A preliminary characterization of the mutagenicity of atmospheric particulate matter collected during sugar cane harvesting using the Salmonella/microsome microsuspension assay

Abstract

During sugar cane harvesting season, which occurs from May to November of each year, the crops are burnt, cut, and transported to the mills. There are reports showing that mutagenic activity and PAH content increase during harvesting season in some areas of São Paulo State in comparison with nonharvesting periods. The objective of this work was to preliminarily characterize the mutagenic activity of the total organic extracts as well as corresponding organic fractions of airborne particulate matter (PM) collected twice from two cities, Araraquara (ARQ) and Piracicaba (PRB), during sugar cane harvesting season using the Salmonella/microsome microssuspension assay. One sample collected in São Paulo metropolitan area was also included. The mutagenicity of the total extracts ranged from 55 to 320 revertants per cubic meter without the addition of S9 and from not detected to 57 revertants per cubic meter in the presence of S9 in areas with sugar cane plantations. Of the three fractions analyzed, the most polar ones (nitro and oxy) were the most potent. A comparison of the response of TA98 with YG1041 and the increased potencies without S9 indicated that nitro compounds are causing the observed effect. More studies are necessary to verify the sources of the mutagenic activity such as burning of vegetal biomass and combustion of heavy duty vehicles used to transport the sugar cane to the mills. The Salmonella/microsome assay can be an important tool to monitor the atmosphere for mutagenicity during sugar cane harvesting season.

Genotoxicity of Polycyclic Aromatic Hydrocarbons and Nitro-Derived in Respirable Airborne Particulate Matter Collected from Urban Areas of Rio de Janeiro (Brazil)

“…The presence of dinitroarenes was detected at site 1 (September and October), 2 (August and October), and 3 (September and October). It is well known that when nitrocompounds are implicated, the mutagenic response in the presence of S9 mix is decreased compared to the situations without S9 mix [8, 11]. This is because mammalian enzymes reduce nitroarenes all the way to arylamines, and arylamines are not direct-aging mutagens.…”

“…According to [8], the mutagenicity of airborne particulate can result from at least 500 identified compounds from various chemical classes. Mutagenic nonsubstituted PAHs are the most studied and well-known compounds; however, more recently, nitro- and oxy-PAHs have been shown to be very important because of their strong biological activity [9–11]. …”

“…The use of strains of Salmonella typhimurium with different metabolic capacities can indicate the class or classes of compounds present in an environmental sample [11–13]. …”

Comparison of the sensitivity of strains of Salmonella enterica serovar Typhimurium in the detection of mutagenicity induced by nitroarenes

“…The use of strains of Salmonella enterica serovar Typhimurium with different metabolic capacities can indicate the class or classes of compounds present in an environmental sample (DeMarini et al, 2004;de Aragão Umbuzeiro et al, 2008). The Salmonella/microsome assay identifies the presence of organic compounds and enables diagnosis of the mutagenic activity of these pollutants adsorbed on particulate matter (PM) in the air.…”

“…The contributions of nitroarenes to direct mutagenic activity are commonly investigated through the Salmonella/microsome assay with the following S. enterica serovar Typhimurium strains: TA98 (frameshift strain) and the derivative strains TA98/1.8-DNP 6 (O-acetyltransferase-deficient), TA98NR (nitroreductase-deficient) (Rosenkranz and Mermelstein, 1980), YG1021 (nitroreductase-overproducing), and YG1024 (O-acetyltransferase-overproducing) (Watanabe et al, 1989(Watanabe et al, , 1990. Genotoxic evaluation studies of particulate matter using these strains have been conducted previously (Sato et al, 1995;Vargas et al, 1998;Ducatti and Vargas, 2003;de Aragão Umbuzeiro et al, 2008;Coronas et al, 2009;Pereira et al, 2010;Rainho et al, 2012Rainho et al, , 2013a.…”