Enriching social and economic aspects in sustainability assessments of remediation strategies - Methods and implementation

Bioremediation of contaminated soil and groundwater by in situ biostimulation

Bioremediation by in situ biostimulation is an attractive alternative to excavation of contaminated soil. Many in situ remediation methods have been tested with some success; however, due to highly variable results in realistic field conditions, they have not been implemented as widely as they might deserve. To ensure success, methods should be validated under site-analogous conditions before full scale use, which requires expertise and local knowledge by the implementers. The focus here is on indigenous microbial degraders and evaluation of their performance. Identifying and removing biodegradation bottlenecks for degradation of organic pollutants is essential. Limiting factors commonly include: lack of oxygen or alternative electron acceptors, low temperature, and lack of essential nutrients. Additional factors: the bioavailability of the contaminating compound, pH, distribution of the contaminant, and soil structure and moisture, and in some cases, lack of degradation potential which may be amended with bioaugmentation. Methods to remove these bottlenecks are discussed. Implementers should also be prepared to combine methods or use them in sequence. Chemical/physical means may be used to enhance biostimulation. The review also suggests tools for assessing sustainability, life cycle assessment, and risk assessment. To help entrepreneurs, decision makers, and methods developers in the future, we suggest founding a database for otherwise seldom reported unsuccessful interventions, as well as the potential for artificial intelligence (AI) to assist in site evaluation and decision-making.

Community capitals and (social) sustainability: Use and misuse of asset-based approaches in environmental management

Sustainability has increasingly gained momentum as an underlying framework to orient decisions and actions in environmental management. However, while acting in view of sustainability goals is a noble intention, both the conceptualization and the implementation of sustainability remain a subject of debate. This is partly due to the widespread lack of consideration for its social dimension and the interactions this has with the environmental and economic dimensions. To this end, the Community Capitals Framework and other asset-based approaches are often used to deal with these problematic aspects of sustainability in environmental management. Through a systematic review of scientific peer-reviewed articles, this paper investigates the conceptual and practical application of such approaches. Results from our analysis show that different declinations of community capitals exist within environmental management. In all the forms they assume in the 42 frameworks identified, their employment seems effective in promoting the inclusion of social, economic and environmental dimensions when conducting sustainability assessments. However, we identified two main difficulties that challenge the application of asset-based approaches in practice. First, in most cases, capital assessment is not carried out in the planning phase of an environmental intervention in order to identify community resources; capitals are employed instead to measure the impact of an ecological change ex-post, thus being discordant with their theoretical foundations. Second, the existence of a vast array of terms to refer to community assets creates disorientation among exponents of different stakeholder groups and hinders a practical and effective application of this concept. On the basis of our results, we claim the importance of conducting community resources assessment and stakeholder consultation at different times and through practice oriented approaches and cross-silos communication efforts in order to develop a shared understanding of the problem and facilitate sustainable, adaptive and participatory approaches to environmental management.

DynSus: Dynamic sustainability assessment in groundwater remediation practice

Decision-making processes for clean-up of contaminated sites are often highly complex and inherently uncertain. It depends not only on hydrological and biogeochemical site variability, but also on the associated health, environmental, economic, and social impacts of taking, or not taking, action. These variabilities suggest that a dynamic framework is required for promoting sustainable remediation. For this, the decision support system DynSus is presented here for integrating a predeveloped contaminant fate and transport model with a sustainability assessment tool. Implemented within a system dynamics framework, the new tool uses model simulations to provide remediation scenario analysis and handling of uncertainty in various data. DynSus was applied to a site in south Sweden, contaminated with pentachlorophenol (PCP). Simulation scenarios were developed to enable a comparison between alternative remediation strategies and combinations of these. Such comparisons are provided for selected sustainability indicators and remediation performance (in terms of concentration at the recipient). This leads to identifying the most critical variables to ensure that sustainable solutions are chosen. Simulation results indicated that although passive practices, e.g., monitored natural attenuation, were more sustainable at first (5-7 years after beginning remediation measures), they failed to compete with more active practices, e.g., bioremediation, over the entire life cycle of the project (from the beginning of remedial action to achieving the target concentration at the recipient). In addition, statistical tools (clustering and genetic algorithms) were used to further assess the available hydrogeochemical data. Taken together, the results reaffirmed the suitability of the simple analytical framework that was implemented in the contaminant transport model. DynSus outcomes could therefore enable site managers to evaluate different scenarios more quickly and effectively for life cycle sustainability in such a complex and multidimensional problem.

