Search Results (10)

This study investigates the effect of high urban land temperatures on pesticide residue (PR) accumulation in cabbage and lettuce and on public health in the Greater Accra Metropolitan Area (GAMA) in Ghana. A comparative toxicological analysis regarding the food system was conducted with 66 farmers across three land surface temperatures: low (Atomic, n = 22), moderate (Ashaiman, n = 22), and high (Korle-Bu, n = 22). Pesticide residue concentrations were assessed using an ANOVA to examine spatial variations across sites. The results indicate a strong correlation between high land surface temperatures and pesticide residue accumulation, with lettuce recording significantly (p < 0.05) higher PR levels than cabbage. Several pesticides, including carbendazim (CBZ), Imidacloprid (IMI), Thiamethoxam (TMX), and Chlorpyrifos (CHL), exceeded the maximum residue limits (MRLs) set by the World Health Organization (WHO) and the European Union (EU) at moderate and high-temperature sites. carbendazim was the dominant pesticide detected, with a concentration of 19.0 mg/kg in lettuce, which far exceeded its maximum residue limit (MRL) of 0.10 mg/kg across all study sites. Statistical analyses (PERMANOVA) confirmed that land surface temperatures and pesticide types significantly influenced the PR concentrations. Public health risk assessments indicate that children are more vulnerable to pesticide exposure than adults. The toxicity hazard quotient (THQ) for organophosphate pesticides, particularly CHL and Dimethoate (DMT), exceeded safe thresholds at moderate and high-temperature sites. Full article

Urbanization and population growth in West Africa have significantly altered land use and land cover (LULC), raising environmental concerns. This study examines urban land use patterns in the District Autonome du Grand Lomé (DAGL) and Greater Accra Metropolitan Area (GAMA) from 1986 to 2023 and from 1991 to 2023, respectively, using geospatial techniques and the Google Earth Engine (GEE). Previous research has overlooked the complexity of land use patterns and the directional analysis of urban expansion, which are vital for understanding urbanization drivers. This study addresses these gaps by comparing the two metropolitan areas, revealing a dramatic decline in verdant landscapes, with forested areas in DAGL decreasing from 24% in 1986 to 3% by 2023, and from 34% in 1991 to 2% in GAMA. Grasslands also diminished significantly, while built-up areas expanded from 18% to 62% in DAGL and from 10% to 70% in GAMA. The Urban Expansion Intensity Index (UEII) indicates rapid urban growth, with DAGL at 1.19% and GAMA at 1.88%. Directional analyses reveal that urban expansion predominantly occurs toward the northwest in DAGL and both northeast and northwest in GAMA, highlighting the need for effective urban planning and land management to preserve natural landscapes amidst ongoing urbanization challenges. Full article

Information about flood-prone areas in Accra, Ghana, acting as obstacles to the main infrastructure was required as input for a transportation study. We successfully identified these areas using the hydrologic screening software Arc-Malstrøm. Earlier studies have used a digital elevation model with a spatial resolution of 30 m, which unfortunately is not a true digital terrain model as it includes elevations from ground surfaces, structures, and vegetation. However, this study shows the benefits of using a hydro-conditioned 10 m resolution digital terrain model from Airbus^TM in predicting flood-prone areas. The entire investigation area covers approximately 23% of the Greater Accra Metropolitan Area (GAMA), including the entire Odaw River basin. In this area, 5018 landscape sinks with water depths ≥ 0.1 m and volumes ≥ 5 m³ were identified. From this, 163 flood-induced roadblocks were found with maximum depths ≥ 0.3 m, rendering them impassable to normal vehicles. Beyond the adaptation of infrastructures in the hydro-conditioning process, more steps were necessary along the Odaw River’s southernmost course before its outlet into the Gulf of Guinea due to local trash accumulation reflected in the DTM. To address the unforeseen stochastic flood effects from trash piling up along the river channels, a simulation was conducted showing the upstream consequences caused by a trash barrier at the river’s outlet into the ocean. This leads to a discussion of the hazards posed by improper waste handling, coupled with increasing runoff predictions within the river’s drainage basin. Finally, we discuss local alternatives to the establishment of large central retention and detention basins to reduce flood-prone areas in GAMA during periods when stormwater-induced floods become more frequent, primarily due to uncontrolled urbanization increasing runoff volumes. Full article

