Evaluating contamination exposure rates in different Urban Agriculture (UA) practices

Introduction: Urban Agriculture (UA) is instrumental in instilling a degree of self-sufficiency in food production inevitable for a resilient and sustainable city. Nevertheless, urban soil can be a substantial source of contamination due to previous, ongoing or even adjacent land-use like heavy traffic, and consumption of fresh produce grown on such could be an added exposure pathway for the urban population. These concerns lead many countries to follow strict regulation for gardening in urban areas bracketing it with residential use accentuating the exposure risks. But there are many UA practices with varying degree of user involvement and management; the prevalent ones taking place well-out of the residential periphery. However, there exist neither a definitive soil screening guideline that refers to such variations of UA practices nor studies on UA scenarios to modify the existing risk models.Methods: This study identifies different UA scenario and compares the contamination exposure to highlight the difference of risk in them. An exposure risk model is created combining with UA scenario sensitive parameters to test on five different practices; house garden, allotment garden, neighbourhood greenspace, meadow orchard and arable land. The scenario exposure data is to be collected from surveying different UA practice group in Gothenburg, Sweden. \ua0Results: The preliminary result with elicited data shows that practices with residential or extensive use such as house garden, neighbourhood greenspace and arable land predictably have high risk.\ua0 More common UA uses such as allotment gardens are much less risky when exposed to the same concentration of contamination while dropping to almost none for meadow orchards.Conclusion: Retrofitting abandoned, and derelict lands allow UA to find a place in the competitive urban land market. More knowledge on the exposure from soil contamination from different UA practices would provide more options to bring back obsolete land in use

Indicators for sustainability assessment of small-scale wastewater treatment plants in low and lower-middle income countries

Wastewater treatment in low and lower-middle income countries is often limited by lack of local technical\ua0expertise, institutional capacity, and financial resources, making it challenging to reach SDG6-target 6.3, i.e.\ua0halving the proportion of untreated wastewater. Several studies suggest sets of sustainability indicators for\ua0assessing the planning and/or operation of WWTPs. However, existing standard indicators are typically focused\ua0on the context of high and upper-middle income countries, whereas low and lower-middle income countries face\ua0other types of issues. The development of a contextualized set of relevant and effective sustainability indicators to\ua0support the planning and/or operation of small-scale WWTPs in low and lower-middle income countries is crucial.\ua0This study develops a contextualized set of sustainability indicators for small-scale wastewater treatment plants inBolivia, which is classified as a lower-middle income country. Indicators were identified using a literature review\ua0combined with empirical studies using focus groups with managers and operators, as well as, workshops with\ua0experts. The aim of the focus groups and workshops was to acquire an understanding of the local context and\ua0identify relevant sustainability indicators. The practical investigation took place at five sites in Cochabamba,\ua0Bolivia. The results suggest that sustainability assessment of WWTPs in low and lower-middle income countries\ua0should emphasize the institutional dimension (e.g. Institutional capacity, Interactions, and Information) and the\ua0technical dimension (e.g. Sewage network functionality and Expertise) alongside indicators in the social, economic\ua0and environmental dimensions

Transforming brownfields into urban greenspaces: A working process for stakeholder analysis

Urban greenspaces (UGS) provide a range of ecosystem services and are instrumental in ensuring the liveability of cities. Whilst incorporating UGS in increasingly denser cities is a challenge to planners, brownfields form a latent resource with the potential of being converted into UGS. Transformation of brownfields to greenspaces, however, requires engagement of a variety of stakeholders, from providers to users. The overall aim of this study was to support effective and realistic realisations of UGS in the context of urban brownfields’ regeneration and stakeholder engagement. A working process was developed to: 1) integrate methods relevant for UGS realisation for a) identification and categorising of relevant stakeholders, b) mapping their interests and resources, c) identifying various challenges, and d) matching those challenges with the mapped resources over the timeline of UGS development; and 2) apply these methods to assess relevance and shortcomings. The methods were applied to a study site in Sweden, and data was collected using a questionnaire survey. The survey received 31 responses and the respondents’ comments indicated that the combination of several uses, especially integrated with an urban park, is preferable. Visualisation was an important component for data analysis: stakeholder categorisation was effectively visualised using a Venn diagram, and the needed mobilisation of resources among stakeholders to manage identified challenges was visualised using a timeline. The analysis demonstrates the need for collaboration between stakeholders to achieve an effective realisation of UGS and how multiple methods can be used in concert to map stakeholders, preferences, challenges, and resources for a particular site. The application at a study site provided site-specific data but the developed stakeholder categorisation, and the method for matching identified challenges with the stakeholders’ resources using a timeline, can be generalised to applications at other sites

