Safety of food crops on land contaminated with trace elements

Contamination of agricultural soils with trace elements (TEs) through municipal and industrial wastes, atmospheric deposition and fertilisers is a matter of great global concern. Since TE accumulation in edible plant parts depends on soil characteristics, plant genotype and agricultural practices, those soil- and plant-specific options that restrict the entry of harmful TEs into the food chain to protect human and animal health are reviewed. Soil options such as in situ stabilisation of TEs in soils, changes in physicochemical parameters, fertiliser management, element interactions and agronomic practices reduce TE uptake by food crops. Furthermore, phytoremediation and solubilisation as alternative techniques to reduce TE concentrations in soils are also discussed. Among plant options, selection of species and cultivars, metabolic processes and microbial transformations in the rhizosphere can potentially affect TE uptake and distribution in plants. For this purpose, genetic variations are exploited to select cultivars with low uptake potential, especially low-cadmium accumulator wheat and rice cultivars. The microbial reduction of elements and transformations in the rhizosphere are other key players in the cycling of TEs that may offer the basis for a wide range of innovative biotechnological processes. It is thus concluded that appropriate combination of soil- and plant-specific options can minimise TE transfer to the food chain

15 - E-waste recycling slum in the heart of Accra, Ghana: the dirty secrets

This chapter unpacks reasons underpinning constant contestations for space in Agbogbloshie, an urban area in Ghana’s capital Accra, housing a vegetable market, a scrap metal yard, a vast slum, an industrial area, and a household waste dump. The city authorities, with tacit support from the traditional authorities and some media outlets, employ discursive practices and documentaries to sensationalize the settlement, thereby masking its economic potentials and bringing it into direct conflict with local livelihoods. Bringing Lefebvre’s “right to the city” thesis into conversation with contemporary entrepreneurial urbanism illuminates the authorities’ deviation from its historical focus on all-inclusive development, though they continue to make loud pronouncements in local and international fora. Drawing on Lefebvre’s foundational concept of “lived space,” we demonstrate how the contours of urban place-making are more complex than generally appreciated. Our focus on residents’ place-making and their informal space economy uncover the prospects for rethinking informal urban settlements. By capturing the messy, dynamic, and contextualized processes that give life to informal settlements as places, we suggest reimagining informal settlements to better achieve their real contributions to the city economy as a whole