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.Keywords: genotoxicity, river pollution, biomarkers, metals. Avaliação da genotoxicidade da água do rio dosSinos utilizando o ensaio cometa em peixes ResumoO rio dos Sinos, no sul do Brasil, é poluído tanto por descargas industriais como por resíduos urbanos não tratados. Os biomarcadores de genotoxicidade em peixes são parâmetros valiosos para a determinação de risco ambiental. Neste estudo, utilizamos o ensaio cometa em sangue periférico de um peixe nativo (Hyphessobrycon luetkenii) para detectar a genotoxicidade devido a múltiplas fontes de poluição. Além disso, analisamos a possível influência da contaminação por alumínio, chumbo, cromo, cobre, níquel, ferro e zinco sobre o dano de DNA. Amostras de água foram coletadas sazonalmente em três pontos de coleta e os peixes foram expostos sob condições de laboratório. A análise química da água mostrou níveis elevados de alumínio e ferro na maioria das amostras dos pontos 2 e 3, localizados nos cursos médio e inferior do rio, respectivamente. O índice de dano de DNA estimado pelo ensaio cometa não demonstrou diferenças significativas tanto entre estações como entre pontos de coleta, enquanto que a frequência de células com dano de DNA apresentou valores superiores nas amostras de água coletadas durante a primavera nos pontos 1 e 2. Nenhum dos metais estudados parece estar associado com o aumento na frequência de células com dano de DNA observado durante a primavera. Os resultados deste estudo indicam que o rio dos Sinos está contaminado com substâncias genotóxicas para os peixes, incluindo as águas próximas à nascente do rio. results. Moreover, genotoxicity assays in fish erythrocytes has not been used to evaluate the genot...
Viral gastroenteritis and other waterborne diseases are a major concern for health in Brazil. A number of studies were conducted about the presence of viruses on water samples from Brazilian areas. However, the knowledge about the occurrence of viral contamination of drinking water sources in rural settings of the country is insufficient. On the present work, 15 samples from 5 dairy farms located at the municipality of Tenente Portela were collected and analysed for the presence of human adenoviruses (HAdV), as well as human enteroviruses (EV) and rotaviruses (RV). HAdV was present on 66.66% of the water samples, and have been found in all samples from artesian wells and springs, which are used as sources of drinking water for the individuals inhabiting those farms. EV and RV found only in one sample each. The detection rates of HAdV on the water from these dairy farms are alarming and point towards a situation of elevated environmental contamination by fecal microorganisms of human origin and poor basic sanitation conditions.
Torque teno virus (TTV) was surveyed in tap water collected in schools from three municipalities located in the south of Brazil. TTV genomes were found in 11.7 % (4/34) of the samples. TTV DNA was detected in 10.5 % (2/19) of the samples collected at the city of Caxias do Sul and in 25 % (2/8) of the samples from Pelotas. Those cities have a low rate of sewage treatment. All samples from Santa Cruz do Sul, which has nearly 92 % of its sewage treated, were negative. These results suggest that the amount of sewage treated may have an effect on the detection rates of TTV DNA in drinking water in a given urban area, showing a mild negative correlation (r = -0.76), when comparing the percentage of sewage treatment to the detection of TTV genomes. The detection rate of TTV was also compared with Escherichia coli, showing a strong correlation (r = 0.97), indicating that TTV may be a suitable marker of fecal contamination.
Climate variables may interfere with the environmental persistence and spread of pathogenic microorganisms. This study aimed to investigate the occurrence of human adenovirus (HAdV) and total and thermotolerant coliforms in treated and untreated water and report gastroenteritis cases in seven cities located in the hydrographic basin of the Sinos River (HBSR), Southern Brazil. The data on water quality from samples collected at catchment areas of HBSR from March to December 2011 were compared with precipitation records, virus detection rates and viral loads, and information on enteric diseases among residents of the region. There was a marked increase in precipitation intensity in April, July, and August and a decrease in May and November. The number of HAdV genome copies (gc) in untreated water ranged from 2.1×10(8) gc/L in June to 7.8×10(1) gc/L in December, and in treated water, from 6.3×10(4) gc/L in September to 4.1×10(1) gc/L in November. The most probable number (MPN) of total coliforms ranged from 5×10(1) MPN/100 mL in December to 2.4×10(5) MPN/100 mL in July, and thermotolerant coliforms ranged from 1×10(1) MPN/100 mL in August to 6.9×10(4) MPN/100 mL in July. A total of 79 hospital admissions due to gastroenteritis were registered in the cities studied. The results for coliforms in untreated water demonstrate deficits in sanitation and wastewater treatment. These findings also indicate a possible relationship between the occurrence of rainfalls after dry periods and an increase in the number of gastroenteritis cases and in HAdV load quantified in surface water collected for conventional potabilization.
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.
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