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 kettles for energy and vapor production. 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 recognized accumulator plants of toxic elements contained in the mentioned air pollutants (nitrogen, sulfur and heavy metals), taking into consideration results of previous studies developed there. Therefore, a biomonitoring program will be performed in the region over a period that includes the present situation and the future situation in which the new system of energy and vapor production will be routinely operated. The present project aims at to evaluate if the biological risks imposed by N and S contained in the gaseous e/or particulate pollutants and by heavy metals adsorbed in the particulate material will alter in function of the exchange of the system of energy and vapor production. Plants of Lolium multiflorum ssp. italicum cv. Lema, Tibouchina pulchra Cogn. and Psidium guajava 'Paluma', which are known accumulator plants of N, S, Al, Zn, Cu, Fe, Pb, Cd , Ni, among other toxic elements, will be continuously exposed during two years in 7 sites distributed around the refinery and next to the slopes of Serra do Mar and in an eighth site less affected by air pollutants from the industrial complex (Pilões river valley). The exposure period will be initiated before the start of the thermoelectric plant. New lots of plants of L. multiflorum will be introduced in each site every 28 days and T. pulchra and P. guajava every 84 days. The leaf concentrations of the mentioned toxic elements will be determined at the end of such exposure periods. These field studies will be complemented with semi-controlled experiments developed at that same region, in which the plants will be exposed in parallel to the natural contaminated air and to filtered air in open top chambers, aiming at determining more precisely the biological risks associated with the air contaminants of interest. At the end of the present project, the most suitable accumulator plant for biomonitoring air contamination in the region may also be indicated.