Jocelita Aparecida Vaz Rocha

Genetic biomonitoring of an urban population exposed to mutagenic airborne pollutants.

Biomonitoring studies have increased as a consequence of risks and effects to human health on exposure to environmental contaminants, mainly air pollutants. Genetic biomarkers are useful tools for the early assessment of exposure to occupational and environmental pollution. The objective of the present study was to investigate genotoxic effects on people residing and/or working downwind from an oil refinery in southern Brazil and the mutagenic activity of airborne particulate matter (PM10). Samples of peripheral blood and buccal mucosa cells were evaluated using the single-cell gel electrophoresis assay (comet assay) and the micronucleus (MN) assay, respectively. PM10 samples were collected in the target site and the organic matter extraced with dichloromethane was assessed for mutagenic activity in the Salmonella/microsome assay. The exposed group (n=37) was compared to a reference group (n=37) of subjects living in an urban area with limited traffic and industrial influence, located far from the main industrial areas. All PM10 organic extracts showed mutagenic positive responses and the effect decreased in the presence of S9 mix indicating that the predominant compounds present were direct-acting mutagens. The responses of YGs strains are consistent with aromatic amines and nitroarenes being present in the PM10 extracts. The group in the area under the influence of the oil refinery (exposed group) showed significantly higher DNA damage in lymphocytes than the reference group. The MN frequencies in buccal mucosa were very low for both groups and no difference between groups was observed. No association was found between age and tobacco smoking habit and level of DNA damages measured by the comet assay. The results indicate that the comet assay was a sensitive tool to detect DNA damage in subjects under the influence of an oil refinery, with marked genotoxic activity in the atmospheric environment.

Mutagenic activity of airborne particulate matter in a petrochemical industrial area

Exposure to airborne particulate matter has adverse effects on human health and ecosystem. Mutagenic activity of airborne particulate organic matter extracts in three time periods from total suspended particles (TSP) and particles less than 10 microm (PM10) was evaluated in an area under the influence of a petrochemical industry located in the town of Triunfo, Brazil. The extracts were investigated using the Salmonella/microsome assay, with the microsuspension method. The extracts were obtained by sonication extracted using dichloromethane (DCM) solvent. The fractions were tested for mutagenicity with the Salmonella typhimurium strains TA98 (with and without metabolic activation), TA98NR and TA98/1,8DNP(6); or YG1021 and YG1024. A positive frameshift mutagenic response was observed for the environmental samples during the different periods. The responses according to percentage of extractable organic matter (EOM%), EOM/m(3), revertants/microg (rev/microg) and revertants/m(3) (rev/m(3)) were lower for TSP than for PM10 extracts. The highest rev/m(3) values were observed in PM10 extract samples collected in winter, July 2005, in the presence (13.79 rev/m(3)) or absence (6.87 rev/m(3)) of S9 fraction. Similarly in the first (1995) or second period (2000) the highest values for TSP were observed in winter, but with lower activity (3.00 and 0.89 rev/m(3) respectively). The responses observed for the nitrosensitive strains suggest the contribution of nitro, amino and/or hydroxylamino derivatives of PAHs to the total mutagenicity of matter extracted from airborne particles. The Salmonella/microsome assay was a sensitive method to define areas contaminated by genotoxic compounds, even in samples with TSP or PM10 values that are acceptable according to legal environmental quality standards, favoring environmental control measures with an effective response seen in the populations improved quality of life.

Soil mutagenicity as a strategy to evaluate environmental and health risks in a contaminated area.

