Coastal oil spills constitute significant threat to biotic energy distribution, and biodiversity integrity amongst others. This study monitored the recovery of low-intertidal, soft-bottom infauna macrobenthic invertebrates in Bodo Creek intermittently over a 7-year period post oil spill. Samples were taken twice a month (spring and neap low tides) for 6 months (September 2015–February 2016) at sites previously studied (pre-spill baseline studies, 3-year and 5-year post-spill studies) for the effects of oil pollution using the same sampling methods used during initial studies of the same area. Comparatively, the initial studies reported Polychaeta as the dominant class against the dominant Crustacea reported in this 7-year post-spill study, indicating a change in the community structure of the study area. Infauna macro-invertebrate communities recorded showed an improvement (that is, increased species richness and number of individuals) over the initial 3-year and 5-year post-spill studies. However, relating the results to the initial baseline pre-spill studies, an annual average of 9.7% recovery rate was observed. Analysis of results showed that the total hydrocarbon content (THC) of the sediment remained high (90.08–12,184 mg/kg) but was markedly lower than levels observed during the initial post-spill study (6422–7186 mg/kg). Tidal flushing and biodegradation processes were deemed responsible for the reduction in THC. This study provides a rare dataset that describes the effects of oil pollution on a previously near-pristine estuarine environment in the tropics.

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.

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.

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.

A six-month laboratory scale study was carried out to investigate the effect of biochar and compost amendments on complex chemical mixtures of tar, heavy metals and metalloids in two genuine contaminated soils. An integrated approach, where organic and inorganic contaminants bioavailability and distribution changes, along with a range of microbiological indicators and ecotoxicological bioassays, was used to provide multiple lines of evidence to support the risk characterisation and assess the remediation end-point. Both compost and biochar amendment (p = 0.005) as well as incubation time (p = 0.001) significantly affected the total and bioavailable concentrations of the total petroleum hydrocarbons (TPH) in the two soils. Specifically, TPH concentration decreased by 46% and 30% in Soil 1 and Soil 2 amended with compost. These decreases were accompanied by a reduction of 78% (Soil 1) and 6% (Soil 2) of the bioavailable hydrocarbons and the most significant decrease was observed for the medium to long chain aliphatic compounds (EC16-35) and medium molecular weight aromatic compounds (EC16-21). Compost amendment enhanced the degradation of both the aliphatic and aromatic fractions in the two soils, while biochar contributed to lock the hydrocarbons in the contaminated soils. Neither compost nor biochar affected the distribution and behaviour of the heavy metals (HM) and metalloids in the different soil phases, suggesting that the co-presence of heavy metals and metalloids posed a low risk. Strong negative correlations were observed between the bioavailable hydrocarbon fractions and the ecotoxicological assays suggesting that when bioavailable concentrations decreased, the toxicity also decreased. This study showed that adopting a combined diagnostic approach can significantly help to identify optimal remediation strategies and contribute to change the over-conservative nature of the current risk assessments thus reducing the costs associated with remediation endpoint.

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.

Understanding the distribution, behaviour and interactions of complex chemical mixtures is key for providing the evidence necessary to make informed decisions and implement robust remediation strategies. Much of the current risk assessment frameworks applied to manage land contamination are based on total contaminant concentrations and the exposure assessments embedded within them do not explicitly address the partitioning and bioavailability of chemical mixtures. These oversights may contribute to an overestimation of both the eco-toxicological effects of the fractions and the mobility of contaminants. In turn, this may limit the efficacy of risk frameworks to inform targeted and proportionate remediation strategies. In this review we analyse the science surrounding bioavailability, its regulatory inclusion and the challenges of incorporating bioavailability in decision making process. While a number of physical and chemical techniques have proven to be valuable tools for estimating bioavailability of organic and inorganic contaminants in soils, doubts have been cast on its implementation into risk management soil frameworks mainly due to a general disagreement on the interchangeable use of bioavailability and bioaccessibility, and the associated methods which are still not standardised. This review focuses on the role of biotic and abiotic factors affecting bioavailability along with soil physicochemical properties and contaminant composition. We also included advantages and disadvantages of different extraction techniques and their implications for bioavailability quantitative estimation. In order to move forward the integration of bioavailability into site-specific risk assessments we should (1) account for soil and contaminant physicochemical characteristics and their effect on bioavailability; (2) evaluate receptor's potential exposure and uptake based on mild-extraction; (3) adopt a combined approach where chemical-techniques are used along with biological methods; (4) consider a simplified and cost-effective methodology to apply at regulatory and industry setting; (5) use single-contaminant exposure assessments to inform and predict complex chemical mixture behaviour and bioavailability.

