title: The effect of sewage sludge application on soil properties and willow (Salix sp.) cultivation.
abstract: The aim of the study was to determine the impact of sewage sludge from three wastewater treatment plants of different sizes (small, medium and large) applied in two doses (3 and 9 tons per hectare) on soil properties, determined as the content of organic carbon and humus fractions, bacterial abundance, phytotoxicity and PCDD/PCDF TEQ concentrations. The study also evaluated the impact of this sewage sludge on the biometric and physiological parameters and detoxification reaction of willow (Salix sp.) as a typical crop used for the remediation of soil following sludge application. The cultivation of willow on soil treated with sludge was found to result in a gradual increase of humus fractions, total organic carbon content and bacterial abundance as well as soil properties measured using Lepidium sativum. However, it also produced an initial increase of soil phytotoxicity, indicated by Sinapis alba and Sorghum sacharatum, and PCDD/PCDF Toxic Equivalent (TEQ) concentrations, which then fell during the course of the experiment, particularly in areas planted by willow. Although the soil phytotoxicity and PCDD/PCDF TEQ content of the sewage sludge-amended soil initially increased, sludge application was found to have a positive influence on willow, probably due to its high nutrient and carbon content. The obtained results reveal increases in willow biomass, average leaf surface area and leaf length as well as chlorophyll a+b content. Moreover, a strong decline was found in the activity of the detoxifying enzyme glutathione S-transferase (GSTs), a multifunctional enzyme involved in the metabolism of xenobiotics in plants, again demonstrating the used sludge had a positive influence on willow performance.
authors.affiliation: European Regional Centre for Ecohydrology of the Polish Academy of Sciences, Lodz, Poland. Electronic address: m.urbaniak@unesco.lodz.pl.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Urbaniak
authors.affiliation: Department of Plant Physiology and Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Wyrwicka
authors.affiliation: Department of Soil Science and Geoecology, Faculty of Geography, University of Lodz, Lodz, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Tołoczko
authors.affiliation: European Regional Centre for Ecohydrology of the Polish Academy of Sciences, Lodz, Poland.
authors.forename: Liliana
authors.initials: L
authors.lastname: Serwecińska
authors.affiliation: Nofer Institute of Occupational Medicine, Lodz, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Zieliński
mesh_terms: D005308:Fertilizers; D032108:Salix / Q000254:growth & development*; D012722:Sewage; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D005308:Fertilizers; D012722:Sewage; D012987:Soil; D012989:Soil Pollutants
keywords: PCDDs/PCDFs; Phytotoxicity; Sewage sludge; Soil properties; Willow