ASSESSMENT OF POLYCYCLIC AROMATIC HYDROCARBONS URBAN AIR POLLUTION USING THUJA OCCIDENTALIS.

Polycyclic aromatic hydrocarbons (PAH) are a generally hazardous class of organic compounds being ubiquitous environmental pollutants originating from both natural and anthropic sources. Combustion processes are major sources of their presence in atmospheric aerosols. According to their origin, PAH compounds that are present in environment are classified in two major groups: pyrolitic and petrogenic. Due to their toxic, mutagenic and carcinogenic potentials PAH compounds are associated with health hazardous effects and are included in the list of priority pollutants of US EPA, and European Union. The purpose of the present study is to monitor PAHs air pollution in Cluj-Napoca, 350,000 inhabitants, Romania, using PAH atmospheric deposition on Thuja occidentalis leaves. Five representative monitoring points located in urban, suburban, heavy traffic and residential areas were selected. Total content of ten PAHs, selected as representative, on the Thuja leaves was then determined. Separation of the compounds of interest was performed by ultrasound assisted extraction and PAHs were determined by High Performance Liquid Chromatography. The results showed variations of PAHs content in Thuja leaves that can be correlated with the location of sampling point. The measured values were situated between 58.45 - 537.74 ng/g total PAHs in dry leaves, with maximum concentrations in zones with high traffic and lowest concentration in suburban zone. In order to identify the sources of pollution, ratios of selected PAH compounds such as the abundance ratio of 2-3-ring hydrocarbons to 4-6 ring hydrocarbons (ΣLMW/ΣHMW), abundance ratio of combustion resulted PAHs to total PAHs (ΣCOMB/ΣTotalPAH), isomeric ratios of Anthracene/(Anthracene + Phenanthrene), Fluoranthene/(Fluoranthene + Pyrene), Benzo[a]anthracene/(Benzo[a]anthracene + Chrysen), Pyrene/(Benzo[a]pyrene) were used. The results suggest that the sources of PAH are pyrolitic and generated by combustion engines. [ABSTRACT FROM AUTHOR]