Integrated study of genotoxicity biomarkers in schoolchildren and inhalable particles in areas under petrochemical influence.

This study aimed to evaluate genotoxicity effects of inhalable particulate matter from areas influenced by a petrochemical complex on exposed children population. Peripheral blood and buccal mucosa exfoliated cells were collected from 54 children (5-12 years) at two public schools, 2.5 Km (Site NW) and 35 km (Site NWII) from the main industrial emission source. These areas lie in the first wind direction from a petrochemical complex. Blood samples were used to Comet Assay (CA) evaluating the tail intensity and to the cytokinesis-block micronucleus cytome assay (CBMN-cyt), assessing the frequency of micronucleus (MN), nuclear buds (NBUDs) and nucleoplasmic bridges (NPBs). Buccal micronucleus cytome assay (BMCyt) was used to detect MN and nuclear abnormalities. Mutagenicity of particulate matter (PM) organic extracts from these two sites, besides from one in the second wind direction (NE) was evaluated by Salmonella/microsome assay, microsuspension method, strains TA98, YG1021 and YG1024 with and without metabolic activation (S9). The site closest to the petrochemical complex (NW) presented worse air quality, evidenced by greater PM mutagenicity and more toxic PAHs profile (ΣTEQ). Also, Tail intensity was significantly higher at this site (10.65 ± 0.78) compared to site NWII (6.73 ± 0.92). MN frequencies in CBMN-cyt did not differ among groups, but was significantly higher than an external reference site. NBUDs were significantly higher at site NWII. BMCyt showed no difference among the groups for MNs and NBUDs. Site NWII showed higher frequencies of karyorrhexis and karyolysis. All samples, even within the PM limits, presented genotoxic potential. Results showed that the children are exposed to a mixture of contaminants from different sources, and that the proximity of the petrochemical industry gives a cause of concern. Actions must be taken to identify and reduce emissions and hazardous effects, since air quality standards are not enough to ensure the exposed population health.

Soil mutagenicity - Effects of acidification and organic pollutants in urban/industrial areas.

This study aimed to analyze (i) the effect of different acid extractions, simulating changes in the background pH of rain on the availability of soil mutagenic compounds, (ii) the presence of organic compounds in soil and (iii) evaluation of the effects of soil sieving on the samples mutagenicity. Surface soil samples were collected at urban and industrial areas and assessed as total grain size composition (Total Soil) and in sieved fraction <0.5 mm (Soil <0.5 mm), through acid extracts with pH simulating those found in local rainfall. Metals were quantified in extracts and soils in natura. Organic extracts were analyzed for PAH content. Salmonella/microsome mutagenicity assay (TA98 strain) was used, in the presence/absence of exogenous metabolism. Nitro-sensitive strains YG1021 and YG1024 were used in the organic extracts. Results showed different mutagenic responses in total soils and in soil <0.5 mm. Soil extraction at pH 3.6 presented higher toxicity, greater variety and concentration of metals. Extraction at pH 5.3 improved mutagenic detection. Thus, local rainfall may be an environmental contamination route, with additional risk of releasing toxic substances during acid precipitation events.

Genotoxicity biomarkers for airborne particulate matter (PM2.5) in an area under petrochemical influence.

The effects of fine inhalable particles (PM2.5) were evaluated in an area under the influence of a petrochemical industry, investigating the sensitivity of different genotoxicity biomarkers. Organic extracts were obtained from PM2.5 samples at two sites, positioned in the first and second preferential wind direction in the area. The extracts were evaluated with Salmonella/microsome assay, microsuspension method, strains TA98, YG1021 and YG1024. The mammalian metabolization fraction (S9) was used to evaluate metabolite mutagenicity. The Comet Assay (CA) and Micronuclei Test were used in a Chinese hamster lung cell line (V79). All extracts showed mutagenicity in Salmonella, and nitrogenated compounds were strongly present. Genotoxicity were found in CA in almost all extracts and the micronuclei induction at the Site in the first (Autumn 1, Winter 1), and in the second (Spring 2) wind direction. V79 showed cytotoxicity in all samples. The three biomarkers were concordant in characterization Site NO with worse quality, compatible with the greater pollutants dispersion in the first wind direction. All PM2.5 concentrations were lower than those recommended by air quality standards but genotoxic effects were detected in all samples, corroborating that these standards are inadequate as quality indicators. The Salmonella/microsome assay proved sensitive to PM2.5 mutagenicity, with an outstanding influence of nitroarenes and aromatic amines. Analyses using CA and the micronucleus test broadened the levels of response that involve different damage induction mechanisms. Results show that the complex PM2.5 composition can provoke various genotoxic effects and the use of different bioassays is essential to understand its effects.

Mutagenicity of particulate matter fractions in areas under the impact of urban and industrial activities.

Organisms in the environment are exposed to a mixture of pollutants. Therefore the purpose of this study was to analyze the mutagenicity of organic and inorganic responses in two fractions of particulates (TSP and PM2.5) and extracts (organic and aqueous). The mutagenicity of organic and aqueous particulate matter extracts from urban-industrial and urban-residential areas was evaluated by Salmonella/microsome assay, through the microsuspension method, using strain TA98 with and without liver metabolization. Additionally, strains YG1021 and YG1024 (nitro-sensitive) were used for organic extracts. Aqueous extracts presented negative responses for mutagenesis and cytotoxicity was detected in 50% of the samples. In these extracts the presence of potential bioavailable metals was identified. All organic extracts presented mutagens with a higher potential associated with PM2.5. This study presents a first characterization of PM2.5 in Brazil, through the Salmonella/microsome assay. The evaluation strategy detected the anthropic influence of groups of compounds characteristically found in urban and industrial areas, even in samples with PM values in accordance with quality standards. Thus, the use of a genotoxic approach in areas under different anthropic influences will favor the adoption of preventive measures in the health/environment relation.

Mutagenicity assessment in a river basin influenced by agricultural, urban and industrial sources.

The genotoxic potential of samples from a river basin under impact of agricultural, urban and industrial activities was studied, to investigate the influence of climatic variations on the mutagenicity. Three sites were analyzed, a reference-SI121-and two with strong anthropic influence-SI028 and SI008. The Salmonella/microsome assay was performed in the presence/absence of hepatic metabolic system in samples of water and organic extracts. Different strains were used to identify frameshift mutagens, base-pair substitutions and oxidative damage. Indicative mutagens were detected especially with metabolization. The toxic response, which was quite frequent, may have interfered in the mutagenicity detection. The adverse impact of anthropic activities was detected through recurring cytotoxic and mutagenic responses at the site of greater urban and industrial concentration. The data suggest the influence of climatic conditions on mutagenic response, reinforcing the need to investigate mutagenicity for a prolonged period to a better risk assessment of exposure.