Abstract
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Pruden et al. (2018) reports the consensus from the workshop on antimicrobial resistance, which took place at the 2017 AEESP Biennial Conference. Recommended priorities for research and action are laid out to meet goals for better surveillance and monitoring, antimicrobial resistance characterization within environmental hotspots such as in wastewater treatment and agricultural operations, and risk modeling and assessment. Further hypothesis-driven research on antimicrobial propagation and links to human health is needed, and large interdisciplinary system-level studies are recommended that focus on risk characterization to develop recommendations for mitigation strategies.
Although on the decrease globally, diarrhea is still a leading cause of death in developing countries. In a study by Voth-Gaeddert et al. (2018), a structural equation model was developed to correlate diarrheal occurrence rates with socioeconomic, demographic, and health practices at communities with biosand filters. The structural equation model laid out complex associations between diarrheal occurrence and causal pathways, and higher household education levels and improved water sources had the highest negative effect sizes on diarrheal occurrence.
Grant and Hicks (2018) provide a midpoint life cycle assessment (LCA) for dairy milk, almond milk, and soy milk using two functional units: liter of milk and kilogram of protein. Twelve impact categories were analyzed including global warming potential, eutrophication, ecotoxicity, fossil fuel depletion, water intake, and cumulative energy demand. On a per liter basis, dairy milk had the highest impact in 6 of the 12 categories, but on a per kilogram of protein basis, almond milk had the highest impact on all 12 categories. The study not only provides valuable information on the LCA of these consumer products, but also highlights how functional units used in LCA analysis can lead to different results and interpretations.
Oil and natural gas production poses risks of methane intrusion into groundwater used for drinking water, and real-time field measurements pose several advantages. Ruybal et al. (2018) report on the design of a portable equilibrator to measure methane in the field. The novel design uses a venturi ejector, static mixer, and free overfall jet stream to achieve a rapid mass transfer of methane from the aqueous to air phase. The equilibrator was demonstrated during purging of six groundwater wells, and the methane concentrations were found to be in good agreement with laboratory analysis.
Determining dispersivity of solute in groundwater heavily relies on conservative tracer tests that only provide site-specific information; a priori models that can predict dispersivity are limited. Muller and Ramsburg (2018) challenged 10 previously published models developed to predict dispersivity on a data set comprised from 133 previously published experiments. The dispersivity in these experiments was determined from conservative tracer test results in fully saturated non-aqueous phase liquid (NAPL)–previously published models were found to offer predictive capabilities for dispersivity. The authors presented new empirical models that provided superior fits including one model that offers predictive capabilities irrespective of saturation level or presence of nonwetting phase.