Equipping for risk: Lessons learnt from the UK shale-gas experience on assessing environmental risks for the future geoenergy use of the deep subsurface

findings are presented from an investigation to improve understanding of the environmental risks associated with developing an unconventional-hydrocarbons industry in the UK. The EQUIPT4RISK project, funded by UK Research Councils, focused on investigations around Preston New Road (PNR), Fylde, Lancashire, and Kirby Misperton Site A (KMA), North Yorkshire, where operator licences to explore for shale gas by hydraulic fracturing (HF) were issued in 2016, although exploration only took place at PNR. EQUIPT4RISK considered atmospheric (greenhouse gases, air quality), water (groundwater quality) and solid-earth (seismicity) compartments to characterise and model local conditions and environmental responses to HF activities. Risk assessment was based on the source-pathway-receptor approach. Baseline monitoring of air around the two sites characterised the variability with meteorological conditions, and isotopic signatures were able to discriminate biogenic methane (cattle) from thermogenic (natural-gas) sources. Monitoring of a post-HF nitrogen-lift (well-cleaning) operation at PNR detected the release of atmospheric emissions of methane (4.2 ± 1.4 t CH4). Groundwater monitoring around KMA identified high baseline methane concentrations and detected ethane and propane at some locations. Dissolved methane was inferred from stable-isotopic evidence as overwhelmingly of biogenic origin. Groundwater-quality monitoring around PNR found no evidence of HF-induced impacts. Two approaches for modelling induced seismicity and associated seismic risk were developed using observations of seismicity and operational parameters from PNR in 2018 and 2019. Novel methodologies developed for monitoring include use of machine learning to identify fugitive atmospheric methane, Bayesian statistics to assess changes to groundwater quality, a seismicity forecasting model seeded by the HF-fluid injection rate and high-resolution monitoring of soil-gas methane. The project developed a risk-assessment framework, aligned with ISO 31000 risk-management principles, to assess the theoretical combined and cumulative environmental risks from operations over time. This demonstrated the spatial and temporal evolution of risk profiles: seismic and atmospheric impacts from the shale-gas operations are modelled to be localised and short-lived, while risk to groundwater quality is longer-term.

An interferon-gamma release assay as a novel biomarker in systemic lupus erythematosus

OBJECTIVE

The mycobacterium tuberculosis (TB) IFN-γ release assay (TB-IGRA) assesses peripheral blood cell release of IFN-γ upon ex vivo exposure to mitogen (IGRA-MT), TB antigen or a negative/nil control (IGRA-NL); IGRA-NL is a measure of spontaneous IFN-γ release (SIR). Here, we investigate the diagnostic associations of elevated SIR and the potential use of IGRA-NL as a novel biomarker in SLE.

METHODS

We analysed diagnostic code frequencies among 11 823 individuals undergoing TB-IGRA testing between 2010 and 2015 in a large urban US health-care system. To study the relationship between IGRA-NL and SLE, we identified 99 individuals with SLE and TB-IGRA test results then assessed correlations between IGRA-NL, normalized IGRA-NL (the quotient of IGRA-NL/IGRA-MT), disease manifestations and disease activity.

RESULTS

We identified a discovery cohort of 108 individuals with elevated SIR (>5 S.d. above median) that was significantly enriched for a limited set of diagnoses, including SLE, TB infection, haemophagocytic lymphohistiocytosis and HIV infection. In SLE patients undergoing TB-IGRA testing, normalized IGRA-NL correlated better with disease activity than did anti-dsDNA or complement levels. This relationship appeared to reflect interactions between normalized IGRA-NL and the presence of acute skin disease, hypocomplementemia, fever and thrombocytopenia.

CONCLUSION

Elevated SIR appears to be associated with a limited number of disease processes, including SLE. The diagnostic utility of SIR remains to be determined. IFN-γ activation, as measured by the TB-IGRA test, may offer a readily available tool for assessing disease activity in patients with SLE.