Closing Blank Spots and Illuminating Blind Spots in Research on Emerging Contaminants: The Source–Pathway–Receptor–Impact–Mitigation (SPRIM) Continuum as an Organizing Framework

Emerging contaminants (ECs) include: (1) high-technology rare earth elements, (2) nanomaterials, (3) antibiotic/antimicrobial resistance, (4) microplastics, and (5) synthetic organic chemicals, which are currently unregulated. ECs continue to attract considerable research and public attention due to their potential human and ecological health risks. However, an organizing conceptual framework for framing research on ECs is currently missing. Lacking a conceptual framework, only a few aspects are frequently well-studied (i.e., bandwagon/Matthew effect), while other equally important topics receive only cursory attention. In this Editorial perspective, the Source–Pathway–Receptor–Impact–Mitigation (SPRIM) continuum is proposed as an organizing framework to guide research on ECs. First, a description of the SPRIM continuum and its components is presented. Compared to the prevailing and seemingly ad hoc approach predominant in research on emerging contaminants, the potential novelty of applying the proposed SPRIM continuum framework is that it addresses the bandwagon, or Matthew, effect. As a decision-support tool, the SPRIM continuum framework serves a dual function as (1) a checklist to identify key knowledge gaps and frame future research, and (2) a primer for promoting the collaborative research and application of emerging big data analytics in research on emerging contaminants. Collectively, it is envisaged that the SPRIM continuum framework will provide a comprehensive and balanced understanding of various aspects of emerging contaminants relative to the current approach. The challenges of the SPRIM continuum framework as a framing and decision-support tool are also discussed. Future research directions on ECs are discussed in light of the SPRIM continuum concept. This Editorial closes with concluding remarks and a look ahead. The issues discussed are cross-cutting or generic, and thus relate to several groups of ECs, including emerging organic contaminants (EOCs), which are the focus of the current Special Issue. This Special Issue, entitled ‘Emerging Organic Contaminants in Aquatic Systems: A Focus on the Source–Pathway–Receptor–Impact–Mitigation Continuum’, calls for high-quality contributions addressing several aspects of EOCs in aquatic systems. As a Guest Editor, I welcome and look forward to several high-quality contributions addressing at least one component or the entire spectrum of the SPRIM continuum

Household Disposal of Pharmaceuticals in Low-Income Settings: Practices, Health Hazards, and Research Needs

Pharmaceuticals are widely used in Africa due to the high burden of human and animal diseases. However, a review of the current practices and pollution risks arising from the disposal of pharmaceuticals in low-income settings in Africa is still lacking. Therefore, the present review examined the literature to address the following questions: (1) what are the key factors driving the accumulation of unused and expired pharmaceuticals?, (2) what are the current disposal practices for unused and expired pharmaceuticals, and wastewater (feces and urine) containing excreted pharmaceuticals?, (3) what are the potential environmental and human health hazards posed by current disposal practices?, and (4) what are the key research needs on the disposal of pharmaceuticals in low-income settings? Evidence shows that, in low-income settings, wastewater comprising predominantly of feces and urine containing excreted pharmaceuticals often end up in on-site sanitation systems such as pit latrines, septic tanks, and the environment in the case of open defecation. Unused and expired pharmaceuticals are disposed of in pit latrines, household solid waste, and/or burned. The pollution risks of current disposal practices are poorly understood, but pharmaceutical pollution of groundwater sources, including those used for drinking water supply, may occur via strong hydrological connectivity between pit latrines and groundwater systems. Potential high-risk pollution and human exposure hotspots are discussed. However, compared to other environmental compartments, the occurrence, dissemination, fate, and human health risks of pharmaceuticals in the pit latrine-groundwater continuum are still understudied. Future research directions are discussed to address these gaps using the Source-Pathway-Receptor-Impact-Mitigation (SPRIM) continuum as an organizing framework

Mapping Suitable Sites for Setting up Wind Farms: A Case Study of Nyanga District

Due to the negative impacts on the environment of traditional power-generating methods, especially fossil fuels, wind power has increased in popularity. Achieving carbon emissions reduction goals due to the implementation of the Kyoto Protocol require exploitation of renewable energy, Cleaner Development Mechanisms, (CDM). Additionally, the increased difficulty of obtaining oil from foreign sources and continuous power shortages make wind energy a very attractive alternative to keep Zimbabwe powered, clean and green. In order to tap the potential of wind energy sources, there is a need to assess the spatial availability of the resources. Mapping suitable sites for setting up wind farms was the focus of this study. The study employed the Geographical Information Systems (GIS) approach to map the wind energy resources of Nyanga district and carry out a multi-criteria evaluation analysis of their potential by considering other data sets such as land cover, land use and proximity to roads. From the analysis carried out, the mean area size of the most suitable land parcels was 36.810 km2,which is therefore more than enough for a large wind farm given that an area size of 2 km2 is enough to justify the development of a 10MW wind farm project. Most suitable areas were found where commercial activities are while small patches averaging 5 to 10 km2 in rural areas make the medium suitability areas.Key Words: Mapping, Sites, Wind farm, Energy, Multi-criteria, Evaluatio

