Characterization and biotoxicity of landfill leachate and concentrates from controlled municipal solid waste landfills

Landfill leachate and concentrates from nanofiltration (NF) and reverse osmosis (RO) processes pose potential environmental threats. This study investigates the seasonal variations in the physicochemical properties and acute toxicity of landfill leachate and concentrates from Shenyang, Liaoning, China. The hydrophilic matter (HyI) constituted the major component of dissolved organic matter (DOM) in landfill leachate (68.18% on average). Humic substances were enriched in NF and RO concentrates, accounting for 86.92 and 62.78%, respectively. Landfill leachate exhibited strong toxicity to <i>Artemia salina</i>, particularly in summer. Although biotreatment processes reduced toxicity, the concentrates remained toxic. Principal component analysis (PCA) revealed significant correlations between physicochemical variables and toxicity. Discriminant analysis indicated that certain variables could predict acute toxicity. This study highlights the need for effective management of landfill leachate and concentrates on mitigating environmental risks.