Comparison of PFAS soil remediation alternatives at a civilian airport using cost-benefit analysis

Contamination of soil and water systems by per- and polyfluoroalkyl substances (PFAS) due to uncontrolled use of aqueous film-forming foams (AFFFs) at firefighting training sites at civilian and military airports is a universal issue and can lead to significant human health and environmental impacts. Remediation of these sites is often complex but necessary to alleviate the PFAS burden and minimise the risks of exposure by eliminating the hotspot/source from which the PFAS spreads. This study presents a probabilistic cost-benefit analysis (CBA) for evaluating PFAS remediation alternatives, which includes monetisation of both direct costs and benefits as well as externalities. The method is applied for a case study to compare five remediation alternatives for managing PFAS contaminated soil at Stockholm Arlanda Airport in Sweden. The social profitability, or the net present value (NPV), of each remediation alternative was calculated in comparison to two reference alternatives – ‘total excavation’ of the site (Alt 0) or ‘do nothing’. Sensitivity analyses and model scenarios were tested to account for uncertainties, including small or large PFAS spreading and simulating different values for the magnitude of annual avoided cost of inaction (i.e., aggregate benefit) from PFAS remediation. In comparison to total excavation, four of the five studied remediation alternatives resulted in a positive mean NPV. Excavation and stabilization/solidification of the hotspot on-site combined with stabilization using activated carbon for the rest of site (Alt 2) had the highest NPV for both spreading scenarios, i.e., Alt 2 was the most socially profitable alternative. Simulations of the annual avoided cost of inaction enabled estimation of the breakeven point at which a remediation alternative becomes socially profitable (NPV > 0) compared to ‘do nothing’. Alt 2 had the lowest breakeven point: 7.5 and 5.75 millions of SEK/year for large and small spreading, respectively

EVAS - a practical tool to assess the sustainability of small wastewater treatment systems in low and lower-middle-income countries

Small wastewater treatment systems (WWTSs) in low and lower-middle income countries still face challenges to achieve optimal performance and acceptable levels of sustainability. Thus, a practical tool, easy to apply by locals, to diagnose the actual status of WWTSs is required in order to identify weak areas for further improvement. This study presents a sustainability assessment tool, EVAS (EVAluaci\uf3n de Sostenibilidad: EVAluation of Sustainability), for small WWTSs in low and lower-middle income countries. The EVAS tool is developed based on a set of contextualized sustainability indicators and sub-indicators in five dimensions (technical, environmental, social, economic, institutional). Each indicator or sub-indicator is broken down into factors, each associated with specific targets to fulfil, and scored using a traffic light scale (0 to 4) indicating unsustainable-low-medium to high levels of sustainability. The tool was developed taking into consideration that local data may sometimes be incomplete and encourages the collection and monitoring of relevant data. The assessment results support local managers or other stakeholders responsible for wastewater management with the identification of weaknesses that need to be addressed. The tool was tested using two case studies involving WWTSs in Bolivia. One WWTS received a medium sustainability rating, whereas the other system received a low sustainability rating, which indicates that several improvements are required in all sustainability dimensions. Stakeholders in the case studies found the tool useful, and suggested ways in which it could be further improved. It is expected that the application of this tool can contribute to raising the sustainability level of small WWTSs in low and lower-middle-income countries

A meta-evaluation of climate policy evaluations: findings from the freight transport sector

Knowledge about how implemented policy instruments have performed is important for designing effective and efficient policy instruments that contribute to reductions of greenhouse gas emissions. This paper carries out a meta-evaluation of ex-post evaluations of climate policy instruments in the freight transport sector. By analysing the outcomes and quality of evaluations, the aim is to identify whether estimated effects of policy instruments can be compared between evaluations and if the results are appropriate to use for evidence-based decision making. To analyse these aspects, commonly applied evaluation criteria are assessed and classified according to an assessment scale. We confirm that few ex-post evaluations are carried out and that there is a gap between evaluation theory and how ex-post policy evaluations are performed in practice, where evaluation criteria recommended in policy evaluation guidelines are found to often be neglected in evaluations. The result is a lack of systematic climate policy evaluation which hinders reliable conclusions about the effect of policy instruments. There is a need for more systematic monitoring and evaluation of implemented policy instruments and we suggest that evidence-based decision making can be improved by adjusting current policy evaluation guidelines and by introducing an evaluation obligation