Cities in developing countries continue to struggle with mounting waste management challenges. Within a circular economy framework, energy recovery is mostly nonexistent. Against that background, this study aimed to design and assess the viability of a hybrid waste-to-energy facility for the Greater Accra Metropolitan Area (GAMA) in Ghana by 2030. The proposed plant integrates solar PV, anaerobic digestion and pyrolysis to treat unsegregated municipal solid waste. Three cases were developed for different product combinations. Material flow analysis was performed with STAN software 2.7.101. The results indicate that 1.6 million tons of MSW will be generated, to be potentially converted to 271 GWh of electricity, 6400 tons of hydrogen or 4400 tons of bio-compressed natural gas per year, along with additional products: compost, refuse-derived fuel and bio-oil. The economic indicators show that all cases are potentially viable in terms of the net present value (EUR 397 to 1030 million), internal rate of return (14–22%) and levelized cost of energy (0.11–0.18 EUR/kWh). As such, this study proves that waste to energy is a viable waste management solution for large metropolitan areas, with the potential to supply energy, alternative fuels and material products within a circular economy, though it requires the buy-in of policy makers. Full article

Dust levels around the Tema industrial area of the Greater Accra Region have seen no reduction in recent years. Even though at some periods in time a natural drop in dust pollution levels is assured, the overall variation characteristics of the concentration of PM_2.5, PM₁₀, and Total Suspended Particles (TSP) have not been studied in recent years. This paper examines the levels of dust pollution across four (4) locations within the Tema metropolitan area with a specific interest in selecting locations and periods (weeks) significantly affected by dust pollution within the study area. Data collection was done over a nine-month period using the Casella 712 Microdust Pro Kit equipment. Measurements were done day and night at sampling points about 100 m apart in a given location. Monitoring was conducted once a week during the day and at night with a sampling period of 24 h per location, for thirty-six weeks. The generalized linear models were explored in selecting locations and weeks significantly affected by dust pollution. The study results showed no significant difference between pollution levels across the four selected locations. Eight, eleven, and five weeks out of the 36 weeks recorded significantly high concentrations of PM_2.5, PM₁₀, and TSP respectively. In addition, two out of the selected four areas (the oil jetty area and the VALCO hospital area) were found to have significantly high concentrations of dust pollution. The study recommends that an urgent air quality control policy intervention be put in place to control the highly alarming levels of dust pollution concentrations to guarantee and protect human health within the study area and beyond. Full article

Intensive land-cover changes (LCC) driven by unplanned urbanisation continue to threaten the sustainability of ecological assets in many cities in Africa. Evaluating the nature and processes of these changes is key to understanding the extent to which ecological instability may be affecting sustainability futures. This study employed integrated remote sensing, GIS, land accounting techniques and utilisation of high-resolution Quickbird and Worldview 2 images to analyse actual (2008–2017) and future (2017–2030) LCC and explored implications for ecological sustainability in the Greater Accra Metropolitan Area, Ghana. After mapping and classifying actual LCC, multi-layer perception (MLP) neural network and Markov chain were employed to predict future LCC for the year 2030. The results indicate that the built-up area increased substantially from 27% in 2008 to 46% in 2017 and is expected to rise to 73% by 2030. In contrast, open-space (10%), forestlands (5%) and grassland/farmlands (49%) decreased progressively (2008–2030). In effect, these land-cover types experienced area turnover ˃100% during the actual and predicted period, indicating high vulnerability of natural land cover to urban growth, ecological degradation and resource depletion. These findings highlight significant implications of LCC for ecological sustainability in the study area. A proactive land-cover/use management plan is necessary to ensure sustainable urban development and ecological land conservation. Full article

