Potential harmful effects of landfill stabilized waste: semi-volatile organic compounds and salinity, a case study in Beijing, China

Landfill stabilized waste (LSW) is the aged municipal solid waste mined from old landfills. It is a soil-like material containing high value of organic matter and nutrients and thus may be used as topsoil substitute. To evaluate the potential harmful effects, LSW was sampled from five landfills around Beijing, China. The concentration of 150 semi-volatile organic compounds (SVOCs), total soluble salt, cation exchange capacity (CEC) and the distribution of water-stable aggregate size fractions were determined. According to the results, 14 SVOCs were detected in LSW, including phenol, cresol, 9 PAHs, 2 PAEs and 1 OCP. The concentrations of all detected SVOCs were below the critical limits for soil quality published by Chinese authority, but further studies are needed when it is applied in areas for residential use. The total soluble salt content of LSW ranged from 2.9 to 7.6 g kg⁻¹, and CEC ranged from 3.13 to 6.06 cmol kg⁻¹, indicating that LSW had a high level of salinity but a poor ability of holding and releasing positive-charged elements by clay minerals and humus colloids. Compared to agricultural soil (sandy clay), LSW had more and larger water-stable aggregates, and generally, plants grew better in LSW. LSW of 7–10 mm in size was best for plant growth. The results confirm LSW as a promising topsoil substitute which can be used in afforestation.