Comprehensive review of several surfactants in marine environments: Fate and ecotoxicity.

Surfactants are a commercially important group of chemicals widely used on a global scale. Despite high removal efficiencies during wastewater treatment, their high consumption volumes mean that a certain fraction will always enter aquatic ecosystems, with marine environments being the ultimate sites of deposition. Consequently, surfactants have been detected within marine waters and sediments. However, aquatic environmental studies have mostly focused on the freshwater environment, and marine studies are considerably underrepresented by comparison. The present review aims to provide a summary of current marine environmental fate (monitoring, biodegradation, and bioconcentration) and effects data of 5 key surfactant groups: linear alkylbenzene sulfonates, alcohol ethoxysulfates, alkyl sulfates, alcohol ethoxylates, and ditallow dimethyl ammonium chloride. Monitoring data are currently limited, especially for alcohol ethoxysulfates and alkyl sulfates. Biodegradation was shown to be considerably slower under marine conditions, whereas ecotoxicity studies suggest that marine species are approximately equally as sensitive to these surfactants as freshwater species. Marine bioconcentration studies are almost nonexistent. Current gaps within the literature are presented, thereby highlighting research areas where additional marine studies should focus.

Another civilian life saved by law enforcement-applied tourniquets.

Increasing data and anecdotal operational reports are supporting the early, aggressive, prehospital application of tourniquets in potentially life-threatening extremity trauma. Especially in the civilian urban setting where transport times are short, the benefit in terms of lives saved far outweighs the potential risk to the extremity. The popular press has reported frequently on law enforcement-applied tourniquets, but to date, no group has published a scientific review of any of these cases. This case report suggests that law enforcement personnel can be trained to safely identify indications for tourniquet application, properly apply them with limited training, and function as effective first care providers.

Modeling the impact of direct phototransformation on predicted environmental concentrations (PECs) of propranolol hydrochloride in UK and US rivers.

There is currently uncertainty on the persistence of active pharmaceutical ingredients (APIs) and on their depletion mechanisms in natural surface waters such as rivers, and hence predictions of their fate are often poor. In this study, a beta-adrenergic receptor, propranolol hydrochloride, was selected as a model API to explore the relative significance of direct phototransformation as a potential removal process of hydrophilic APIs in rivers. Phototransformation kinetics of propranolol was measured under simulated solar irradiation in the laboratory, which were then converted to the kinetics applicable in UK and US rivers. The effects of light intensity, light penetration, river size and flow were examined. The extrapolated phototransformation half-lives were applied in the river catchment models of GREAT-ER and PhATE. Results demonstrated that direct phototransformation significantly reduced the predicted environmental concentrations of propranolol in the water phase. Predicted reductions of mean concentrations in the River Aire (UK) were 27% in summer and 3% in winter; and for the US rivers simulated, reductions were 28-68% in summer and 11-41% in winter. The highest reductions were predicted for long rivers with low turbidity and low flow conditions.

Estimating spatial patterns of effluent exposure concentrations in direct toxicity assessment studies.

Hydrodynamic models of differing scale and complexity were used to estimate spatial patterns of effluent concentration in discharge plumes in the River Esk and the Lower Tees Estuary. The output from the Tees model was used, in conjunction with measurements of toxicity determined in short-term oyster embryo tests, to predict contours/zones of toxicity in the estuary associated with effluent discharges from four chemical processing sites. One of the discharges also combined the input from a municipal sewage treatment works. The models appeared to be effective in predicting patterns of dilution and dispersion of the effluent discharges in the respective receiving environments. Confirmation of the predictive capabilities of the Tees model was achieved by comparing predicted and measured toxicity in different regions of the plumes associated with the four discharges. Differences between predicted and measured toxicity for two of the four discharges were explicable in terms of failure to take account of the effects of real-time wind conditions when test samples were collected or overlap of adjacent discharge plumes. Suggested refinements to the models and measurement of effluent toxicity would further enhance the utility of this approach for determining the extent and significance of the effects of effluent discharges in receiving environments.