Soil can be a storage place and source of pollutants for interfacial environments. This study looked at a site contaminated with wood preservatives as a source of mutagens, defined routes and extent of the dispersion of these contaminants by particle remobilization and atmospheric deposition, considering an evaluation of risk to human health by quantifying mutagenic risk. Soil sampling sites were chosen at gradually increasing distances (150, 500 and 1700m) from SI (industrial area pool) and indoor dust (pool in an area at risk at 385m and at 1700m). Mutagenesis was evaluated in the Salmonella/microsome assay, TA98, TA97a and TA100 strains with and without S9 mix, YGs strains 1041, 1042 and 1024 for nitrocompounds. Acid extracts were analyzed to define the effects of metals and organics for polycyclic aromatic hydrocarbons (PAHs) and nitroderivates, besides concentrations of these compounds and pentachlorophenol (PCP). Risk to human health was obtained from the relation between the quantified potential of mutagenic risk and estimated soil ingestion for children according to USEPA. Metal concentrations showed a gradient of responses with As, Cr and Cu (total metal) or Cr and Cu (fraction available) higher for SI. However, mutagenic effects of the mixtures did not show this grading. Site SR1700, without a response, was characterized as a reference. In organic extracts, the mutagenesis responses showed the mobility of these compounds from the source. In the surrounding area, a smaller pattern similar to SI was observed at SR150, and at the other sites elevated values of direct mutagenesis at SR500 and diminished effects at SR1700. Tests with YG strains indicated that nitrated compounds have a significant effect on the direct mutagenesis found, except SR500. The investigation of indoor dust in the surrounding area enabled confirmation of the particle resuspension route and atmospheric deposition, showing responses in mutagenicity biomarkers, PAH concentrations and PCP dosage similar to SI. The range of values obtained, considering the soil masses needed to induce mutagenicity was 0.02 to 0.33g, indicating a high risk associated with human populations exposed, since these values found surpass the standard estimate of 200mg/day of rate of soil ingestion for children according to USEPA. The study showed that it is essential to evaluate the extent of contamination from the soil to delimit remedial measures and avoid damage to the ecological balance and to human health.

Comparative genotoxicity of airborne particulate matter (PM2.5) using Salmonella, plants and mammalian cells.

This study compared genotoxicity in bacteria, plants and cell cultures in areas at risk of exposure to airborne pollution. Genotoxicity of moderately polar organic extracts of PM2.5 from areas with urban airborne pollution (Site 1) and urban-industrial pollution (Site 2) was evaluated using microsuspension assays in Salmonella/microsome, micronucleus test with Tradescantia pallida (Trad-MN) with acute exposure, and in V79 (V79-MN) cells, Comet assay in V79 and human lymphocyte, besides Trad-MN in situ at Site 1. In the Salmonella/microsome assay all samples presented frameshift mutagenic activity (-/+S9), most intense at Site 2 (rev/m(3)). The presence of nitro-PAHs and hydroxylamines in PM2.5 was shown by positive mutagenic responses with YG1021 and YG1024. In tests with Trad-MN, no significant genotoxic responses were found (MN %). In V79-MN a genotoxic response was not found. The Comet assay damages were found in the DNA at Site 1 in both cell systems. Non-detection of genotoxicity with Trad-MN at sites or in environmental samples from polluted areas detected using other biomarkers suggests the need for careful evaluation when biomonitoring genotoxic compounds using plants. The microsuspension assay in Salmonella/microsome was sensitive to detect and identify different classes of airborne mutagenic compounds present in fine particulate matter in Porto Alegre city, showing that monitoring air quality with PM2.5 using this methodology is relevant.

Toxicogenetic monitoring in urban cities exposed to different airborne contaminants

Microparticles found in the air may be associated with organic matter that contains several compounds, such as Polycyclic Aromatic Hydrocarbons (PAHs) and nitro-PAHs, and may pose a significant risk to human health, possibly leading to DNA mutations and cancers. This study associated genotoxicity assays for evaluating human exposure with the atmospheric air of two urban areas in southern Brazil, that received different atmospheric contributions. Site 1 was under urban-industrial influence and the other was a non-industrial reference, Site 2. Organic extracts from the airborne particulate matter were tested for mutagenicity via the Salmonella/microsome assay and analyzed for PAH composition. Cells samples of people residing in these two cities were evaluated using the comet and micronucleus assay (MN).Concentrations of the individual PAHs ranged from 0.01 ng/m(3) (benzo[a]anthracene) to 5.08 ng/m(3) (benzo[ghi]perylene). As to mutagenicity analysis of airborne, Site 1 presented all the mutagenic responses, which varied from 3.2±1.22 rev/m(3) (TA98 no S9) to 32.6±2.05 rev/m(3) (TA98, S9), while Site 2 ranged from negative to minimal responses. Site 1 presented a high quantity of nitro and amino derivatives of PAHs, and peaked at 56.0±3.68 rev/μg (YG1024 strain). The two groups presented very low DNA damage levels without intergroup difference. Although Site 1 presented high mutagenic responses in the air samples, high PAH levels, healthy people exposed to this environment did not show significative damage in their genetic material. However, the evaluation of different environmental and genetic damage in such population is necessary to monitor possible damages.

