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Cities and contaminated areas can be primary or secondary sources of polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and other chemicals, into air and soil and can influence the regional level of some of these pollutants. In a contaminated site, the evaluation of such emissions can be crucial in the choice of the remediation technology to be adopted. In the city of Brescia (Northern Italy), more than 100 ha of agricultural areas were contaminated with PCBs, PCDD/Fs and heavy metals, originating from the activities of a former PCB factory. In order to evaluate the current emissions of PCBs and PCDD/Fs from the contaminated site, in a location where other current sources are present, we compared measured and predicted air concentrations, resulting from chemical volatilization from soils as well as fingerprints of Brescia soils and of soils contaminated by specific sources. The results confirm that the contaminated area is still a current and important secondary source of PCBs to the air, and to a lesser extent of PCDFs (especially the more volatile), but not for PCDDs. PCBs in soils have fingerprints similar to highly chlorinated mixtures, indicating contamination by these mixtures and/or a long weathering process. PCB 209 is also present at important levels. PCDD fingerprints in soil cannot be related to current emission sources, while PCDFs are compatible to industrial and municipal waste incineration, although weathering and/or natural attenuation may have played a role in modifying such soil fingerprints. Finally, we combined chemical and microbiological analyses to provide an integrated approach to evaluate soil fingerprints and their variation in a wider perspective, which accounts for the mutual effects between contamination and soil microbiota, a pivotal hint for addressing in situ bioremediation activities.

Abstract:The presence of emerging organic micropollutants (such as pharmaceuticals) in sewage has been, for a long time, an issue of great concern within the international scientific debate. This item represents one of the main challenges related to a sustainable development, with particular concern to the public health control. While most of the work has been concentrated on their detection and the evaluation of their average level, little is known about the spatial and temporal variability of concentrations of these compounds in the effluent and its capability to affect the concentrations in time of the receiving water body. In this study, three sampling campaigns were carried out at two different wastewater treatment plants (WWTPs) in Varese area (Northern Italy) with the aim of monitoring the occurrence of some pharmaceuticals to evaluate their removal efficiency. The detected pharmaceuticals were: Ofloxacin, Ibuprofen, Atenolol, Bezafibrate, Carbamazepine, Salbutamol, Cyclophosphamide and Hydrochlorothiazide. The results obtained, together with the analysis of the characteristics of the chemicals and of the two WWTPs, allowed evaluating the factors affecting the spatial and temporal concentration variability in effluent waters and the potential influence of this variability in driving the exposure of the aquatic ecosystems in the receiving water body.