Luciano Basso da Silva

Cytogenetic biomonitoring of Brazilian workers exposed to pesticides: micronucleus analysis in buccal epithelial cells of soybean growers.

Pesticides have been considered potential chemical mutagens and various agrochemical ingredients possess mutagenic properties. Biomonitoring provides a useful tool to estimate the genetic risk from exposure to a complex mixture of chemicals. In general genetic damage associated with pesticides occurs in human populations subject to high exposure levels due to intensive use, misuse or failure of control measures. Few studies have been carried out using the micronucleus (MN) analysis in buccal cells of farm workers and, from the available data, only one has found a positive relationship. Micronuclei were analyzed in 29 Brazilian workers exposed to pesticides in soybean fields and in 37 non-exposed individuals. The results obtained indicate that the mean number of cells with MN in the exposed group (3.55+/-2.13) was significantly higher than in the control group (1.78+/-1.23). The number of cells with MN was not influenced by age, smoking habit, smoking time, number of cigarettes/day, alcohol consumption and years of exposure to pesticides. The genotoxic potential of the pesticides used in soybean fields may explain the detectable increase of cells with MN in exposed workers.

Evaluation of Sinos River water genotoxicity using the comet assay in fish

The Sinos River, in southern Brazil, is polluted by industrial discharges and untreated urban wastes. Fish genotoxicity biomarkers are valuable parameters for environmental risk assessment. In this study, we used the comet assay to detect genotoxicity due to multiple sources of pollution in the peripheral blood of a native fish species (Hyphessobrycon luetkenii). In addition, we analysed possible DNA damage from aluminum, lead, chromium, copper, nickel, iron and zinc contamination. Water samples were collected seasonally from three sampling sites and the fish were assessed under laboratory conditions. Water chemical analysis showed an increased level of aluminum and iron in most of the samples at sites 2 and 3, located in the middle and lower river course, respectively. The index of DNA damage assessed by the comet assay demonstrated no significant differences in different seasons or at the different sampling sites, while the frequency of cells with DNA damage was higher in water samples collected at sites 1 and 2 during the spring season. None of the metals studied seems to be associated with the increase in the frequency of cells with DNA damage observed during the spring season. The results of this study indicate that the Sinos River is contaminated with substances that are genotoxic to fish, including the waters near the river spring.

Composição e distribuição vertical de pteridófitas epifíticas sobre Dicksonia sellowiana Hook. (Dicksoniaceae), em floresta ombrófila mista no sul do Brasil

Dicksonia sellowiana Hook., a tree fern species, is illegally extracted from the Mixed Ombrophylous Forest of southern Brazil, what changes the vegetation structure and reduces the availability of micro-habitats for epiphytic species. The composition and the vertical distribution of epiphytic pteridophytes were studied on D. sellowiana. The study was carried out in a Mixed Ombrophylous Forest area, at the Parque Municipal da Ronda in the State of Rio Grande do Sul, Brazil. One hundred and sixty four phorophytes were selected and their caudices were divided at intervals of 1 m, from the ground. At each interval the occurrence of pteridophyte species was recorded, and the frequency by phorophyte and by interval was calculated. Twenty species were recorded, from 13 genera and seven families, and habitual holoephiphytes predominated. The largest specific richness was found in Aspleniaceae (6) and in the Asplenium L. genus (6). The species with the highest relative frequency on the phorophytes were Trichomanes angustatum Carmich., Blechnum binervatum (Poir.) C.V. Morton & Lellinger and Vittaria lineata (L.) Sm.. Considering a sub-sample of 60 phorophytes, T. angustatum and B. binervatum had decreasing frequency of occurrence from the ground up to 4 m. The average richness was higher in the first three intervals. The richness found over the caudices of D. sellowiana represented 67% of the total epiphytic pteridophytes found in Mixed Ombrophylous Forest area, at the Parque Municipal da Ronda and this shows the importance of this host plant for the maintenance of epiphytic species in the forest environment.

