Unveiling HgS nanoparticle formation in Hg(II)-dissolved organic matter systems at low nanomolar to submicromolar levels: A comprehensive characterization via combined liquid chromatography-ICP-MS and single particle ICP-MS
Article
Chen, Y, Yang, P, Liu, G et al. (2026). Unveiling HgS nanoparticle formation in Hg(II)-dissolved organic matter systems at low nanomolar to submicromolar levels: A comprehensive characterization via combined liquid chromatography-ICP-MS and single particle ICP-MS
. JOURNAL OF HAZARDOUS MATERIALS, 514 10.1016/j.jhazmat.2026.142595
Chen, Y, Yang, P, Liu, G et al. (2026). Unveiling HgS nanoparticle formation in Hg(II)-dissolved organic matter systems at low nanomolar to submicromolar levels: A comprehensive characterization via combined liquid chromatography-ICP-MS and single particle ICP-MS
. JOURNAL OF HAZARDOUS MATERIALS, 514 10.1016/j.jhazmat.2026.142595
Formation of mercuric sulfide (HgS) via sulfidation plays a critical role in governing the environmental fate and transformation of mercury (Hg). Yet, the formation of HgS nanoparticles (HgSNP) from binary Hg(II)-dissolved organic matter (DOM) complexes in sulfide-depleted surrounding at environmentally relevant Hg levels remains poorly understood due to the limited sensitivity of conventional analytical methods. This study comprehensively identified and quantified the formation of HgSNP from binary Hg(II)-DOM complexes at Hg2 + concentrations ≤ 20 μg/L by combining ultrafiltration-transmission electron microscopy (TEM)-energy disperse spectroscopy, liquid chromatography (LC)-ICP-MS, and single particle (sp)-ICP-MS. After 90-day dark aging, TEM revealed a “flower-like” HgSNP (∼35–40 nm), consistent with size distributions obtained from LC-ICP-MS and sp-ICP-MS. Utilizing this highly sensitive methodology, HgSNP formation was detected even at 200 ng/L in Hg(II)-spiked environmental water. This HgSNP formation was strongly influenced by DOM characteristics (i.e., sulfur content, charge density, and molecular weight), pH, and Ca2+/Cl-. Elevated pH and Ca2+ increased HgSNP size, whereas Cl- suppressed particle growth, and oxygen exhibited negligible effects. Notably, both increased temperature and light irradiation markedly accelerated HgSNP generation. Critically, enriched isotope-tracing assays revealed that this specific aging pathway (partially as HgSNP) significantly suppressed microbial methylation potential (using Geobacter sulfurreducens), compared to newly input Hg2+. This work provides a robust comprehensive analytical approach for quantifying Hg(II)-DOM-derived HgSNP at trace Hg levels, and highlights the critical role of this sulfidation process in diminishing its bioavailability and ecological risk.
