Assessing explicit models of per- and polyfluoroalkyl substances adsorption on anion exchange resins by rapid small-scale column tests.

Managing per- and polyfluoroalkyl substance (PFAS) contamination has gained worldwide attention due to their ubiquitous occurrence in water systems. Anion exchange resins (AERs) have been proven effective in removing both long-chain and short-chain PFASs. In this study, an explicit model was developed to describe the breakthrough behavior of an individual PFAS as a single solute onto anion exchange resin in a column filtration process. The model was further modified to predict the breakthrough curve of co-existing PFASs on AER in multi-solute systems by incorporating a separation factor describing the competitive adsorption and a blockage factor describing the loss of adsorption sites. Rapid small-scale column tests (RSSCTs) were performed with six AERs of various properties and three model PFASs in both single- and multi-solutes systems. The breakthrough behaviors of RSSCTs for both single- and multi-solute systems were found adequately described by the models developed in this study. The experiments and accompanied model simulations reveal some important relationships between the AER performance and the properties of both the AERs and the PFASs.

Socioeconomic deprivation and ethnicity inequalities in disruption to NHS hospital admissions during the COVID-19 pandemic: a national observational study.

INTRODUCTION: Hospital admissions in many countries fell dramatically at the onset of the COVID-19 pandemic. Less is known about how care patterns differed by patient groups. We sought to determine whether areas with higher levels of socioeconomic deprivation or larger ethnic minority populations saw larger falls in emergency and planned admissions in England. METHODS: We conducted a national observational study of hospital care in the English National Health Service (NHS) in 2019-2020. Weekly volumes of elective (planned) and emergency admissions in 2020 compared with 2019 were calculated for each census area. Multiple linear regression analysis was used to estimate the reductions in volumes for areas in different quintiles of socioeconomic deprivation and ethnic minority populations after controlling for national time trends and local area composition. RESULTS: Between March and December 2020, there were 35.5% (3.0 million) fewer elective admissions and 22.0% (1.2 million) fewer emergency admissions with a non-COVID-19 primary diagnosis than in 2019. Areas with the largest share of ethnic minority populations experienced a 36.7% (95% CI 24.1% to 49.3%) larger reduction in non-primary COVID-19 emergency admissions compared with those with the smallest. The most deprived areas experienced a 10.1% (95% CI 2.6% to 17.7%) smaller reduction in non-COVID-19 emergency admissions compared with the least deprived. These patterns are not explained by differential prevalence of COVID-19 cases by area. CONCLUSIONS: Even in a healthcare system founded on the principle of equal access for equal need, the impact of COVID-19 on NHS hospital care for non-COVID patients has not been spread evenly by ethnicity and deprivation in England. While we cannot conclusively determine the mechanisms behind these differences, they risk exacerbating prepandemic health inequalities.