Communicating the rationale for allocating resources to manage policy priorities and their risks is challenging. Here, we demonstrate that environmental risks have diverse attributes and locales in their effects that may drive disproportionate responses among citizens. When 2,065 survey participants deployed summary information and their own understanding to assess 12 policy-level environmental risks singularly, their assessment differed from a prior expert assessment. However, participants provided rankings similar to those of experts when these same 12 risks were considered as a group, allowing comparison between the different risks. Following this, when individuals were shown the prior expert assessment of this portfolio, they expressed a moderate level of confidence with the combined expert analysis. These are important findings for the comprehension of policy risks that may be subject to augmentation by climate change, their representation alongside other threats within national risk assessments, and interpretations of agency for public risk management by citizens and others.

8 The Ogoniland region of the Niger Delta contains a vast number of sites contaminated with 9 petroleum hydrocarbons that originated from Nigeria’s active oil sector. The United Nations 10 Environment Program (UNEP) reported on this widespread contamination in 2011, however, 11 wide-scale action to clean-up these sites has yet to be initiated. A challenge for decision 12 makers responsible for the clean-up of these sites has been the prioritisation of sites to enable 13 appropriate allocation of scarce resources. In this study, a risk-based multi-criteria decision 14 analysis framework was used to prioritise high-risk sites contaminated with petroleum 15 hydrocarbons in the Ogoniland region of Nigeria. The prioritisation method used a set of 16 attributes relevant to the Niger Delta region that took into account chemical and ecological 17 impacts, as well as socio-economic impacts, which provided a holistic assessment of the risk. 18 Data for the analysis was taken from the UNEP Environmental Assessment of Ogoniland. 19 Over 110 communities were affected by oil-contaminated land, of which eight sites were 20 contaminated with petroleum hydrocarbons in excess of five times the regulatory threshold. 21

Membranes can potentially offer low-cost CO2 capture from post-combustion flue gas. However, the low partial pressure of CO2 in flue gases can inhibit their effectiveness unless methods are employed to increase their partial pressure. Selective-Exhaust Gas Recirculation (S-EGR) has recently received considerable attention. In this study, the performance of a dense polydimethylsiloxane (PDMS) membrane for the separation of CO2/N2 binary model mixtures for S-EGR application was investigated using a bench-scale experimental rig. Measurements at different pressures, at different feeding concentrations and with nitrogen as sweep gas revealed an average carbon dioxide permeability of 2943 ± 4.1%RSD Barrer. The bench-scale membrane module showed high potential to separate binary mixtures of N2 and CO2 containing 5–20% CO2. The permeability was slightly affected by feed pressures ranging from 1 to 2.4bar. Furthermore, the separation selectivity for a CO2/N2 mixture of 10%/90% (by volume) reached a maximum of 10.55 at 1.8bar. Based on the results from the bench-scale experiments, a pilot-scale PDMS membrane module was tested for the first time using a real flue gas mixture taken from the combustion of natural gas. Results from the pilot-scale experiments confirmed the potential of the PDMS membrane system to be used in an S-EGR configuration for capture of CO2.

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.

Carbon capture and storage (CCS) from natural gas-fired systems is an emerging field and many of the concepts and underlying scientific principles are still being developed. Preliminary studies suggest this approach can boost the CO2 content in the feed gas up to 3 times compared to the 'no recycle' case (CO2 concentration increased to 18% vs. 6%), with a consequent reduction in flow to the post-combustion capture unit by a factor of three compared to conventional, non-S-EGR. For this project, Cranfield University developed a pilot-scale 100 kW CO2 membrane rig facility in order to investigate simultaneously EGR and S-EGR technologies, the latter being achieved by using a CO2 sweep air polymeric membrane. A bench-scale membrane rig has also been developed to investigate the permeability and selectivity of different polymeric membranes to CO2. Currently a small-scale polydimethylsiloxane (PDMS) membrane module is also being investigated to study its selectivity/permeability. The tests include exploring the performance improvement of the PDMS membrane using different operating conditions with a view to developing scale-up procedures for the membrane unit for the actual 100 kW pilot-scale rig. Process simulations were performed using Aspen Plus software to predict the behaviour of the pilot-scale rig using a model developed based on empirical parameters (i.e., mass transfer coefficient of CO2 through the membrane and permeance), measured in the bench-scale membrane test unit. The results show that CO2 concentrations of up to 14.9% (comparable to CO2 level in coal combustion) can be achieved with 60% EGR, with a 90% CO2 removal efficiency of the membrane units. However, the results generated with the membrane model in which specific permeance values to PDMS were applied, predicted concentrations of CO2 in flue gases up to 9.8% (v/v) for a selective recycle of 60%. The study shows that the S-EGR technique is an effective method that can provide similar conditions to that of a coal-fired power plant for the post-combustion capture system operating on natural gas-fired units, but also highlights the fact that more research is required to find more suitable materials for membranes that optimise the CO2 removal efficiencies from the flue gas.

