Correlation of Oxidative Potential with Ecotoxicological and Cytotoxicological Potential of PM₁₀ at an Urban Background Site in Italy

Exposure to atmospheric particulate matter (PM) has detrimental effects on health, but specific mechanisms of toxicity are still not fully understood. In recent years, there has been a growing evidence that oxidative stress is an important mechanism of toxicity; however, when acellular oxidative potential (OP) data are correlated with the outcomes of in vitro (or in vivo) toxicological tests there are contrasting results. In this work, an analysis of PM₁₀ health effect indicators was done, using the acellular Dithiotreitol (DTT) assay to retrieve OP^DTT, the Microtox^® test on Vibrio fischeri bacterium to assess the ecotoxicological potential, and the in vitro MTT assay on the human cell line A549 to estimate the cytotoxicological potential. The objective was to evaluate the correlation among acellular OP^DTT and the results from toxicological and ecotoxicological bioassays and how these health-related indicators are correlated with atmospheric PM₁₀ concentrations collected at an urban background site in Southern Italy. Results indicated that both bioassays showed time-dependent and dose-dependent outcomes. Some samples presented significant ecotoxic and cytotoxic response and the correlation with PM₁₀ concentration was limited suggesting that these health endpoints depend on PM₁₀ chemical composition and not only on exposure concentrations. OP^DTT showed a statistically significant correlation with PM₁₀ concentrations. MTT and Microtox outcomes were not correlated suggesting that the two toxicological indicators are sensitive to different physical-chemical properties of PM₁₀. Intrinsic oxidative potential OP^DTT_M (DTT activity normalised with PM₁₀ mass) was correlated with mortality observed with MTT test (normalized with PM₁₀ mass); however, it was not correlated with Microtox outcomes. View Full-Text