Shear strength enhancement by Digitaria setivalva associated with NPK and bio green application on Bungor soil slope

Understanding the chemical constraints to plant growth and their amelioration is critical for erosion control and slope stability on artificial landforms. Limited studies have investigated the effects of chemical amendments on grass growth, and effects on soil physical and chemical characteristics on the slope surface. Digitaria setivalva (Mardi Digit grass) was used as a grass coverage to control erosion on the steep man made slope. The current slope studies (45o-50o) on Bungor soil series to address two objectives; (1) to investigate the effects nitrogen (N)-phosphate (P)-potassium fertilizer (NPK) and Bio Green fertilizer (BG) on above-ground and root growth, and (2) to determine physico-chemical properties and root shear strength after application of treatments. The Bungor series was acidic pH (4.63), moderate soil organic carbon (1.42%), total N (0.12%),available P (12.2 mg kg-1) and potassium (0.44 mg kg-1), indicating low inherent infertility and chemical constraints to plant growth. Therefore, above-ground biomass (kg m-3) for nutrient and organic amendments; NPK+BG (7.2), BG (6.1) > NPK (2.2)was more than double that of the unamended control (1.3). A similar trend was observed for root biomass density (kg m-3);NPK+BG (272.94), BG (262.70)>NPK (133.76) > control (98.60) and root length density (cm m-3); NPK+BG (8332.0), BG(8092.0) > NPK (5200.0) > control (4000.0). Rapid vegetation growth observed within a 6-month period demonstrates that NPK and Bio Green application effectively ameliorated chemical constraints to plant growth. Enhanced vegetation growth subsequently reduced soil leachates (N, P and K) from the slope significantly as compared to NPK and Control treatments. The application of NPK+BG and BG fertilizer showed significant effect in reducing nutrients loss, increased soil aggregate stability, water retention, hydraulic conductivity and improved macro- and micro nutrients content. Enhanced vegetation growth subsequently increased shear strength (s) as evidenced by positive power relationships (r2 = 0.53-0.69, p<0.05) between root density, and angle of internal friction (ᴓ) and shear strength. The significant root-ᴓ relationship indicates that root enhanced shear strength by increasing the frictional component but not cohesion. The increase in shear strength was attributed to increase in virtual density and reduced pore water pressure attributed to root water uptake associated with rapid vegetation growth. Root biomass and root length density may increase the shear strength and reduced pore water pressure attributed to root water uptake associated with rapid vegetation growth. Under field conditions, a dense canopy and root network also reduces soil detachment and transport by raindrop impact and runoff. These multiple vegetation-soil interactions are critical for erosion control and slope stability on artificial land forms such as cut slopes

Determinants of Output Market Participation by Smallholder Farmers in Upper Guruve District, Zimbabwe

Market participation by smallholder farmers in Sub-Saharan Africa is characteristically low, with most of these farmers having limited access to both input and output markets. This paper investigates the factors associated with output market participation by smallholder farmers in Upper Guruve District, Zimbabwe. A multi-stage sampling technique was used to select 200 households for the survey, with the collected primary data analyzed using STATA version 15 through a Multinomial Logistic regression model. The key determinants to output market participation included gender, age and experience, area cropped to soyabean, input and output market prices, profitability and access to market and extension support services. The study demonstrates the need for market information dissemination so as to promote and increase soyabean productivity. Government intervention should also focus on providing an enabling environment for improved private sector involvement and gender empowerment since women are currently marginalized in soyabean production and market participation. This paper is critical for guiding policy-making and development of strategies to increase soya production for the benefit of both farmers and the economy in general. Keywords: Soyabean, Output Market Participation, Smallholder Farmers, Zimbabwe DOI: 10.7176/JESD/12-2-02 Publication date: January 31st 202

Fe0/H2O Filtration Systems for Decentralized Safe Drinking Water: Where to from Here?

