Assessing unconventional natural gas development: understanding risks in the context of the EU

Unconventional natural gas development (UNGD, e.g. shale gas) poses a threat to the environment and human health. While the Member States of the European Union (EU) decide whether to develop this resource, they require evidence to assess the associated risks. Much of the evidence regarding the risks (e.g. contamination, exposure, disturbance) comes from the US, and we argue this evidence cannot be used by the Member States to conduct risk assessments due to demographic differences, geological differences, and differences in regulation. The EU, as a whole, has recognized their need for evidence and has funded research partnerships to explore the environmental effects of UNGD. We argue that such research efforts need to be extended further in order to address the gaps in human health studies and to develop comprehensive environmental baseline studies

UK Foot and Mouth disease: a systemic risk assessment of existing controls

This article details a systemic analysis of the controls in place and possible interventions available to further reduce the risk of a foot and mouth disease (FMD) outbreak in the United Kingdom. Using a research-based network analysis tool, we identify vulnerabilities within the multibarrier control system and their corresponding critical control points (CCPs). CCPs represent opportunities for active intervention that produce the greatest improvement to United Kingdom's resilience to future FMD outbreaks. Using an adapted ‘features, events, and processes’ (FEPs) methodology and network analysis, our results suggest that movements of animals and goods associated with legal activities significantly influence the system's behavior due to their higher frequency and ability to combine and create scenarios of exposure similar in origin to the U.K. FMD outbreaks of 1967/8 and 2001. The systemic risk assessment highlights areas outside of disease control that are relevant to disease spread. Further, it proves to be a powerful tool for demonstrating the need for implementing disease controls that have not previously been part of the system

Scientific commentary: Strategic analysis of environmental policy risks-heat maps, risk futures and the character of environmental harm

We summarise our recent efforts on the policy level risk appraisal of environmental risks. These have necessitated working closely with policy teams and a requirement to maintain crisp and accessible messages for policy audiences. Our comparative analysis uses heat maps, supplemented with risk narratives, and employs the multidimensional character of risks to inform debates on the management of current residual risk and future threats. The policy research and ensuing analysis raises core issues about how comparative risk analyses are used by policy audiences, their validation and future developments that are discussed in the commentary below

Working towards an integrated land contamination management framework for Nigeria

Over the past five decades, Nigeria has developed a number of contaminated land legislations to address the damage caused primarily by oil and gas exploitation activities. Within these legislations exists elements of risk assessment and risk-based corrective action. Despite this progress, we argue that contaminated land management approaches in Nigeria need further development to be able to integrate new scientific information, and to address environmental, economic, and social values. By comparison, advanced contaminated land regimes in the United Kingdom (UK), the Netherlands, Australia, New Zealand, and the United States of America (USA) apply a number of integrative approaches (e.g. sustainability appraisal, liability regime, funding mechanisms, technology demonstration) that enable them to meet the environmental, economic, and social needs of their populations. In comparison, Nigerian governance lacks many of these mechanisms and management of contaminated land is ad hoc. In this paper we propose an integrated risk assessment framework for Nigeria that incorporates the principles of sustainability and stakeholder engagement into the decision-making processes for contaminated land risk assessment and risk management. The integrated approach relies on transparency to promote acceptance and build trust in institutions, and uses stakeholder engagement to address data deficiencies. We conclude this paper with a roadmap for how Nigeria might implement such an integrative approach into their existing contaminated land regulatory system, as well as identify a series of policy priorities that should be addressed

Energy in Africa: Policy, Management and Sustainability

African nations are experiencing rapid economic growth and development, particularly within the energy sector; however, this growth has come at a cost to the environment and society. Nowhere have these impacts been felt more precisely than in the oil and gas producing regions of Nigeria where years of neglect and mismanagement have resulted in vast areas of hydrocarbon contaminated lands. In this chapter, we present a case study of the Niger Delta. We show how constructive stakeholder engagement can be used to integrate the values and perspectives of affected communities and how this information can be used to inform environmental regulation and sustainable development. Lessons learned are relevant to other countries seeking to develop their energy resources in a sustainable manner

