An evaluation of the modified BCR sequential extraction procedure to assess the potential mobility of copper and zinc in MSW

Copper and zinc were determined in municipal solid waste (MSW) samples with different deposit ages from Tianziling landfill site. The pseudototal metal contents of the MSW samples were determined following an aqua regia digestion. Operational speciation was performed using the modified BCR sequential extraction procedure. Analyses were carried out by AAS. Agreement between most of triplicate samples was acceptable. The amount of copper and zinc extracted in the sequential procedure (i.e. Step 1, Step 2, Step 3, residual) did not generally agree well with pseudototal digestion. Various MSW samples contained significant different levels of copper and zinc, but these were with different potential migrations. For example, 49.88%-76.34% of copper existed in five MSW samples was present as oxidable fraction while ~ 40% of zinc was present as acid soluble fraction. The study illustrates the feasibility and importance of modified BCR sequential extraction procedure used as evaluation method when assessing the potential mobility of heavy metal in MSW landfill.