title: Phytotoxicity and heavy metals speciation of stabilised sewage sludges.
abstract: The presence of heavy metals in the sludges produced in wastewater treatment restricts plants growth and hence their use for agricultural purposes. This study looks at different types of sludges (aerobic, anaerobic, unstabilised and sludge from a waste stabilisation pond) and compares the distribution of the heavy metals that they contain according to the treatment that they have undergone. The sewage sludges were subjected to chemical characterisation and phytotoxicity testing (in absence of substrate) to provide a preliminary assessment of their suitability for land application. In addition, the total quantity of metals (Cd, Cr, Cu, Ca, K, Fe, Mg, Ni, Na, Pb and Zn) was determined. The Community Bureau of Reference (BCR) method for heavy metal speciation was followed. It was confirmed that the total concentration of heavy metals did not exceed the limits set out by European legislation and that the stabilisation treatment undergone by the sludges strongly influenced the heavy metal distribution and the phases to which they were associated. The sludge extracts did not exert any significant adverse effect on the relative seed germination (RSG) of barley (Hordeum vulgare L.) or cress (Lepidium sativum L.), although the reduction in germination index (GI) indicates that some characteristics existed did have an adverse effect on root growth.
authors.affiliation: Department of Chemical Engineering, University of Murcia, Campus Espinardo, 30071 Murcia, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Fuentes
authors.forename: Mercedes
authors.initials: M
authors.lastname: Lloréns
authors.forename: José
authors.initials: J
authors.lastname: Sáez
authors.forename: Maria Isabel
authors.initials: MI
authors.lastname: Aguilar
authors.forename: Juan F
authors.initials: JF
authors.lastname: Ortuño
authors.forename: Victor F
authors.initials: VF
authors.lastname: Meseguer
mesh_terms: D001681:Biological Assay / Q000379:methods; D004784:Environmental Monitoring / Q000379:methods; D018525:Germination / Q000187:drug effects; D001467:Hordeum / Q000187:drug effects / Q000254:growth & development; D031220:Lepidium sativum / Q000187:drug effects / Q000254:growth & development; D019216:Metals, Heavy / Q000032:analysis* / Q000633:toxicity*; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D010944:Plants / Q000187:drug effects*; D012722:Sewage / Q000737:chemistry*
chemical_list: D019216:Metals, Heavy; D012722:Sewage