Riverine nitrate source identification combining δN/δO-NO with ΔO-NO and a nitrification N-enrichment factor in a drinking water source region.

Dual nitrate isotopes (δN/δO-NO) are an effective tool for tracing nitrate sources in freshwater systems worldwide. However, the initial δN/δO values of different nitrate sources might be altered by isotopic fractionation during nitrification, thereby limiting the efficiency of source apportionment results. This study integrated hydrochemical parameters, site-specific isotopic compositions of potential nitrate sources, multiple stable isotopes (δD/δO-HO, δN/δO-NO and ΔO-NO), soil incubation experiments assessing the nitrification N-enrichment factor (ε), and a Bayesian mixing model (MixSIAR) to reduce/eliminate the influence of N/O-fractionations on nitrate source apportionment.

Inward-to-outward assembly of amine-functionalized carbon dots and polydopamine to Shewanella oneidensis MR-1 for high-efficiency, microbial-photoreduction of Cr(VI).

A novel photosensitized living biohybrid was fabricated by inward-to-outward assembly of amine-functionalized carbon dots (NCDs) and polydopamine (PDA) to Shewanella oneidensis MR-1 and applied for high-efficiency, microbial-photoreduction of Cr(VI). Within a 72 h test period, biohybrids achieved a pronounced catalytic reduction capacity (100%) for 100 mg/L Cr(VI) under visible illumination, greatly surpassing the poor capacity (only 2.5%) displayed by the wild strain under dark conditions.

Nitrate pollution source apportionment, uncertainty and sensitivity analysis across a rural-urban river network based on δN/δO-NO isotopes and SIAR modeling.

Nitrate pollution is of considerable global concern as a threat to human health and aquatic ecosystems. Nowadays, δN/δO-NO combined with a Bayesian-based SIAR model are widely used to identify riverine nitrate sources. However, little is known regarding the effect of variations in pollution source isotopic composition on nitrate source contributions.