Differentiating natural organic matter roles in freshwater floc and bed sediment lead dynamics

Natural organic matter (NOM) is shown to be an important determinant of Pb dynamics across nine highly variable freshwater (wetland, stream, lake) ecosystems of Ontario, Canada. Soluble organic–Pb complexes emerged as the dominant Pb aqueous species (68–99%) in NOM-rich ecosystems; while distinct surficial sediment and suspended floc Pb sequestration and solid-solution partitioning patterns were observed across sites, driven by differential …