Characterization of risks to Atlantic Forest associated to air contamination by toxic elements, near an oil refinary, in Cubatão, São Paulo, with accumulator plants

Abstract

The portions of the Atlantic Forest that cover the slopes of Serra do Mar, in the region of Cubatão, have been affected by air pollutants such as sulfur and nitrogen dioxides and particulate material (NOx, SOx and PM, respectively). The air contamination is a result of the pollutant emissions from several industries installed in the region, with diverse kinds of activity. In particular, the oil refinery locally known as Refinaria Presidente Bernardes contributes significantly to the mentioned emissions due to the combustion of oil in boilers for energy and vapor generation. Such system will be substituted by a system technologically modern (thermoelectric plant moved by natural gas), which will theoretically result in a reduction of the levels of air contamination around the refinery, mainly by NOx, SOx and PM, where the Atlantic Forest occurs. As a consequence, it is plausible to assume that the risks imposed by air pollutants to the forest will decrease and that such environmental change may be biologically detected by Lolium multiflorum ssp. italicum cv. Lema, Tibouchina pulchra Cogn. and/or Psidium guajava 'Paluma', which are recognized accumulator plants of toxic elements contained in the mentioned air pollutants (nitrogen, sulfur and heavy metals), taking into consideration the results of previous studies developed there. Therefore, a biomonitoring program has been performed in the region over a period between the phases of burning oil in boilers and of routine operation of the new system for energy and vapor generation. The project was redesigned to doctorate and aims: to identify which species, among those mentioned before, has the greatest accumulator potential and is more suitable for biomonitoring in the region; to assess whether the biological hazards associated with sulfur, nitrogen and heavy metals in the vicinity of the oil refinery will decrease after the exchange of system of power generation, by using the species with the greatest accumulator potential and to check whether the change in the profile of air pollution will result in lower risks imposed by toxic elements to the Atlantic Forest. The study will have three experimental steps: choice of the most appropriate accumulator species (carried out from April/2009 to February/2010); studies in open-top chambers with unfiltered and filtered air (July/2010 to March/2012) and long-term biomonitoring for identifying possible changes in the profile of air pollution (April/2009 to July 2012). The experimental field steps will be held within seven points distributed in the vicinity of the refinery and close to the Serra do Mar, and in an eighth point in a region less affected by pollutants from the industrial area. The studies in the open-top chambers will occur only in one of these points. During all the experimental steps, lots of different plants of L. multiflorum will remain in the field sites for 28 days and of T. pulchra and P. guajava for 84 days. The leaf concentrations of nitrogen (Kjeldahl method), sulfur (turbidimetric method) and heavy metals (optical emission spectrometry with inductively coupled plasma) will be determined at the end of each period. After defining the most suitable species, the biomonitoring will continue only with this species. Analysis of variance followed by multiple comparison test will be performed to identify differences among treatments (periods, sites and/or accumulator species under field conditions or in open-top chambers. Multivariate analysis will be carried out to determine the relationship between the variations in the leaf concentrations of chemical elements and oscilations on the environmental conditions (climate and concentrations of pollutants in the atmosphere). (AU)