| dc.description | Although air pollution decreased in some cities that shifted from an industrial to a service-based
economy, and vehicular emission regulation became more restrictive, it is still a major risk factor for
mortality worldwide. In central S~ao Paulo, Brazil, air quality monitoring stations and tree-ring analyses
revealed a decreasing trend in the concentrations of particulate matter and metals. Such trends, however,
may not be observed in industrial districts located in the urban periphery, where the usual mobile
sources may be combined with local stationary sources. To evaluate environmental pollution in an industrial
district in southeastern S~ao Paulo, we assessed its spatial variability, by measuring magnetic
properties and concentrations of Al, Ba, Ca, Cl, Cu, Fe, K, Mg, Mn, P, S, Sr, Zn in the bark of 62 trees, and its
temporal trends, by measuring Cd, Cu, Ni, Pb, V, Zn in tree rings of three trees. Source apportionment
analysis based on tree barks revealed two clusters with high concentrations of metals, one related to
vehicular and industrial emissions (Al, Ba, Cu, Fe, Zn) in the east side of the industrial cluster, and the
other related to soil resuspension (Cu, Zn, Mn) in its west side. These patterns are also supported by the
magnetic properties of bark associated with iron oxides and titanium-iron alloy concentrations. Dendrochemical
analyses revealed that only the concentrations of Pb consistently decreased over the last
four decades. The concentrations of Cd, Cu, Ni, V, and Zn did not significantly decrease over time, in
contrast with their negative trends previously reported in central S~ao Paulo. This combined biomonitoring
approach revealed spatial clusters of metal concentration in the vicinity of this industrial
cluster and showed that the local population has not benefited from the decreasing polluting metal
concentrations in the last decades. | |