This study analyzed and assessed spatio-temporal dynamics of land-use change (LUC) and urban expansion (UE) within the Greater Accra Metropolitan Area (GAMA) of Ghana. This region serves as a case to illustrate how a major economic hub and political core area is experiencing massive spatial transformations, resulting in uneven geographies of urban land expansion. Quickbird/Worldview-2 images for the years 2008 and 2017 were segmented and classified to produce LUC maps. LUC and UE were analyzed by post-classification change detection and spatial metrics, respectively. The results revealed an intensive decrease in open-space by 83.46 km², brushland/farmland (194.29 km²) and waterbody/wetland (3.32 km²). Conversely, forestland and urban built-up area increased by 3.45 km² and 277.62 km². Urban extent expanded from 411.45 km² (27%) in 2008 to 689.07 km² (46%) in 2017 at a rate of 5.9% and an intensity of 2.06% with an expansion coefficient of 1.5%, indicating low-density urban sprawl. The spatial pattern turned out to be an uneven and spatially differentiated outward expansion, which materialized mainly in districts located within the urban peripheries but intensely towards eastern and western directions, being the frontier and the hotspots of urbanization. Overall, the findings bear important implications for regional spatial planning and development. Full article

A rapid increase in the world’s population over the last century has triggered the transformation of the earth surface, especially in urban areas, where more than half of the global population live. Ghana is no exception and a high population growth rate, coupled with economic development over the last three decades, has transformed the Greater Accra region into a hotspot for massive urban growth. The urban extent of the region has expanded extensively, mainly at the expense of the vegetative cover in the region. Although urbanization presents several opportunities, the environmental and social problems cannot be underestimated. Therefore, the need to estimate the rate and extent of land use/land cover changes in the region and the main drivers of these changes is imperative. Geographic Information Systems (GIS) and remote sensing techniques provide effective tools in studying and monitoring land-use/land-cover change over space and time. A post classification change detection of multiple Landsat images was conducted to map and analyse the extent and rate of land use/land cover change in the region between 1991 and 2015. Subsequently, the urban extent of the region was forecasted for the year 2025 using the Markov Chain and the Multi-Layer Perceptron neural network, together with drivers representing proximity, biophysical, and socio-economic variables. The results from the research revealed that built-up areas increased by 277% over the 24-year study period. However, forest areas experienced massive reduction, diminishing from 34% in 1991 to 6.5% in 2015. The 2025 projected land use map revealed that the urban extent will massively increase to cover 70% of the study area, as compared to 44% in 2015. The urban extent is also anticipated to spill into the adjoining districts mainly on the western and eastern sides of the region. The success of this research in generating a future land-use map for 2025, together with the other significant findings, demonstrates the usefulness of spatial models as tools for sustainable city planning and environmental management, especially for urban planners in developing countries. Full article

Improvements in water, sanitation and hygiene (WASH) service provision are hampered by limited open data availability. This paper presents a data integration framework, collects the data and develops a material flow model, which aids data-based policy and infrastructure development for the WASH sector. This model provides a robust quantitative mapping of the complete anthropogenic WASH flow-cycle: from raw water intake to water use, wastewater and excreta generation, discharge and treatment. This approach integrates various available sources using a process-chain bottom-up engineering approach to improve the quality of WASH planning. The data integration framework and the modelling methodology are applied to the Greater Accra Metropolitan Area (GAMA), Ghana. The highest level of understanding of the GAMA WASH sector is achieved, promoting scenario testing for future WASH developments. The results show 96% of the population had access to improved safe water in 2010 if sachet and bottled water was included, but only 67% if excluded. Additionally, 66% of 338,000 m³ per day of generated wastewater is unsafely disposed locally, with 23% entering open drains, and 11% sewage pipes, indicating poor sanitation coverage. Total treated wastewater is <0.5% in 2014, with only 18% of 43,000 m³ per day treatment capacity operational. The combined data sets are made available to support research and sustainable development activities. Full article

This paper reports the findings of a qualitative study investigating the impacts of renting a home on the psychosocial health of tenants in the Accra Metropolitan Area (AMA) in Ghana. In-depth interviews (n = 33) were conducted with private renters in Adabraka, Accra. The findings show that private renters in the AMA face serious problems in finding appropriate and affordable rental units, as well as a persistent threat of eviction by homeowners. These challenges tend to predispose renters to psychosocial distress and diminishing ontological security. Findings are relevant to a range of pluralistic policy options that emphasize both formal and informal housing provision, together with the reorganization and decentralization of the Rent Control Board to the district level to facilitate easy access by the citizenry. Full article