The environmental monitoring of air pollution in the Santa Cruz industrial district of Rio de Janeiro using a plant fertility model.

In 2010, a steel company was established in Santa Cruz, Rio de Janeiro. In 2012, silver rain raised concerns about human and environmental impacts. In 2013, the steel company signed an Adjustment of Conduct Term (ACT). To evaluate air pollution in the vicinity of the steel company based on a plant fertility assay before and after ACT implementation. A pollen abortion assay was implemented using flower buds of Bauhinia forficata in 2013 and Delonix regia in 2015. Sites over 5 km from the steel company, highways, and tunnels were classified as unexposed; sites 5 km from highway/tunnel were classified as exposed to other sources; and sites 5 km from the steel company were classified as exposed. Random plant collection occurred during the dry and rainy seasons (10 buds/site and 300 cells/slide). Aborted grains were analyzed using a 400-fold magnification microscope. Statistical analyses were considered significant at the 5% level. In 2013 were collected flower buds in 27 sites (2 unexposed, 18 highway/tunnel-exposed, and 7 steel company-exposed); and 34 sites in 2015 (14 unexposed, 18highway/tunnel-exposed, and 2 steel company-exposed). In both years, the mean pollen abortion was significantly higher in the dry season for sites exposed to highway/tunnel (p < 0.001) and the steel company (p = 0.005). In 2013, the mean pollen abortion was significantly higher in sites exposed to highway/tunnel compared to unexposed sites (p = 0.004) and in sites exposed to the steel company compared to sites exposed to highway/tunnel (p = 0.034). In 2015, compared to unexposed sites, the mean pollen abortion was significantly higher in sites exposed to highway/tunnel (p = 0.014) and the steel company (p < 0.001). Overall, compared to unexposed sites, the mean pollen abortion was 5.79-fold higher in sites exposed to the steel company and 4.08-fold higher in sites exposed to highway/tunnel. Compared to unexposed plants, greater air pollution effects occurred in plants exposed to the steel company before (2013) and after (2015)ACT implementation.