A risk management framework for Gentle Remediation Options (GRO)

Gentle Remediation Options (GRO) are remediation measures involving plants, fungi, bacteria, and soil amendments that can be applied to manage risks at contaminated sites. Several studies and decision-support tools promote the wider range of benefits provided by GRO, but there is still skepticism regarding GRO implementation. Key issues that need to be better communicated are the various risk mitigation mechanisms, the required risk reduction for an envisioned land use, and the time perspective associated with the risk mitigation mechanisms. To increase the viability and acceptance of GRO, the phytomanagement approach implies the combination of GRO with beneficial green land use, gradually reducing risks and restoring ecosystem services. To strengthen the decision basis for GRO implementation in practice, this paper proposes a framework for risk management and communication of GRO applications to support phytomanagement strategies at contaminated sites. The mapping of the risk mitigation mechanisms is done by an extensive literature review and the Swedish national soil guideline value model is used to derive the most relevant human health exposure pathways and ecological risks for generic green land use scenarios. Results indicate that most of the expected risk mitigation mechanisms are supported by literature, but that knowledge gaps still exist. The framework is demonstrated to support the identification of GRO options for the case study site given two envisioned land uses: biofuel park and allotment garden. A more easily understandable risk management framework, as proposed here, is expected to act as a communication tool to educate decision-makers, regulatory bodies and other stakeholders for better understanding of risk mitigation mechanisms and preliminary timeframes of various GRO, particularly in the early stages of a brownfield redevelopment project

Enhancing ecosystem services at urban brownfield sites - What value does contaminated soil have in the built environment?

Urban environments are challenged with a plethora of wicked problems in the face of rapid urbanization and land use change, not least natural capital degradation and widespread land and water contamination. Brownfields, under-used sites with real or perceived contamination, are significant urban and peri-urban land resources which, with well-designed remediation and management strategies can address these concerns. Gentle remediation options (GRO) are scalable nature-based techniques which provide significant opportunities for multi-functionality: managing risks posed by contaminants and at the same time enhance ecosystem services (ES) by improving the soil ecosystem in a low-impact, cost-effective manner. GRO align with an increasing interest in taking a holistic view on soil and land management to protect and improve the soil ecosystem for direct human benefit in the form of ES as well as for its indirect, intrinsic value as a haven for biodiversity. This short review aims to present a synthesis of ideas to raise awareness for urban planners about GRO techniques as nature-based solutions which can promote green infrastructure in the urban environment

Impact of treatment plant management on human health and ecological risks from wastewater irrigation in developing countries - case studies from Cochabamba, Bolivia

Wastewater irrigation is a common practice in developing countries due to water scarcity and increasing demand for food production. However, there are health risks and ecological risks associated with this practice. Small-scale wastewater treatment plants (WWTPs) intend to decrease these risks but still face management challenges. This study assessed how the management status of five small-scale WWTPs in Cochabamba, Bolivia affects health risks associated with consumption of lettuce and ecological risks due to the accumulation of nutrients in the soil for lettuce and maize crops. Risk simulations for three wastewater irrigation scenarios were: raw wastewater, actual effluent and expected effluent. Results showed that weak O&M practices can increase risk outcomes to higher levels than irrigating with raw wastewater. Improving O&M to achieve optimal functioning of small-scale WWTPs can reduce human health risks and ecological risks up to 2 log(10) DALY person(-1) year(-1) and to 2 log(10) kg nitrogen ha(-1) accumulated in soil, respectively

Integrating Ecosystem Services into Risk Assessments for Drinking Water Protection

Water protection is a widely supported goal in society, but competing interests often complicate the implementation of water protection measures. Moreover, the benefits of protection efforts are typically underestimated as risk assessments focus on the provision of drinking water and neglect the additional services provided by a clean drinking water source. We developed a list of water system services (WSS) that allows assessment of all biotic and abiotic services provided by a drinking water source. The WSS were derived from the Common International Classification of Ecosystem Services (CICES). The objectives of this paper are to (i) introduce the concept of WSS, (ii) describe a procedure on how to develop a region-specific list of WSS and present a list of WSS specifically tailored to Sweden, (iii) present how to integrate WSS into a risk assessment for drinking water, and (iv) illustrate a practical application on a Swedish case study. The results, presented as an assessment matrix, show the provided services and contrast the hazard sources with their impact on all services. The WSS assessment can be used to communicate and negotiate the extent of water protection measures with relevant stakeholders and illustrate synergies and trade-offs of protective measures beyond drinking water protection