Use of stakeholder engagement to support policy transfer: A case of contaminated land management in Nigeria

Transfer of environmental policy from one country to another without consideration for the contextual differences (e.g. socio-cultural, economic) between the countries can be a barrier that prevents adoption, or limits the implementation and effectiveness of that policy. In this study, we investigate the socio-cultural preferences of stakeholders in the Niger Delta to understand how different stakeholder groups value socio-cultural differences. We used a modified, mixed-methods stakeholder engagement approach to capture this information, combining stakeholder workshops and interviews. Community groups, regulators, experts in contaminated land management, and oil exploration operators participated in this study, and our results revealed a general consensus concerning the ranked priority of issues. Top issues included water quality, soil quality for agriculture, food production, and human health and wellbeing. Despite this consensus, differences in how stakeholder groups arrived at their rankings might pose a challenge for policy makers. Other potential barriers to effective policy transfer identified in this study include political and cultural differences, regulatory structure, and corruption. In sum, this study provides insights about the socio-cultural preferences of stakeholders from the Niger Delta; information that could be used by policy makers to contextualise contaminated land management policy transfer

Management of petroleum hydrocarbon contaminated sites in Nigeria: Current challenges and future direction

Sites affected by petroleum hydrocarbons from oil exploitation activities have been identified as a major environmental and socio-economic problem in the Niger Delta region of Nigeria. The current Nigerian regulatory instruments to manage these contaminated sites are fragmented and the roles and responsibilities of government agencies, such as the Department for Petroleum Resources (DPR), and the National Oil Spill Detection and Response Agency (NOSDRA), are not well defined. This lack of coordination has led to ineffective land contamination policy and poor enforcement more generally. Appropriate, risk-based policy instruments are needed to improve regulatory capacity, and to enhance the regulator's ability to manage new and existing petroleum hydrocarbons contaminated sites. Lessons can be learned from countries like the United Kingdom (UK) and the United States America (USA) that have experience with the management and clean up of historically contaminated land. In this paper, we review the status of petroleum hydrocarbon contaminated sites management in Nigeria and identify the gaps in existing policy and regulation. We review the contaminated land policies and regulation from the UK and the USA, and identify lessons that could be transferred to the Nigerian system. Finally, we provide a series of recommendations (e.g. source – pathway-receptor approach, soil screening criteria, clean-up funding, liability) that could enhance contaminated land legislation in Nigeria

Surface Tension and Adsorption of Volatile Organic Amphiphiles in Aqueous Solution

The surface tension of an interface separating two bulk phases is one of the most widely studied properties in surface science research. The importance of surface or interfacial tension is reflected in the diverse number of applications which are influenced by surface tension related effects. This thesis represents a comprehensive experimental and theoretical investigation on molecular adsorption and surface tension from a class of organic compounds in aqueous solutions. The research illustrates the effect of both liquid and vapor phase adsorption on the interfacial properties. Adsorption from both sides of the vapor/liquid interface is considered simultaneously rather than exclusive of one another, which has been the conventional practice. In the experimental study, the surface tension of a number of different volatile organic compounds is measured using the Axisymmetric Drop Shape Analysis-Profile (ADSA-P) method. The experiments were performed in a controlled environment under conditions where the surface tension can be affected by both vapor and liquid phase adsorption. The vapor phase was exerted by the presence of an environment solution containing the same organic component as in the drop solution. The results show that initially the surface tension is influenced by the organic concentration in both the liquid and the vapor phase. At the final steady-state the liquid phase becomes less important and the primary factor influencing the surface tension is the vapor phase concentration. The ADSA-P technique is verified by reproducing a select number of cases using the Wilhelmy plate method. A possible consequence of the surface tension phenomenon is illustrated through time-dependent contact angle experiments. The behavior of the interface at steady-state conditions is investigated by measuring the surface tension response to a change in drop volume. It is concluded that the organic compounds considered in the current study may represent a rather general group of molecules whose surface behavior is unique to that of many conventional surfactants. In the theoretical study an empirical model is proposed to describe the relation between the steady-state surface tension and the concentration of the environment and drop solutions. The results confirm the experimental observation that the final steady-state surface tension is determined primarily by the organic concentration in the vapor phase. In addition, a modified adsorption isotherm is developed to account for simultaneous adsorption from both sides of the vapor/liquid interface at steady-state conditions. The derivation is based upon the classic Langmuir analysis, and the new equation is consistent with the Langmuir isotherm under traditional conditions where adsorption occurs from one side of the interface. The modified isotherm is shown to be consistent with the experimental data and is used to generate the equilibrium parameters for three of the systems studied in this research. The adsorption isotherm is then extended to model the dynamic adsorption process through the creation of a new kinetic transfer equation. As with the adsorption isotherm, the transfer equation is based on Langmuir kinetics and is capable of simulating adsorption from both sides of the interface during surface equilibration. The kinetic transfer equation is validated against experimental data from two systems which exhibit a transfer-controlled adsorption mechanism. The theoretical predictions from the transfer equation fit well with the experimental data for both systems. However, significant variability is observed in the least squares estimates of the kinetic rate constants. The variability is attributed to the limitations of empirical models that utilize adjustable fitting parameters to optimize the model predictions, and the wide range of surfactant concentrations studied. Specific concentration regions are identified where the variability in the rate constants is minimal and thus, where the model is most appropriate

