engleski

Modeling soil mobility of Cu and Cd originating from urban waste compost using HYDRUS-2D

Urban waste composts may contain trace metals and the estimation of their mobility in soils after the compost application is an important approach for monitoring the quality of the amended soils. Thus, the objective was to simulate Cu and Cd leaching from the compost amended soils by using HYDRUS-2D numerical modeling. Two experimental plots amended with a co-compost of sewage sludge and green wastes (SGW) or with a municipal solid waste compost (MSW) were compared to a control plot (CONT). Two sorption estimation approaches were used: either assuming the equilibrium between CaCl2 and EDTA extractable metals (Kd-1), or using the equations based on pedotransfer functions assuming nonlinear sorption for Cu (Kf) and a linear sorption for Cd (Kd-2). Cu lysimeter data were successfully reproduced with the Kd-1 approach for the SGW and CONT plots (model efficiency coefficient ESGW=0.97, ECONT=0.95), while the MSW plot showed better fitting with the Kf approach (EMSW=0.77), possibly because of the less stable organic matter in the MSW compost. The Cd leaching was reproduced with the Kd-2 approach for the two amended plots (ESGW=0.12, EMSW=0.80), while the CONT plot fluxes were poorly simulated (ECONT=−29.52), probably due to the overestimation of the low pH and organic carbon effect on Kd-2(Cd). The mobility of both, Cu and Cd appeared to be quite low in the tilled layer, suggesting that the organic matter and added compost sorption capacity had a major role for their soil mobility.

soil quality, compost amedmends, trace metals leaching, numerical simulations

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