Analysis of Agro Alternatives to Boost Cameroon’s Socio-Environmental Resilience, Sustainable Development, and Conservation of Native Forests

Located in Central Africa, Cameroon is a country with strong social inequalities and fragile governance and institutions. This has a direct impact on the sustainable development of its territory, communities, and native forest, which are subject to constant socio-environmental and economic pressures due to overexploitation. This research has three purposes: (1) to conduct a comparative theoretical/empirical diagnosis on the quality of Cameroon’s institutional framework, governance, and public policies related to territorial sustainability; (2) to assess the impact of the three clusters identified among the 44 stakeholders interviewed (forestry companies/certifiers; NGOs/communities; and banks/public institutions) on each other; and (3) to analyze the contribution of the use of cassava (Manihot esculenta) as an agro alternative to Cameroon’s socio-ecological resilience, sustainable development, and conservation of native forests. The research found: (1) the need for mixed governance with joint accountability to find equitable and lasting sustainable solutions for the parties involved, making communities/ethnic groups visible in the decision-making process; and (2) the agro use of cassava has a positive impact on socio-ecological resilience by contributing to employment, the protection of devastated soils, and the provision of quality food, and by reducing pollution from the cement industry through using cassava waste as an input.

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.

INSIDE-T: A Groundwater Contamination Transport Model for Sustainability Assessment in Remediation Practice

Current sustainability assessment (SA) tools to help deal with contaminated groundwater sites are inherently subjective and hardly applied. One reason may be lack of proper tools for addressing contaminant spread which are basically objective. To fill this gap, there is a need for contaminant transport models that provide site managers with needed room for applying their judgments and considerations about the efficiency of each remediation method based on their experiences in similar cases. INSIDE-T uses trend analysis and inverse modeling to estimate transport parameters. It then simulates contaminant transport both with and without the inclusion of remedial actions in a transparent way. The sustainability of each remedy measure can then be quantified based on the underlying SA tool (INSIDE). INSIDE-T was applied to a site in south Sweden, contaminated with pentachlorophenol. Simulation scenarios were developed to enable comparison between various remediation strategies and combinations of these. The application indicated that natural attenuation was not a viable option within the timeframe of interest. Although pump-and-treat combined with a permeable reactive barrier was found to be just as effective as bioremediation after five years, it received a much lower sustainability score overall. INSIDE-T outcomes enable site managers to test and evaluate different scenarios, a necessity in participatory decision-making practices such as remediation projects.

Objective indicators contribute more than subjective beliefs to resident willingness to pay for ecosystem services on the Tibetan Plateau

Effective ecosystem management on the Tibetan Plateau will contribute to regional environmental sustainability, and these efforts need broad public support, especially that of residents, over the long run. Although residents' subjective perceptions often directly influence practices, the interactive effects of subjective and objective indicators at the individual level often interfere with resident participation in ecosystem management. With the objective of decoupling the effects of multiple variables on resident participation in environmental sustainability, we launched a questionnaire survey on the topic of willingness to pay (WTP) on the Tibetan Plateau, and explored the effects of single variables and pairwise variables on WTP via dummy regression and proposed specific management suggestions. The results showed that objective indicators were the key drivers of WTP. First, it not only had strong direct effects on WTP (2770.32 CNY/year) but also interacted with subjective beliefs (3805.92 CNY/year); second, it had indirect effects on participation attitudes (R = 0.79) through subjective beliefs (R = 0.38). Put differently, the challenge of achieving sustainable management in the TP is how to enhance and satisfy the sociodemographic and socio-economic attributes of indigenous residents.

INSIDE: An efficient guide for sustainable remediation practice in addressing contaminated soil and groundwater

Modeling criteria interaction in decision-making problems is complex and often neglected. In complicated problems, like contaminated site remediation projects, independency of involved criteria is not a realistic assumption. INfluence based deciSIon guiDE (INSIDE) is a methodology that enables sustainable decision making and management in contaminated site remediation practice. Unlike most previous decision-support methods, INSIDE considers realistic interactions among all involved criteria. The method not only gives a one-time best option for choosing a remediation method for the project at hand, but also a management plan for further improvements of the system. INSIDE recognizes economic, environmental, social, and technological considerations for the most sustainable practice. Eight criteria are defined based on these aspects and they can be interrelated. This means that a criterion, e.g., remediation time, does not need to belong to any pre-defined category such as economic, environmental, social, or technical, but can interact with other criteria. This allows for a system with many degrees of freedom that is more realistic for practical problem-solving. In INSIDE, the DEcision MAking Trial and Evaluation Laboratory (DEMATEL) and Analytic Network Process (ANP) techniques are combined for assigning weights to criteria and scoring of remediation alternatives, respectively. Thus, the proposed methodology gives a managerial cone of influence versus importance for all involved criteria in the system. The method is applied to a data-scarce case study in Iran to prioritize between remediation methods for a contaminated groundwater aquifer. The results show that human health risk and environmental impacts are more influential than other evaluated criteria. The suggested methodology should be further tested on a variety of actual remediation problems for additional evaluation.