Biomarker-indicated extent of oxidation of plant-derived organic carbon (OC) in relation to geomorphology in an arsenic contaminated Holocene aquifer, Cambodia

The poisoning of rural populations in South and Southeast Asia due to high groundwater arsenic concentrations is one of the world’s largest ongoing natural disasters. It is important to consider environmental processes related to the release of geogenic arsenic, including geomorphological and organic geochemical processes. Arsenic is released from sediments when iron-oxide minerals, onto which arsenic is adsorbed or incorporated, react with organic carbon (OC) and the OC is oxidised. In this study we build a new geomorphological framework for Kandal Province, a highly studied arsenic affected region of Cambodia, and tie this into wider regional environmental change throughout the Holocene. Analyses shows that the concentration of OC in the sediments is strongly inversely correlated to grainsize. Furthermore, the type of OC is also related to grain size with the clay containing mostly (immature) plant derived OC and sand containing mostly thermally mature derived OC. Finally, analyses indicate that within the plant derived OC relative oxidation is strongly grouped by stratigraphy with the older bound OC more oxidised than younger OC

Comparison of dissolved and particulate arsenic distributions in shallow aquifers of Chakdaha, India, and Araihazar, Bangladesh

International audienceBackground The origin of the spatial variability of dissolved As concentrations in shallow aquifers of the Bengal Basin remains poorly understood. To address this, we compare here transects of simultaneously-collected groundwater and aquifer solids perpendicular to the banks of the Hooghly River in Chakdaha, India, and the Old Brahmaputra River in Araihazar, Bangladesh. Results Variations in surface geomorphology mapped by electromagnetic conductivity indicate that permeable sandy soils are associated with underlying aquifers that are moderately reducing to a depth of 10–30 m, as indicated by acid-leachable Fe(II)/Fe ratios 5 mg L-1. More reducing aquifers are typically capped with finer-grained soils. The patterns suggest that vertical recharge through permeable soils is associated with a flux of oxidants on the banks of the Hooghly River and, further inland, in both Chakdaha and Araihazar. Moderately reducing conditions maintained by local recharge are generally associated with low As concentrations in Araihazar, but not systematically so in Chakdaha. Unlike Araihazar, there is also little correspondence in Chakdaha between dissolved As concentrations in groundwater and the P-extractable As content of aquifer particles, averaging 191 ± 122 ug As/L, 1.1 ± 1.5 mg As kg-1 (n = 43) and 108 ± 31 ug As/L, 3.1 ± 6.5 mg As kg-1 (n = 60), respectively. We tentatively attribute these differences to a combination of younger floodplain sediments, and therefore possibly more than one mechanism of As release, as well as less reducing conditions in Chakdaha compared to Araihazar. Conclusion Systematic dating of groundwater and sediment, combined with detailed mapping of the composition of aquifer solids and groundwater, will be needed to identify the various mechanisms underlying the complex distribution of As in aquifers of the Bengal Basin

A blood atlas of COVID-19 defines hallmarks of disease severity and specificity.

Treatment of severe COVID-19 is currently limited by clinical heterogeneity and incomplete description of specific immune biomarkers. We present here a comprehensive multi-omic blood atlas for patients with varying COVID-19 severity in an integrated comparison with influenza and sepsis patients versus healthy volunteers. We identify immune signatures and correlates of host response. Hallmarks of disease severity involved cells, their inflammatory mediators and networks, including progenitor cells and specific myeloid and lymphocyte subsets, features of the immune repertoire, acute phase response, metabolism, and coagulation. Persisting immune activation involving AP-1/p38MAPK was a specific feature of COVID-19. The plasma proteome enabled sub-phenotyping into patient clusters, predictive of severity and outcome. Systems-based integrative analyses including tensor and matrix decomposition of all modalities revealed feature groupings linked with severity and specificity compared to influenza and sepsis. Our approach and blood atlas will support future drug development, clinical trial design, and personalized medicine approaches for COVID-19

Non-institutionalised aged in Sydney, 1981

This study was designed to test hypotheses and develop population estimates regarding the social integration and social support of non-institutionalised people aged 60 and over living in Sydney. The core of the questionnaire aimed to identify the individuals who were important to respondents in terms of exchanges of instrumental assistance, emotional closeness, social interaction, and family structure: characteristics of these other persons were also recorded. Other variables included basic demographic and personal characteristics; various objective and subjective measures of functional health and illness; responsibility for household tasks; use of health and social services; knowledge of services: attitudes toward dependency and family relationships; use of time; housing and living arrangements; transport; retirement and income; life satisfaction; political views; and care of parents. Questions measured early life experiences, recent changes and current circumstances. Background variables include age; sex; marital status; bithplace; years of schooling; opccupation of self and spouse; religious affiliation; home ownership; and income level

Characterisation of organic matter in a shallow, reducing, arsenic-rich aquifer, West Bengal

Elevated arsenic in groundwaters extensively exploited for irrigation and drinking water in West Bengal and Bangladesh is causing serious impacts on human health. A key mechanism for the genesis of arsenic (As) in these waters is microbially mediated reductive transformation of arsenic-bearing Fe(III) hydrated oxides. The role of organic C in this process, whether from in situ organic matter (OM), i.e. OM from within the sediment, or from other sources, is widely recognised. Despite this, there is a paucity of data about the characteristics of OM in these As-rich aquifers. Extraction and analysis of the polar and apolar fractions from seven different sediments from a known groundwater As "hotspot" in West Bengal revealed OM characteristic of the original terrestrial depositional environment. However, this was overprinted by abundant hydrocarbons with thermally mature (e.g. petroleum) distributions. These hydrocarbons included abundant high molecular weight n-alkanes and unresolved complex mixtures (UCMs), as well as thermally mature distributions of hopanes and steranes. Additionally, at certain depths (surface sands: 8 and 13 m, deeper sands: 25 m) the OM appeared to be biodegraded, with the preferential removal of petroleum-sourced n-alkanes, suggesting that indigenous microbes within the aquifer can utilise this carbon source. The presence of this previously unreported source of bioavailable organic carbon is of importance as it has the potential to promote microbial activity and subsequent As release in the aquifers. © 2006 Elsevier Ltd. All rights reserved