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Competitive sorption of cadmium and zinc in contrasting soils

Research output: Contribution to Journal/MagazineJournal articlepeer-review

  • Hui Ming
  • Ravi Naidu
  • Binoy Sarkar
  • Dane T. Lamb
  • Yanju Liu
  • Mallavarapu Megharaj
  • Donald Sparks
<mark>Journal publication date</mark>15/04/2016
Number of pages9
Pages (from-to)60-68
Publication StatusPublished
Early online date5/02/16
<mark>Original language</mark>English


The sorption behavior of cadmium (Cd(II)) and zinc (Zn(II)) on two virgin soils with different pH levels was studied using single metal and competitive dual metal systems. In the single metal system, Zn exhibited a greater affinity for the alkaline soil, as indicated by the Langmuir constant (KL = 8.85 L/kg) compared with Cd (KL = 1.79 L/kg). However, much less sorption of both Zn (KL = 0.19 L/kg) and Cd (KL = 0.07 L/kg) was observed in the acidic soil. The competitive sorption data were modeled using two-metal Freundlich and Langmuir functions. The competition for metal sorption occurred in the alkaline soil only at a higher concentration of the competing metals, whereas the effect was significant even at lower concentrations in the acidic soil. The cumulative amount of both metals sorbed in the soil was similar to that of single metal systems in the studied concentration range, demonstrating that the number of sites available for sorption remained constant irrespective of the competition. This study indicated that Cd might be more mobile in a mixed-metal system than in a single-metal scenario and thus poses a serious ecotoxicological threat. This study is important for assessing the risks and developing management strategies for multiple heavy metal contaminated soils.