Chemical and microbial characterization of indigenous topsoil and mosses in green urban areas of Rome

Abstract Sources of potential contamination for an urban soil are basically due to atmospheric fallout of pollutants produced by domestic heating system and vehicular traffic. Taking into account the recent use of catalytic converters, persistent inorganic micropollutants like Platinum Group Elements (PGEs) must be added. The present research is based upon the use of natural matrices (indigenous mosses and topsoil) to study the distribution of concentration of the following inorganic pollutants: Al, Cd, Cr, Cu, Hg, Ni, Pb, V, Zn and PGEs (Pt, Pd, Rh). Determination of such element has been performed by different instrumental spectroscopy techniques, in particular HR-ICP-MS for PGEs and ICP-AES and ETAAS for the other elements. Microbial parameter such as Actinomycetes, Moulds and Total Bacterial Count at 22 °C have been surveyed in mosses as well, due to their high sensitivity to low loads of pollutants. Urban areas in the city of Rome monitored during investigation have been Villa Borghese, Villa Ada and Villa Doria Pamphili. Eleven stations have been set up altogether. Two more spots (Villa Celimontana and National Institute of Health's gardens) have been investigated to get a more complete survey of the entire area. The aim of this study is to provide data set on levels of inorganic traffic-related micropollutants present in urban soil, supporting the use of indigenous mosses as passive biomonitors, and compare such data with those from other Italian cities. An estimation of time-depending changing of PGEs concentration in natural matrices is provided as well.