Trends in arsenic, nickel and lead concentrations within particulate matter in Sao Paulo, Brazil

Background. Potentially Toxic Elements (PTE), such as arsenic, nickel, and lead in the atmospheric Particulate Matter (PM) is recognized as a serious concern to human health due to its potential to induce carcinogenic and non-carcinogenic effects. The vehicular traffic is the major environmental source to these pollutants in urban areas. This study aimed to analyze PTE concentrations trends in PM10, in Sao Paulo, Brazil. Methods. The dataset from the Environmental Agency of the State of Sao Paulo, composed by few air quality stations data, as part of specific studies of PTE concentrations, was analyzed. PTE concentrations were sampled in a place located near a congested avenue, throughout the years 2002, 2006, 2009, and 2012. PM samples were collected using a Dichotomous air sampler (47-mm diameter Teflon filter) and the elemental analysis was performed by energy dispersive X-ray fluorescence. Linear regression was applied to evaluate these trends and the t-Student test was used to verify the significance of the model. Result. Arsenic annual mean concentration indicated a downward trend ranging from 4.1 (2002) to 3.4 ng/m3 (2012). Lead also showed the same trend, ranging from 38.5 (2002) to 24.6 ng/m3 (2012). On the other hand, the Nickel did not show this trend, the values ranged from 7.6 (2002) to 10.2 ng/m3 (2012). The statistical analysis indicated significant correlations in winter/autumn seasons. Pearson’s correlations for Lead-Arsenic ranged from 0.79 to 0.87 (p<0.01) in the winter and autumn, respectively. Additionally, for Lead-Nickel these values ranged from 0.61 to 0.56 (p<0.01), while for As-Ni ranged from 0.47 to 0.57 for the same seasons (p<0.01). Conclusion. Our findings indicate that PTE concentrations are high and reinforce the importance of further studies on metals exposure and health risks of all population beyond the evaluation of public policies for risk management. Funding: CAPES, CNPq, FAPESP.