Heavy metal complexation in sludge‐amended soil. The role of organic matter in metal retention

Abstract

Soil columns which had received a range of applications of anaerobically digested sewage sludge were incubated for five months. The sludge application rates were equivalent to the one year average value and maximumvalue (equivalent to sixyears' addition) permittedby UK guidelines. About 23-26% of total organic matter degraded in the soil columns during incubation. Organically bound metals were extracted with pyrophosphate following incubation. Over half of the cadmium was in the organic phase, compared to less than 20% of the lead. The proportion of lead extractable was unaffected by the rate of sludge addition, whereas for copper percentage extractability decreased with increasing sludge application and for nickel and zinc percentage extractability increased. Organic complexes of copper and cadmium were stronger than for the other metals, and the binding capacity of the organic matter for metals was greatest for copper and nickel.

Implications of long term irrigation with wastewater on the contents and retention kinetics of potentially toxic elements in Typic Torripsamment soils

“…Cu and Cd (Lo et al, 2008). Similar results indicate that Zn (Kidd et al, 2007), Cu, Ni (Yin et al, 2002;Ashworth and Alloway, 2004;Kahapanagiotis et al, 2008), Pb and Cd (Weng et al, 2002;Gondar et al, 2006) were closely related with the soil content of organic matter. The obtained results also reveal that the soluble contents of the studied metals were significantly correlated with their total contents in soil.…”

Studies on land application of sewage sludge and its limiting factors

“…Sewage sludge is effective as a fertilizer, increases dry matter yield of many crops [8], and can also improve soil physical properties such as porosity, aggregate stability, bulk density, and water retention and movement [9]. Although raw sewage sludge contains valuable nutrients such as nitrogen, phosphorus, organic matter, and essential trace elements, it also contains various toxins, especially heavy metals, which cause harm to soil-plant system and further might pose a serious risk to human health [10,11].…”

Competitive adsorption of trace elements in calcareous soils as affected by sewage sludge, poultry manure, and municipal waste compost

“…Ashworth and Alloway (2004) observed very low Zn solubility and mobility, and relatively high Ni solubility and mobility, in sludge-amended soil columns of neutral pH. Other workers have also observed high Ni solubility in sludge-amended soil (Karapanagiotis et al 1991). The sorption of trace elements in calcareous soils was studied by Jalali and Moharrami (2007).…”