Evaluation of urban tree barks as bioindicators of environmental pollution using the X-ray fluorescence technique.

Some chemical elements released in nature due to anthropogenic actions are harmful to living beings, and finding efficient and low-cost ways to measure their presence is a challenge. The major goal of this work was to use the barks of urban trees as bioindicators of the presence of these elements. For this purpose, tree barks of sixteen individual trees were collected, including Ipê (Bignoniaceae Family); Sibipiruna (Fabaceae Family); Pine (Pinaceae Family), in the city of Sorocaba, SP, Brazil, in three different districts.