid wastes that should be managed properly. This study was conducted to investigate the generation and composition of solid wastes at different income levels during weekdays and weekends in a particular zone in Palapye municipality (Extension 7), Botswana. The study was conducted through sampling of wastes at source and analysis at the laboratory. In increasing order, the ge...
Abstract: Bush encroachment of savannah ecosystems in countries like Botswana and Namibia has been identified as a major problem threatening biodiversity, grazing land productivity and the generation of groundwater. Incidentally, the same problem presents a huge biomass energy resource opportunity which can be exploited through various technologies. This paper defines the scope of the problem in Botswana, comparing with the well documented and partly proven case of encroacher bush waste valo...
Abstract: Over the years, the world was not paying strict attention to the impact of rapid growth in plastic use. This has led to unprecedented amounts of mixed types of plastic waste entering the environment unmanaged. Packaging plastics account for half of the global total plastic waste. This paper seeks to give an overview of the use, disposal, and regulation of food packaging plastics. Demand for food packaging is on the rise as a result of increasing global demand for food due to popula...
Abstract: Reconstructions of climatic and environmental conditions can contribute to current debates about the factors that influenced early human dispersal within and beyond Africa. Here we analyse a 200,000-year multi-proxy paleoclimate record from Chew Bahir, a tectonic lake basin in the southern Ethiopian rift. Our record reveals two modes of climate change, both associated temporally and regionally with a specific type of human behavior. The first is a long-term trend towards greater ar...