Chromosomal inversion polymorphism in Drosophila mediopunctata: seasonal, altitudinal, and latitudinal variation

The most polymorphic chromosome for inversions in Drosophila mediopunctata is the chromosome II, where 17 inversions have been found, eight of which occurring in the distal region and nine in the proximal region. We present an analysis of the chromosome II inversion polymorphism with respect to seasonal, altitudinal and latitudinal variation. In D. mediopunctata from the Parque Nacional do Itatiaia (southeastern Brazil), the frequencies of three of the distal inversions (namely DA, DS, and DP) vary seasonally. These inversions also show altitudinal clines in their frequencies. This microgeographic pattern was not observed on a macrogeographic scale. D. mediopunctata from Porto Alegre are less polymorphic for inversions than other populations, the most remarkable reduction occurring in the proximal region of chromosome II. There is a considerable difference between D. mediopunctata from Campinas and specimens from Serra do Japi, which are separated by only 50 km. In contrast, D. mediopunctata from Serra do Japi are much more similar to specimens from the Parque Nacional do Itatiaia, which is 200 km far.

Toxicological evaluation of landfill leachate using plant (Allium cepa) and fish (Leporinus obtusidens) bioassays.

The disposal of municipal waste in landfills may pose an environmental problem because the product of the decomposition of these residues generates large volumes of leachate, which may present high toxicity. The aim of this study was to assess the toxic and genotoxic effects of a sample of untreated leachate in fish (Leporinus obtusidens) and onions (Allium cepa). The leachate was collected in a landfill located in the region of Vale do Rio dos Sinos, southern Brazil. The fish were exposed to raw leachate, at concentrations of 0.5%, 1.0%, 5%, 10% and 20% for 6 days, while the bulbs of A. cepa were exposed to concentrations of 5%, 10%, 25%, 50% and 100% for 48 h. For fish, the concentrations of 5%, 10% and 20% were lethal, thus indicating high toxicity; however, sublethal concentrations (0.5% and 1.0%) showed no genotoxicity by micronucleus test when compared with the control group. In the bioassays involving onions, high toxicity was observed, with significant reduction of root growth and mitotic index in bulbs exposed to the 100% concentration of the leachate. An increase in the frequency of chromosome abnormalities in the A. cepa root cells in anaphase–telophase was observed in accordance with the increase in the concentration of leachate (5%, 10%, 25% and 50%), with values   significantly greater than the control, at the highest concentration. The results showed that the leachate contains toxic and genotoxic substances, thus representing a major source of environmental pollution if not handled properly.

A multibiomarker approach in rats to assess the impact of pollution on Sinos River, Southern Brazil

The aim of this study was to determine the feasibility of combining water quality analysis with different biomarkers to characterise the relationship between anthropogenic contamination and biotic response in the Sinos River, southern Brazil. Wistar rats were studied using three biomarkers combined with physical, chemical and microbiological analysis to assess the effects of pollution at four sampling sites. The induction of oxidative stress was quantified by MDA levels in peripheral blood, lymphocyte DNA damage was determined using the comet assay, and histopathological changes were analysed in the liver. After sampling, animals were allowed to drink the river water during a 48 hours period. No increase in oxidative stress and DNA damage was observed. However, liver damage was observed in the animals exposed to water samples, indicating that the Sinos River is contaminated with hepatotoxic substances. Water analyses confirmed that water quality decreased downriver.

Assessment of DNA damage in floriculturists in southern Brazil.

The aim of this study was to assess possible genotoxic effects on floriculturists in a region of the state of Rio Grande do Sul, in the south of Brazil, using the micronucleus test (MN) and comet assay. Thirty-seven floriculturists and 37 individuals not exposed to pesticides participated in the study. The micronucleus test was performed with epithelial cells of the oral mucosa. In the microscopic analysis, 2000 cells were evaluated per subject, verifying the frequency of MN and the frequency of other nuclear abnormalities (nuclear buds, binucleated cells, and karyorrhexis). For the comet assay in the peripheral blood lymphocytes, 100 cells were classified in five classes, according to the migration of DNA fragments, thereby generating the frequency of damaged cells and the damage index. There was no difference between the exposed and control groups in the frequencies of MN and other nuclear abnormalities in the epithelial cells of the oral mucosa. However, the comet assay showed that both the frequency of DNA damaged cells and the damage index were significantly greater in the exposed group. The results therefore indicate that floriculturists are exposed to mixtures of pesticides with genotoxic potential.

