Sources, dispersion and toxicity of PAHs and dioxins at AUB, Zouk and Dora -

Abstract

There are two families of toxic air pollutants; polycyclic aromatic hydrocarbons (PAHs) and polychlorinated dibenzo-p-dioxins and and dibenzofurans PCDD-Fs, for which assessment and characterization in the atmosphere need to be considered. Polycyclic aromatic hydrocarbons (PAHs) in the atmosphere originate from biogenic sources, such as forest fires and volcanic eruption. However, their presence in populated urban areas is influenced by anthropogenic emissions, such as domestic and industrial activities as well as gasoline and diesel combustion. Persistent organic pollutants (POPs) are semivolatile compounds associated to particulate matter and include polychlorinated dibenzo-p-dioxins and and dibenzofurans PCDD-Fs, so called “Dioxins”. PCDD-Fs have been reported to be carcinogenic and mutagenic possessing toxicities towards human health. They are released from the incomplete combustion of chlorinated species and incinerators. The chaotic unregulated emission from the aforementioned sources has led us to conduct a systematic measurement and assessment of PAHs and PCDD-Fs in three representative sites (AUB, Zouk and Dora) of Beirut and its suburbans. Particulate and gaseous phase PAHs and Dioxins were collected using a high volume sampler (HVS) equipped with both quartz fiber filter and polyurethane foam (PUF). Following, thorough and careful extraction and quantification approaches were followed according to international and locally developed standard operation procedures (SOPs). Results showed spatial variations in the levels of PAHs and dioxins at AUB, Zouk and Dora. The lowest concentrations of these chemicals were registered at AUB. Higher amounts were found in Zouk, but the most toxic levels were in Dora. Strong seasonal variations were observed among PAH levels. Light PAH concentrations were always higher during the winter, whereas heavy congeners amounts were relatively higher in the summer. These sources were apportioned using PMF. Investigations showed that diesel, gasoline and heavy fue