Tatiana Andreyeva, Xiaohan Sun
Universal School Meals in the US: What Can We Learn from the Community Eligibility Provision?
Nutrients
estimate risks developing remediation strategies mercury hgcontaminated soils crucial understand mechanisms hg transformation migration redoxchanging paddy fields present study hgspiked acidic paddy soil ph 452 incubated anoxic conditions 40 oxic conditions 20 anoxic incubation watersoluble exchangeable specifically adsorbed fulvic acidcomplexed hg decreased sharply whereas humic acidcomplexed hg organic sulfidebound hg gradually increased mainly ascribed enhanced adsorption surface soil minerals increase soil ph complexation organic matters precipitation hgs absorption soil colloids triggered reductive dissolution feiii oxides contrast oxygen introduced system gradual increase available hg occurred decreasing soil ph decomposition organic matters formation feiii oxides kinetic model established based key elementary reactions quantitatively estimate transformation processes hg fractions model matched well modified tessier sequential extraction data suggested large molecular organic matter humic acid dominated hg complexation immobilization acidic paddy soils content methylmercury increased reached peak anoxic 20 sulfatereducing bacteria desulfovibrio desulfomicrobium major hg methylating bacteria anoxic stage whereas demethylating microorganisms clostridiumsensustricto1 clostridiumsensustricto12 began grow oxygen introduced new dynamic results provided new insights exogenous hg transformation processes model could used predict hg availability periodically flooded acidic paddy fields