Strategic risk appraisal (SRA) has been applied to compare diverse policy level risks to and from the environment in England and Wales. Its application has relied on expert-informed assessments of the potential consequences from residual risks that attract policy attention at the national scale. Here we compare consequence assessments, across environmental, economic and social impact categories that draw on 'expert'- and 'literature-based' analyses of the evidence for 12 public risks appraised by Government. For environmental consequences there is reasonable agreement between the two sources of assessment, with expert-informed assessments providing a narrower dispersion of impact severity and with median values similar in scale to those produced by an analysis of the literature. The situation is more complex for economic consequences, with a greater spread in the median values, less consistency between the two assessment types and a shift toward higher severity values across the risk portfolio. For social consequences, the spread of severity values is greater still, with no consistent trend between the severities of impact expressed by the two types of assessment. For the latter, the findings suggest the need for a fuller representation of socioeconomic expertise in SRA and the workshops that inform SRA output.

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.

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.

There are a number of specific opportunities for UK and China to work together on contaminated land management issues as China lacks comprehensive and systematic planning for sustainable risk based land management, encompassing both contaminated soil and groundwater and recycling and reuse of soil. It also lacks comprehensive risk assessment systems, structures to support risk management decision making, processes for verification of remediation outcome, systems for record keeping and preservation and integration of contamination issues into land use planning, along with procedures for ensuring effective health and safety considerations during remediation projects, and effective evaluation of costs versus benefits and overall sustainability. A consequence of the absence of these overarching frameworks has been that remediation takes place on an ad hoc basis. At a specific site management level, China lacks capabilities in site investigation and consequent risk assessment systems, in particular related to conceptual modelling and risk evaluation. There is also a lack of shared experience of practical deployment of remediation technologies in China, analogous to the situation before the establishment of the independent, non-profit organisation CL:AIRE (Contaminated Land: Applications In Real Environments) in 1999 in the UK. Many local technology developments are at lab-scale or pilot-scale stage without being widely put into use. Therefore, a shared endeavour is needed to promote the development of technically and scientifically sound land management as well as soil and human health protection to improve the sustainability of the rapid urbanisation in China.

The potential for biotransformation of weathered hydrocarbon residues in soils collected from two commercial oil refinery sites (Soil A and B) was studied in microcosm experiments. Soil A has previously been subjected to on-site bioremediation and it was believed that no further degradation was possible while soil B has not been subjected to any treatment. A number of amendment strategies including bioaugmentation with hydrocarbon degrader, biostimulation with nutrients and soil grinding, were applied to the microcosms as putative biodegradation improvement strategies. The hydrocarbon concentrations in each amendment group were monitored throughout 112 days incubation. Microcosms treated with biostimulation (BS) and biostimulation/bioaugmentation (BS + BA) showed the most significant reductions in the aliphatic and aromatic hydrocarbon fractions. However, soil grinding was shown to reduce the effectiveness of a nutrient treatment on the extent of biotransformation by up to 25% and 20% for the aliphatic and aromatic hydrocarbon fractions, respectively. This is likely due to the disruption to the indigenous microbial community in the soil caused by grinding. Further, ecotoxicological responses (mustard seed germination and Microtox assays) showed that a reduction of total petroleum hydrocarbon (TPH) concentration in soil was not directly correlable to reduction in toxicity; thus monitoring TPH alone is not sufficient for assessing the environmental risk of a contaminated site after remediation.

Interest in the development of shale gas resources using hydraulic fracturing techniques is increasing worldwide despite concerns about the environmental risks associated with this activity. In the United Kingdom (UK), early attempts to hydraulically fracture a shale gas well resulted in a seismic event that led to the suspension of all hydraulic fracturing operations. In response to this occurrence, UK regulators have requested that future shale gas operations that use hydraulic fracturing should be accompanied by a high-level environmental risk assessment (ERA). Completion of an ERA can demonstrate competency, communicate understanding, and ultimately build trust that environmental risks are being managed properly, however, this assessment requires a scientific evidence base. In this paper we discuss how the ERA became a preferred assessment technique to understand the risks related to shale gas development in the UK, and how it can be used to communicate information between stakeholders. We also provide a review of the evidence base that describes the environmental risks related to shale gas operations, which could be used to support an ERA. Finally, we conclude with an update of the current environmental risks associated with shale gas development in the UK and present recommendations for further research.

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.