Water quality assessment of the Sinos River – RS, Brazil

Worldwide environmental pollution is increasing at the same rate as social and economic development. This growth, however, is disorganized and leads to increased degradation of water resources. Water, which was once considered inexhaustible, has become the focus of environmental concerns because it is essential for life and for many production processes. This article describes monitoring of the water quality at three points along the Sinos River (RS, Brazil), one in each of the upper, middle and lower stretches. The points were sampled in 2013 and again in 2014. The water samples were analyzed to determine the following physical and chemical parameters plus genotoxicity to fish: metals (Cr, Fe, Al), chemical oxygen demand, biochemical oxygen demand, chlorides, conductivity, total suspended solids, total phosphorous, total and fecal coliforms, pH, dissolved oxygen, turbidity, total Kjeldahl nitrogen nitrate and ammoniacal nitrogen. Genotoxicity was tested by exposing individuals of the species Astyanax jacuhiensis to water samples and then comparing them with a control group exposed to water from the public water supply. The results confirmed the presence of substances with genotoxic potential at the sample points located in the middle and lower stretches of the river. The results for samples from the upper stretch, at P1, did not exhibit differences in relation to the control group. The physical and chemical analyses did not detect reductions in water quality in the lower stretch, as had been expected in view of the large volumes of domestic and industrial effluents discharged into this part of the river.

Evaluation of genotoxicity and cytotoxicity of water samples from the Sinos River Basin, southern Brazil.

Some water bodies in the Sinos River Basin (SRB) have been suffering the effects of pollution by residential, industrial and agroindustrial wastewater. The presence of cytotoxic and genotoxic compounds could compromise the water quality and the balance of these ecosystems. In this context, the research aimed to evaluate the genotoxicity and cytotoxicity of the water at four sites along the SRB (in the cities of Santo Antônio da Patrulha, Parobé, Campo Bom and Esteio), using bioassays in fish and cell culture. Samples of surface water were collected and evaluated in vitro using the Astyanax jacuhiensis fish species (micronucleus test and comet assay) and the Vero lineage of cells (comet assay and cytotoxicity tests, neutral red - NR and tetrazolium MTT). The micronucleus test in fish showed no significant differences between the sampling sites, and neither did the comet assay and the MTT and NR tests in Vero cells. The comet assay showed an increase in genetic damage in the fish exposed to water samples collected in the middle and lower sections of the basin (Parobé, Campo Bom and Esteio) when compared to the upper section of the basin (Santo Antônio da Patrulha). The results indicate contamination by genotoxic substances starting in the middle section of the SRB.

Genotoxic Potential and Physicochemical Parameters of Sinos River, Southern Brazil

The present study aimed to evaluate the physicochemical parameters and the genotoxic potential of water samples collected in the upper, middle, and lower courses of the Sinos River, southern Brazil. The comet assay was performed in the peripheral blood of fish Hyphessobrycon luetkenii exposed under laboratory conditions to water samples collected in summer and winter in three sampling sites of Sinos River. Water quality analysis demonstrated values above those described in Brazilian legislation in Parobé and Sapucaia do Sul sites, located in the middle and in the lower courses of the Sinos River, respectively. The Caraá site, located in the upper river reach, presented all the physicochemical parameters in accordance with the allowed limits in both sampling periods. Comet assay in fish revealed genotoxicity in water samples collected in the middle course site in summer and in the three sites in winter when compared to control group. Thus, the physicochemical parameters indicated that the water quality of the upper course complies with the limits set by the national guidelines, and the ecotoxicological assessment, however, indicated the presence of genotoxic agents. The present study highlights the importance of combining water physicochemical analysis and bioassays to river monitoring.