Extraction parameters in the mutagenicity assay of soil samples.

This study aimed at investigating parameters of chemical extraction associated with the detection of mutagenicity in soil samples extracts. In order to evaluate the extraction efficiency of inorganic mutagens, besides the chemical analysis of metals, the Salmonella/microsome assay was performed in the preincubation and microsuspension procedures, using two solvents, and using two extraction methodologies. The efficiency of two organic compound extraction methods was compared by qualitative analysis using CG/MS in Scan mode. The results of the analysis of inorganic extracts correlated with the mutagenicity results. Mutagenic effects were detected only in the acidic extracts of soil that were shaken, in the microsuspension assay, both in the presence and absence of metabolic activation. The other conditions tested demonstrated higher cytotoxicity and negative mutagenic effects. As to the organic compounds, Accelerated Solvent Extraction (ASE) proved more effective than extraction using ultrasound (sonication). This study will help the implementation of extraction parameters to evaluate the presence of mutagenic substances in soil samples, both of inorganic and organic origins, suggesting the implementation of acidic extraction for the assessment of inorganic mutagenicity from soil samples and confirming the efficiency of ASE extraction for the assessment of organic compounds.

Use of bioindicators to evaluate air quality and genotoxic compounds in an urban environment in Southern Brazil

Biological indicators are widely used to monitor genotic compounds and air quality in urban environments. Parmotrema tinctorum and Teloschistes exilis have been used to verify the presence of pollutants and analyze morphophysiological alterations in the thallus of species caused by their action. Species were exposed for seven months, in an urban area, in southern Brazil. Mutagenicity and cytotoxicity of PM10 organic extracts were assessed in the Salmonella/microsome assay at two stations. High concentrations of S, Pb, Cr, Zn and Hg were registered in the last period of exposure and more significant morphophysiological damages were verified in the lichens. Generally a higher mutagenic activity is observed in organic extracts of airborne particulate matter during the first months and in the third period of exposure of lichens. In addition, nitro compounds was detected through nitro-sensitive strains. Lichens and mutagenic biomarkers enabled the evaluation of air quality and the presence of environmentally-aggressive compounds.

Salmonella mutagenicity assessment of airborne particulate matter collected from urban areas of Rio Grande do Sul State, Brazil, differing in anthropogenic influences and polycyclic aromatic hydrocarbon levels.

Urban areas are both major sources and major targets of air pollution. The atmospheric environment receives diverse chemical substances, including genotoxic agents that may affect human health. The purpose of this study was to evaluate and compare the atmospheric quality in two urban areas in Rio Grande do Sul State (Brazil), under the influence of greater (Site 1) or lesser (Site 2) anthropogenic sources. Polycyclic aromatic hydrocarbons (PAHs) of environmental interest were quantified and the Salmonella/microsome assay was used for the measurement of mutagenicity. Organic compounds extracted from the airborne particulate matter were analyzed by high-performance liquid chromatography (HPLC) to detect PAHs of interest (known or possible carcinogens). The organic extracts were also tested for mutagenic and cytotoxic activity in the Salmonella/microsome assay with strains TA98, TA100, YG1021 and YG1024, with or without S9 activation. At Site 1, benzo[ghi]perylene (BghiP) and indeno[1,2,3-cd]pyrene (IP) were found at higher concentrations and mutagenicity (revertants per μg extract) varied from 1.0±0.25 (TA98, no S9) to 5.2±0.45 (TA98, S9). At Site 2, BghiP and IP were present in larger amounts and the mutagenic responses ranged from 0.6 to 3.7 revertants per μg (both in TA98, S9). The occurrence of BghiP and IP may be related to vehicular emissions. These and the other PAHs studied, as well as the nitro compounds, may contribute to the mutagenicity found in these airborne particles.

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.