Effect of an extreme flood event on solute transport and resilience of a mine water treatment system in a mineralised catchment

Extreme rainfall events are predicted to become more frequent with climate change and can have a major bearing on instream solute and pollutant transport in mineralised catchments. The Coledale Beck catchment in north-west England was subject to an extreme rainfall event in December 2015 that equated to a 1 in 200-year event. The catchment contains the UK's first passive metal mine water treatment system, and as such had been subject to intense monitoring of solute dynamics before and after commissioning. Due to this monitoring record, the site provides a unique opportunity to assess the effects of a major storm event on (1) catchment-scale solute transport, and (2) the resilience of the new and novel passive treatment system to extreme events. Monitoring suggests a modest decline in treatment efficiency over time that is not synchronous with the storm event and explained instead by changes in system hydraulic efficiency. There was no apparent flushing of the mine system during the event that could potentially have compromised treatment system performance. Analysis of metal transport in the catchment downstream of the mine suggests relatively subtle changes in instream chemistry with modest but statistically-significant reductions in zinc in the lower catchment irrespective of flow condition after the extreme event, but most parameters of interest show no significant change. Increased export of colloidal iron and aluminium is associated with major landslips in the mid-catchment after the storm and provide fresh sorption sites to attenuate dissolved zinc more rapidly in these locations, corroborated by laboratory experiments utilising site materials to investigate the attenuation/release of metals from stream and terrestrial sediments. The data are important as they show both the resilience of passive mine water treatment systems to extreme events and the importance of catchment-scale monitoring to ensure continued effectiveness of treatment initiatives after major perturbation

Randomised controlled trials in the evaluation of non-biomedical therapeutic interventions for pain: The gold standard?

This paper offers a critical review of important issues in the implementation and interpretation of randomised controlled trials (RCTs) used to evaluate non-biomedical therapeutic interventions for pain. The analysis of methodological issues focuses on the validity, relevance and clinical importance of outcome measures; sampling and randomization bias; blinding procedures used to control for the placebo response and therapist influences, and treatment standardisation. A key issue is that pain management is inextricably linked to the establishment of a therapeutic relationship. In such circumstances, it is argued that the 'gold standard' double-blind RCT is impracticable. Those relying on RCTs as sources of evidence need to be aware that an 'unblinded' RCT can enhance placebo responses to the intervention and introduce important sources of bias. The challenge faced by healthcare researchers is to identify alternative research designs able to provide valid and reliable evidence that the proposed therapeutic intervention is capable of achieving cost-effective, clinically important and personally relevant outcomes in naturalistic settings