Heavy metals and metalloids concentrations across UK urban horticultural soils and the factors influencing their bioavailability to food crops

Urban horticulture (UH) has been proposed as a solution to increase urban sustainability, but the potential risks to human health due to potentially elevated soil heavy metals and metalloids (HM) concentrations represent a major constraint for UH expansion. Here we provide the first UK-wide assessment of soil HM concentrations (total and bioavailable) in UH soils and the factors influencing their bioavailability to crops. Soils from 200 allotments across ten cities in the UK were collected and analysed for HM concentrations, black carbon (BC) and organic carbon (OC) concentrations, pH and texture. We found that although HM are widespread across UK UH soils, most concentrations fell below the respective UK soil screening values (C4SLs): 99 % Cr; 98 % As, Cd, Ni; 95 % Cu; 52 % Zn. However, 83 % of Pb concentrations exceeded C4SL, but only 3.5 % were above Pb national background concentration of 820 mg kg−1. The bioavailable HM concentrations represent a small fraction (0.01–1.8 %) of the total concentrations even for those soils that exceeded C4SLs. There was a significant positive relationship between both total and bioavailable HM and soil BC and OC concentrations. This suggest that while contributing to the accumulation of HM concentrations in UH soils, BC and OC may also provide a biding surface for the bioavailable HM concentrations contributing to their immobilisation. These findings have implications for both management of the risk to human health associated with UH growing in urban soils and with management of UH soil. There is a clear need to understand the mechanisms driving soil-to-crop HM transfer in UH to improve potentially restrictive C4SL (e.g. Pb) especially as public demand for UH land is growing. In addition, the UH community would benefit from education programs promoting soil management practices that reduce the risk of HM exposure - particularly in those plots where C4SLs were exceeded

Knowledge management in the context of sustainability: Literature review and opportunities for future research

© 2019 The use of knowledge management in the context of sustainability has been increasingly important over the years. Despite this importance, it is observed that this area is still little explored and there are many possibilities of academic research. Following a structured research protocol, the authors of this article performed a systematic review of the literature and identified plausible gaps to be explored in the development of future research. These gaps are presented in relation to the themes, strategies, objectives and research approach. From the point of view of the themes, there are opportunities related to the study of sustainability in small and medium enterprises, in relation to the potential of universities as engines for the generation of knowledge and in concerning the insertion of knowledge management to propose guidelines for obtaining productive systems. Regarding research strategies, the lack of studies that use action research as central focus stands out. Focusing on the objectives, there are many research approaches used with the goal of developing models and specific tools directed to the sharing of information. Finally, regarding the approach, there are few studies with a quantitative approach. We believe that the information presented here can contribute to the evolution of knowledge management focused on sustainability. No similar studies were found in the literature