Release of arsenic from metal oxide sorbents under simulated mature landfill conditions

•Non-redox sensitive sorbents leach arsenic to an equal or greater extent than a ferric sorbent.•Fe, Ti, Zr and La sorbents leach arsenic exceeding the Toxicity Characteristic.•Arsenic solid retention increases along a decreasing reduction activity gradient.•La retained a greater fractional proportion of its initial arsenic load than other sorbents due to a higher pHpzc.