Arsenic redox disequilibrium in geogenic contaminated groundwater: Bioenergetic insights from organic molecular characterization and gene-informed modeling.

Biotransformation of arsenic (As) influences its speciation and mobility, obscuring mechanistic comprehension on spatiotemporal variation of As concentration in geogenic contaminated groundwater. In particular, unresolved processes underlying As redox disequilibrium in comparison to major redox couples discourage practical efforts to rehabilitate the As-contaminated groundwater. Here, quantitative metagenomic sequencing and ultrahigh-resolution mass spectrometry (FT-ICR-MS) were jointly applied to reveal the links between vertical distribution of As metabolic gene assemblages and that of free energy density of dissolved organic matter (DOM) in As-contaminated groundwater of Datong Basin.

Arsenic biogeochemical cycling association with basin-scale dynamics of microbial functionality and organic matter molecular composition.

Geogenic arsenic (As)-contaminated groundwater is a sustaining global health concern that is tightly constrained by multiple interrelated biogeochemical processes. However, a complete spectrum of the biogeochemical network of high-As groundwater remains to be established, concurrently neglecting systematic zonation of groundwater biogeochemistry on the regional scale. We uncovered the geomicrobial interaction network governing As biogeochemical pathways by merging in-field hydrogeochemical monitoring, metagenomic analyses, and ultrahigh resolution mass spectrometry (FT-ICR MS) characterization of dissolved organic matter.

Effect of amendments on soil Cd sorption and trophic transfer of Cd and mineral nutrition along the food chain.

Phytotoxicity of cadmium (Cd) and its trophic transfer along a terrestrial food chain have been extensively investigated. However, few studies focused on the role of amendments on the trophic transfer of Cd and related mineral nutrients. In a 60-day pot experiment, soil Cd availability, accumulation of Cd, mineral nutrients (Ca and Si) in lettuce, and subsequent trophic transfer along the lettuce-snail system were investigated with or without 3% (w/w) soil amendment (biochar or micro-hydroxyapatite, μHAP).