Prediction of bioavailability and toxicity of complex chemical mixtures through machine learning models

Empirical data from a 6-month mesocosms experiment were used to assess the ability and performance of two machine learning (ML) models, including artificial neural network (NN) and random forest (RF), to predict temporal bioavailability changes of complex chemical mixtures in contaminated soils amended with compost or biochar. From the predicted bioavailability data, toxicity response for relevant ecological receptors was then forecasted to establish environmental risk implications and determine acceptable end-point remediation. The dataset corresponds to replicate samples collected over 180 days and analysed for total and bioavailable petroleum hydrocarbons and heavy metals/metalloids content. Further to this, a range of biological indicators including bacteria count, soil respiration, microbial community fingerprint, seeds germination, earthworm's lethality, and bioluminescent bacteria were evaluated to inform the environmental risk assessment. Parameters such as soil type, amendment (biochar and compost), initial concentration of individual compounds, and incubation time were used as inputs of the ML models. The relative importance of the input variables was also analysed to better understand the drivers of temporal changes in bioavailability and toxicity. It showed that toxicity changes can be driven by multiple factors (combined effects), which may not be accounted for in classical linear regression analysis (correlation). The use of ML models could improve our understanding of rate-limiting processes affecting the freely available fraction (bioavailable) of contaminants in soil, therefore contributing to mitigate potential risks and to inform appropriate response and recovery methods

Insights into mixed contaminants interactions and its implication for heavy metals and metalloids mobility, bioavailability and risk assessment

Mobility of heavy metals at contaminated sites is mainly influenced by the soil physicochemical properties and environmental conditions, therefore assessing heavy metals (HMs) and metalloids fractionation can provide insights into their potential risk and the mechanisms that regulate bioavailability. A 12-months mesocosms experiment was setup to investigate the effect of physicochemical factors (pH, moisture, and temperature) and weathering (time) on HMs and metalloids fractionation in three different multi-contaminated soil matrices (low, medium, and high contamination) collected from a soil treatment facility located in the United Kingdom, and two rural contaminated soil samples. The study demonstrates that even though Pb and Zn were found associated with the exchangeable fraction in the soil with the highest contamination (total average Pb 3400 mg/kg, and total average Zn 2100 mg/kg in Soil C), neither the condition applied nor the weathering caused an increase in their mobility. Although it was expected that lower pH (4.5) would favours the dissociation of HMs and metalloids, no significant differences were observed, potentially due to the initial alkaline pH of the genuine-contaminated soil samples. The results show that even though total concentration of Pb, Cu, and Zn exceed the soil standards and guideline values, HMs were predominantly associated with the non-exchangeable fraction, while only 5% were dissolved in the pore water fraction (potentially bioavailable). In addition, the mobility and bioavailability of HMs remained constant over the 12 months monitoring, suggesting that these soils pose negligible risk to the environment