Inadequate access to safe drinking water is one of the most pervasive problems currently afflicting the developing world. Scientists and engineers are called to present affordable but efficient solutions, particularly applicable to small communities. Filtration systems based on metallic iron (Fe0) are discussed in the literature as one such viable solution, whether as a stand-alone system or as a complement to slow sand filters (SSFs). Fe0 filters can also be improved by incorporating biochar to form Fe0-biochar filtration systems with potentially higher contaminant removal efficiencies than those based on Fe0 or biochar alone. These three low-cost and chemical-free systems (Fe0, biochar, SSFs) have the potential to provide universal access to safe drinking water. However, a well-structured systematic research is needed to design robust and efficient water treatment systems based on these affordable filter materials. This communication highlights the technology being developed to use Fe0-based systems for decentralized safe drinking water provision. Future research directions for the design of the next generation Fe0-based systems are highlighted. It is shown that Fe0 enhances the efficiency of SSFs, while biochar has the potential to alleviate the loss of porosity and uncertainties arising from the non-linear kinetics of iron corrosion. Fe0-based systems are an affordable and applicable technology for small communities in low-income countries, which could contribute to attaining self-reliance in clean water supply and universal public health

Partitioning of turbulent flux reveals contrasting cooling potential for woody vegetation and grassland during heat waves

© 2015 Royal Meteorological Society. We compared the capacity of woody versus grassy vegetation covers to buffer high temperatures during heat waves by partitioning turbulent heat between latent (λE) and sensible (H) fluxes, and quantifying advection using the Priestley-Taylor coefficient (α), for a16-year old grassland and an adjoining 6-year old plantation. We found that because λE dominated (>65%) the turbulent flux in the plantation and was at least twice as large as on the grassland (λE35°). Annual evapotranspiration was 54% lower from the grassland (384 mm) than from the plantation (834 mm). Woody vegetation covers dominated by broadleaved species are therefore preferred for buffering extreme high temperatures during heat waves and recommended for rehabilitating degraded landscapes in urban areas. We also present functions for approximating α for soil water limited conditions

Visible light photodegradation of methyl orange and Escherichia coli O157:H7 in wastewater

Water pollution due to dyes and pathogens is problematic worldwide, and the disease burden is higher in low-income countries where water treatment facilities are usually inadequate. Thus the development of low-cost techniques for the removal of dyes and pathogens in aquatic systems is critical for safeguarding human and ecological health. In this work, we report the fabrication and use of a photocatalyst derived from waste from coal combustion in removing dyes and pathogens from wastewater. Higher TiO2 loading of the photocatalyst increased the removal efficiency for methyl orange (95.5%), and fluorine-doping improved the disinfection efficacy from 76% to 95% relative to unmodified material. Overall, the work effectively converted hazardous waste into a value-added product that has potential in point-of-use water treatment. Future research should focus on upscaling the technique, investigating the fate of the potential of the photocatalysts for multiple reuse, and the recovery of TiO2 in treated water. Significance: • The study provides a pathway for the fabrication of a value-added product from coal fly ash waste.• The use of the proposed nanocomposite material for wastewater treatment represents a potentially affordable, simple, and sustainable technology for point-of-use water treatmen

Circular bioeconomy potential and challenges within an African context: From theory to practice

A circular bioeconomy has the potential to minimize the environmental impacts of biowaste while simultaneously generating value-added bioproducts and bioenergy. Currently, most countries of the African Union lack well-defined policies, requisite infrastructure, and expertise for biowaste valorisation, thus limiting the potential development of the region. Against this background, it is necessary to deploy circular bioeconomy principles based on the awareness of the biocapacity of territories through the nexus of biowaste management and life cycle thinking. In the present study, a preliminary assessment of waste management practices in a tourist hotel in Victoria Falls in Zimbabwe is explored. The hotel produces about 3.26 tons per month of biowaste, which is often improperly disposed in non-engineered waste dumps. Furthermore, the disposal options for 1 tonne of biowaste are explored using City of Harare (CoH) as a case study. The preliminary results show composting as the most environmentally favourable option (9.6 kg CO2 eq), followed by anaerobic digestion (56.4 kg CO2 eq), and finally, biowaste incineration (140 kg CO2 eq). Anaerobic digestion and composting remain the most viable biowaste disposal alternatives in Africa, due to limited expenses and expertise for construction, operation, and maintenance. However, both technologies remain under-utilized, hence, a significant portion of the source-separated biowaste is still disposed of in waste dumps and this reflects the lack of supportive institutional, regulatory and policy frameworks. Overall, these early results point to the potential to develop a circular bioeconomy in Africa, while calling for shared responsibilities among the state, market, and civil society actors to develop and adopt appropriate institutional, regulatory, policy and funding models