Organisms in polluted environments are typically exposed to a complex mixture of chemical contaminants. The great concern about the health of aquatic ecosystems has led to the increased use of biomarkers over the past years. The aim of this work was to review the papers published from 2000 to 2015, which used biomarkers to assess the health of aquatic ecosystems in Brazil. A research resulted in 99 eligible papers. More than 80% of studies were conducted in the states of São Paulo and Rio Grande do Sul. Approximately 63% of studies used fish as bioindicator, whereas the micronucleus test and biochemical analyses were the most used biomarkers. A multibiomarker approach was used by 60.6% of studies, while 39.4% used one single biomarker. Furthermore, 68% were field studies and more than 75% of these used control animals sampled at reference sites. A relationship between the biomarker responses and pollution was reported by 87% of studies; however, 43.4% of studies analyzed only one sampling period, limiting comparisons and comprehension about possible seasonal variations. This review evidenced some weak points in studies using biomarkers in Brazil, especially related to the lack of studies in two important biomes (the Pantanal and the Amazon Rainforest) and experimental designs (small sample size, sampling in one single period, use of one single biomarker). Thus, future studies should consider mainly the use of multiple biomarkers, greater sample size, seasonal sampling and water physicochemical parameters to better diagnose the health of aquatic ecosystems.

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The Sinos River is an important water supply in Southern Brazil and receives industrial, agricultural, and domestic effluents which may affect aquatic biota. Water physicochemical and microbiological analyses, biomarker responses (scaled mass index (SMI), gill histopathology, and micronucleus and nuclear abnormality (MN and NA) frequencies), and metal bioaccumulation in muscle were assessed in the fish species Bryconamericus iheringii (Characidae) captured at three sampling sites (S1, S2, and S3) in four sampling periods. The mean values of five parameters (total phosphorus, thermotolerant coliforms, aluminum, iron, and lead) exceeded the limits established by the Brazilian legislation at the three sampling sites. Although physicochemical analysis indicated higher impacts at S3, in some samples, significantly higher MN frequencies and bioaccumulation of manganese in fish muscle were observed at S1, whereas low SMI and higher concentrations of aluminum and zinc in fish muscle were found at S2. Histopathological alterations in gills were observed in fish collected at the three sampling sites; however, no spatial differences were observed, indicating similar environmental conditions with respect to this biomarker. Moreover, temporal variation of biomarker responses and metal bioaccumulation were found at all sampling sites. Furthermore, the consumption of fish from the Sinos River should be avoided given the concentrations of chromium (all samples), cadmium, and lead in fish muscle above the threshold for safe human consumption.

http://dx.doi.org/10.5007/2175-7925.2016v29n1p75A contaminação de ecossistemas aquáticos por alumínio (Al) é geralmente ocasionada por várias atividades antropogênicas. Diversas alterações morfológicas, fisiológicas e bioquímicas observadas em organismos aquáticos podem ser atribuídas à exposição ao Al. Neste contexto, o objetivo desse estudo foi investigar os efeitos da exposição aguda de peixes da espécie Astyanax jacuhiensis a diferentes concentrações de Al através da histologia de brânquias e frequência de micronúcleos (MN) e anormalidades nucleares (AN) em eritrócitos. Os animais foram expostos às concentrações subletais de 0.3 mg/L e 30 mg/L de alumínio em pH neutro por 72 h. Um grupo controle foi mantido em água filtrada. As alterações branquiais foram caracterizadas por hiperplasia e hipertrofia de células epiteliais, fusão lamelar, edema, descolamento epitelial, aneurisma e necrose. Um aumento significativo (p<0.05) foi observado na frequência de lamelas alteradas nos grupos expostos às duas concentrações de Al em comparação aos animais controle. No entanto, não foram observadas diferenças significativas nas frequências de MN e AN. Embora não tenham sido encontradas evidências de genotoxicidade, os resultados encontrados na análise morfológica sugerem que o Al foi tóxico para os peixes nas duas concentrações testadas em pH neutro.

The Sinos River basin is impacted by industrial and agricultural activities, as well as by low rates of urban wastewater treatment. The purpose of this study was to monitor de Sinos River water quality using the micronucleus test in fish and the analysis of water physicochemical parameters. Bryconamericus iheringii specimens were captured in December 2013 (summer) and July 2014 (winter) at two sites located in the Sinos River: Caraá, in the upper section of the basin, and Parobé, in the middle section. After capture, animals were immediately killed and blood samples were collected for the micronucleus test. No significant differences were observed in micronucleus frequencies between sites and sampling periods. However, in the summer, nuclear abnormalities frequencies observed in Parobé were significantly higher than in Caraá. A higher frequency of nuclear abnormalities was also found in fish captured in Caraá during winter, in comparison with frequencies found in the summer. The results for the water physicochemical analysis showed values of total phosphorous, aluminum, lead, copper and iron above the allowed limits established by the Brazilian legislation. The nuclear abnormalities induction found in the present study may be associated to the presence of cytogenotoxic substances in the water.