Multi-Year Concentrations, Health Risk, and Source Identification, of Air Toxics in the Venice Lagoon

Abstract

This work presents and discusses the results of multi-year measurements of air toxics concentrations from different sites of Venice Lagoon. The aim of the study is the characterization of the air quality of the area, in terms of PM10, PM10-bound metals, and polycyclic aromatic hydrocarbons (PAHs) concentrations, even with the individuation of the related inhalation risk and the identification of the main contaminants’ sources. The study moreover provides an important multi-years trend of chemical characterization of the Venice Lagoon. Sampling for PM10 and its metal content was carried out between 2010 and 2015, using low volume sequential aerosol samplers; V, Cr, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Tl, and Pb were measured by ICP-MS. Samples for PAHs concentration in gas and particle phases were collected from 2010 to 2014, using a high-volume air sampler that allows to sample both phases simultaneously. Samples for PAHs determinations were analyzed by GC-HRMS. Concentrations of air toxics have been studied with the use of enrichment factor, the coefficient of divergence, and the Mann-Kendal test, to individuate eventual local divergences, seasonal and other temporal trends. The inhalation risk assessment has been achieved by the calculation of the cumulative incremental carcinogenic risk for all the air toxics analyzed. The sources’ identification and impact evaluation have been carried out using the atmospheric vanadium concentration, to calculate the primary contribution of ship traffic to PM10, the Positive Matrix Factorization, and the Diagnostic Ratios, with the aim of evaluating the impact of construction activities of M.o.S.E, (Modulo Sperimentale Elettromeccanico-Electromechanical Experimental Module) as well as of ship traffic and other possible air toxics’ sources. Temporal trends indicate a slight decrease of PAHs and PM10 and of its content of Pb, Zn, Sb. Sharp increases of As and Cd during 2014 and 2015 may be due to local sources like emissions from the construction yard, ship, and road traffic. The cumulative incremental carcinogenic risk was below the unconditionally acceptable risk; Co and As are the most important contributors among metals, followed by Cd and Ni while the PAH congeners that most contribute to the carcinogenic risk were benzo(a)pyrene and dibenzo(A,H)anthracene.