Biosolids and Biosolids-ash as Sources of Heavy Metals in a Plant-Soil System

摘要: Generally, the potential for biosolids (digested or composted)to contribute heavy metals to soil-plant system has beencompared with commercial fertilizers and other organic wastesbut not biosolids-ash. An column study was conducted in agreenhouse determine availability, extractability andleachability of a degraded, non-calcareous soilamended different (200 Mg ha-1). Thebiosolids investigated were dewatered, anaerobically digestedbiosolids, composted The columns(26 cm) planted wheat (Triticum aestivum L. cvMexa). addition digested decreased drymatter yield wheat. Treatments including biosolidsincreased Cu Zn concentrations roots, straw andgrain, whereas biosolids-ash did affect theconcentrations these Concentrations Ni,Co, Pb, Cr Cd below reliable detection limits(0.06, 0.05, 0.1, 0.06 0.02 mg kg-1, respectively).After harvesting, total AB-DTPA extractable Cu, Pbincreased upper layer soil amended thedifferent studied, levels AB-DTPAextractable Ni Co affected only when wasamended biosolids. Total chromiumincreased treatments TheAB-DTPA Pb lower thesoil evidenced downwardmovement metals. However, absence incolumn leachates indicates that this movement gradual.