The analysis of heavy metal concentrations and forms in sewage sludge constitutes an important issue in terms of both health and environmental hazards the metals pose. The total heavy metals concentration enables only the assessment of its contamination. Hence the knowledge of chemical forms is required to determine their environmental mobility and sludge final disposal. Heavy metals speciation was studied by using four-stage sequential extraction BCR (Community Bureau of Reference). This study was aimed at determining the total concentration of selected heavy metals (Zn, Cu, Ni, Pb, Cd, Cr and Hg) and their chemical forms (except for Hg) in sludge collected at different stages of its processing at two municipal Wastewater Treatment Plants in southern Poland. Metals contents in sludge samples were determined by using flame atomic absorption spectrometry (FAAS) and electrothermal atomic absorption spectrometry (ETAAS). This study shows that Zn and Cu appeared to be the most abundant in sludge, while Cd and Hg were in the lowest concentrations. The sewage sludge revealed the domination of immobile fractions over the mobile ones. The oxidizable and residual forms were dominant for all the heavy metals. There was also a significant difference in metals speciation between sludges of different origin which was probably due to differences in wastewater composition and processes occurring in biological stage of wastewater treatment. The results indicate a negligible capability of metals to migrate from sludge into the environment. Our research revealed a significant impact of thickening, stabilization and hygienization on the distribution of heavy metals in sludge and their mobility.

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Lung cancer is the leading cause of cancer occurrence around the world. When exploring the geographic distribution in lung cancer incidence in Poland, we found that PM 10 -bound benzo(a)pyrene (B(a)P) emission from domestic heating contributes to lung cancer risk mostly in areas outside the cities and agglomerations (so-called remaining areas). When averaging B(a)P concentrations within provinces, the B(a)P exposure accounts for even 31% to the total lung cancer cases. To check to which extent the concentration of B(a)P could contribute to an increase probability of lung cancer occurrence, the analysis of health risk was performed. The B(a)P concentration data were downloaded from the Polish Chief Inspectorate of Environmental Protection (CIEP) database. Those concerned the period between 2010 and 2015 and included cities, agglomerations, typically rural sites, and the remaining areas. It was found that the mean concentration of B(a)P in the mentioned period, averaged within specific geographic areas, varied from 1.39 ng/m 3 at the rural sites to 4.86 ng/m 3 in the remaining areas. The inhalation lung cancer risk resulting from the life-long exposure to B(a)P in most conservative (pessimistic) scenario was above the acceptable limits, i.e., E-06. On average, the highest lung cancer risk was found in Opolskie (7.33E-04) and the lowest one in Lubelskie province (1.02E-04), while in the rural areas one order of magnitude lower and amounted to (E-05). Presented results indicate the need for further research on geographic patterns of lung cancer incidence in Poland due to regional differences in air pollution. Such information could be further used for planning long-term strategies to reduce the ambient concentrations of B(a)P.