Is the co-application of self-produced compost and natural zeolite interesting to reduce environmental and toxicological availability in metal-contaminated kitchen garden soils?

摘要

Composting can turn organic waste into a valuable soil amendment that can improve physi-cal,chemical,and biological soil quality.Compost amendments can also contribute to the remediation of areas anthropogenically degraded by metals.How-ever,it is well known that compost,particularly self-produced compost,can show enrichment in metals.An experimental study was conducted to examine the short-and long-term distribution and the mobil-ity of metals in soils amended with a self-produced compost when it was added alone or in combination with different doses of a natural zeolite to soil.The aim was also to study the interest of managing mod-erately metal-contaminated kitchen garden soils by assessing the chemical extractability,phytoavailabil-ity,and oral bioaccessibility of metals.When zeolite was added to compost alone,it had the tendency to better reduce extractability of Cd and Zn at 25％,and those of Pb at 15％.When the self-produced com-post alone or in co-application with zeolite at these doses was applied to soils,the results showed(1)adecrease of NH4NO3-extractable Zn;(2)a reduction of Pb environmental availability,but not Pb bioac-cessibility,and(3)an increase of ryegrass biomass.Nevertheless,the risk posed by the self-produced compost was minimal when applied at the proper rate(0.6％w/w).In the selected experimental conditions,the study recommends that self-produced compost be mixed with 15％zeolite to maximize vegetal bio-mass and minimize environmental risk.The question of sustainability of the results with repeated compost addition is also raised.