Safety climate: Leading or lagging indicator of safety outcomes?

This paper theorizes how and why safety climate can be conceived as both a leading and a lagging indicator of safety events (i.e., accidents, injuries). When safety climate is conceived as a leading indicator, a prospective design is utilized and safety climate data are correlated with accidents/injuries that occur in the future. When safety climate is conceived as a lagging indicator, retrospective designs are used in which safety climate data are correlated with prior accidents/injuries. We examine the research literature to reveal that safety climate has been investigated as both a leading and a lagging indicator, but it is usually only examined as one or the other within a given study and has been examined as a lagging indicator most frequently. Consistent with our theorizing, prospective designs yield stronger relationships than retrospective designs, suggesting that safety climate is a better leading indicator than lagging indicator; however, it is clearly both. Implications for safety climate research and study design are discussed.     

Influence of feeding procedure on biomarkers in caged rainbow trout (Oncorhynchus mykiss) used in environmental monitoring

Biomarkers in feral fish can be a useful tool for environmental monitoring of aquatic ecosystems. Drawbacks, however, are that suitable fish species are not always available and that natural variations can bias the results. An alternative strategy is to use farmed fish placed in cages. There is, however, still a risk that factors other than pollution level could have an impact on the biomarkers and the observed responses in the fish. The present study evaluates the effects of feeding procedure on biomarkers in caged fish. Two feeding rations (2% and 8% weekly feeding) have been examined for a large number of biomarkers in caged rainbow trout (Oncorhynchus mykiss). Significant effects of feeding rations were found on hepatic ethoxyresorufin-O-deethylase (EROD) and catalase activity, PAH metabolites in bile, plasma ion concentrations and the presence of immature red blood cells. The influence on EROD activity and PAH metabolites seems to be caused by elevated uptake of pollutants when feeding ratios are higher. The effects on other biochemical and physiological variables are more likely caused by stress due to insufficient feeding. According to these results, valid comparison of fish groups in environmental monitoring requires standardized feeding levels.     

In-situ application of colloidal activated carbon for PFAS-contaminated soil and groundwater: A Swedish case study

Soil and groundwater contamination by per- and polyfluoroalkyl substances (PFAS) has been a significant concern to human health and environmental quality. Remediation of contaminated sites is crucial to prevent plume expansion but can prove challenging due to the persistent nature of PFAS combined with their high aqueous mobility. In this case study, we investigated the potential of colloidal activated carbon (CAC) for soil stabilization at the pilot scale, aiming to entrap PFAS and prevent their leaching from soil into groundwater. Monitoring of the site revealed the presence of two potential sources of PFAS contamination at concentrations up to 23 μg L⁻¹ for ∑₁₁PFAS in groundwater. After CAC application, initial results indicated a 76% reduction of ∑₁₁PFAS and high removal rates for long-chain PFAS, such as perfluorooctane sulfonic acid and perfluorooctanoic acid. A spike in concentrations was noticed 6 months after injection of CAC, showing a rebound of the plume and a reduction of treatment effectiveness. Based on long-term monitoring data, the treatment effectiveness for ∑₁₁PFAS dropped to 52%. The rebound of concentrations was attributed to the plume bypass of the barrier due to the presence of high conductivity zones, which likely occurred because of seasonal changes in groundwater flow directions or the CAC application at the site. This demonstrates the need for a detailed and accurate hydrogeological understanding of contaminated sites before designing and applying stabilization techniques, especially at sites with high geologic and hydrologic complexity. The results herein can serve as a guideline for treating similar sites and help avoid potential pitfalls of remedial efforts.