Assessing the spatial pattern of a river water quality in southern Brazil by multivariate analysis of biological and chemical indicators / Avaliação do padrão espacial da qualidade da água de um rio no Sul do Brasil por meio da análise multivariada de indicadores biológico e químicos

Abstract This study assessed the genotoxicity and chemical quality of the Rio dos Sinos, southern Brazil. During two years, bimonthly, cuttings of Tradescantia pallida var. purpurea with flower buds were exposed to river water samples from Caraá, Santo Antônio da Patrulha, Taquara and Campo Bom, which are municipalities located in the upper, middle and lower stretches of the Rio dos Sinos basin. Simultaneously, chemical parameters were analyzed, rainfall data were surveyed and negative (distilled water) and positive (0.1% formaldehyde) controls were made. Micronuclei (MCN) frequencies were determined in tetrads of pollen grain mother cells. From the upper stretch toward the lower, there was an increase in the frequency of MCN and in concentrations of chemical parameters. Cadmium, lead, copper, total chromium and zinc were present at the four sites and a concentration gradient was not demonstrated along the river. The multivariate analysis revealed that two principal components exist, which accounted for 62.3% of the observed variances. Although genotoxicity was observed in Santo Antônio da Patrulha, the water presented higher mean values for most of the assessed parameters, in the lower stretch, where urbanization and industrialization are greater. The spatial and temporal pattern of water quality observed reinforces the importance of considering the environmental factors and their effects on organisms in an integrated way in watercourse monitoring programs.

Resumo Este estudo avaliou a genotoxicidade e a qualidade química do Rio dos Sinos, Sul do Brasil. Durante dois anos, com periodicidade bimensal, ramos de Tradescantia pallida var. purpurea com botões florais foram expostos a amostras de água do rio de Caraá, Santo Antônio da Patrulha, Taquara e Campo Bom, municípios localizados nos trechos superior, médio e inferior da Bacia do Rio dos Sinos. Simultaneamente, foram analisados parâmetros químicos, levantados dados de precipitação e realizados controles negativos (água destilada) e positivos (0,1% formaldeído). Frequências de micronúcleos (MCN) foram determinadas em tétrades de células-mãe de grão de pólen. Do trecho superior em direção ao inferior, foi observado aumento da frequência de MCN e na concentração de parâmetros químicos. Cádmio, chumbo, cobre, cromo total e zinco estiveram presentes nos quatro pontos amostrais, sem apresentar um gradiente de concentração ao longo do rio. A análise multivariada demonstrou a existência de dois componentes principais que explicaram 62,3% das variâncias observadas. Embora em Santo Antônio da Patrulha tenha sido observada genotoxicidade, a água do Rio dos Sinos apresentou valores médios superiores para a maioria dos parâmetros avaliados no trecho inferior, onde a urbanização e a industrialização são maiores. O padrão espacial e temporal de qualidade da água observado reforça a importância de considerar os fatores ambientais e seus efeitos nos organismos de forma integrada em programas de monitoramento de cursos hídricos.

Assessing the spatial pattern of a river water quality in southern Brazil by multivariate analysis of biological and chemical indicators.

This study assessed the genotoxicity and chemical quality of the Rio dos Sinos, southern Brazil. During two years, bimonthly, cuttings of Tradescantia pallida var. purpurea with flower buds were exposed to river water samples from Caraá, Santo Antônio da Patrulha, Taquara and Campo Bom, which are municipalities located in the upper, middle and lower stretches of the Rio dos Sinos basin. Simultaneously, chemical parameters were analyzed, rainfall data were surveyed and negative (distilled water) and positive (0.1% formaldehyde) controls were made. Micronuclei (MCN) frequencies were determined in tetrads of pollen grain mother cells. From the upper stretch toward the lower, there was an increase in the frequency of MCN and in concentrations of chemical parameters. Cadmium, lead, copper, total chromium and zinc were present at the four sites and a concentration gradient was not demonstrated along the river. The multivariate analysis revealed that two principal components exist, which accounted for 62.3% of the observed variances. Although genotoxicity was observed in Santo Antônio da Patrulha, the water presented higher mean values for most of the assessed parameters, in the lower stretch, where urbanization and industrialization are greater. The spatial and temporal pattern of water quality observed reinforces the importance of considering the environmental factors and their effects on organisms in an integrated way in watercourse monitoring programs.

Biomonitoring the genotoxic potential of the air on Tradescantia pallida var. purpurea under climatic conditions in the Sinos River basin, Rio Grande do Sul, Brazil.

The present study evaluated the genotoxic effects of the atmospheric air on Tradescantia pallida var. purpurea in urban areas with different intensities of vehicular traffic and in riparian forest fragments in the Sinos River Basin (Rio Grande do Sul, Brazil), considering the influence of climatic conditions prevailing in these environments. Bimonthly, from May 2012 to March 2013, cuttings with flower buds were exposed for 8 h in urban and riparian forest environments in the municipalities of Caraá, Taquara and Campo Bom in the upper, middle and lower sections, respectively, of the Sinos River Basin. Simultaneously, negative controls were made and climatic data were recorded. Micronuclei (MCN) frequencies were determined in young tetrads of pollen mother cells and expressed as MCN/100 tetrads. Significantly higher MCN frequencies were observed in buds exposed in urban and riparian forest environments in Taquara (up to 7.23 and 4.80, respectively) and Campo Bom (up to 4.90 and 4.23, respectively) than in buds exposed in Caraá (up to 2.90 and 2.50, respectively), in the majority of samplings, and in relation to the negative control (up to 1.93) in all months. Over the course of the period monitored, there were significant variations in MCN frequencies at all sampling points, with the exception of the urban environment in Caraá. For the urban environments, relation between the MCN frequency, vehicular traffic and mean temperature was observed. For the riparian forest fragments, there was no association between MCN frequency and climatic factors. Tradescantia pallida var. purpurea can be considered a useful tool to point out areas with increased atmospheric pollution, since the exposure of plants under severe climatic conditions is avoided to minimize their negative influence on the formation of micronuclei.

Biomonitoring the genotoxic potential of the air on Tradescantia pallida var. purpurea under climatic conditions in the Sinos River basin, Rio Grande do Sul, Brazil / Biomonitoramento do potencial genotóxico do ar em Tradescantia pallida var. purpurea sob condições climáticas na bacia do Rio dos Sinos, Rio Grande do Sul, Brasil

Abstract The present study evaluated the genotoxic effects of the atmospheric air on Tradescantia pallida var. purpurea in urban areas with different intensities of vehicular traffic and in riparian forest fragments in the Sinos River Basin (Rio Grande do Sul, Brazil), considering the influence of climatic conditions prevailing in these environments. Bimonthly, from May 2012 to March 2013, cuttings with flower buds were exposed for 8 h in urban and riparian forest environments in the municipalities of Caraá, Taquara and Campo Bom in the upper, middle and lower sections, respectively, of the Sinos River Basin. Simultaneously, negative controls were made and climatic data were recorded. Micronuclei (MCN) frequencies were determined in young tetrads of pollen mother cells and expressed as MCN/100 tetrads. Significantly higher MCN frequencies were observed in buds exposed in urban and riparian forest environments in Taquara (up to 7.23 and 4.80, respectively) and Campo Bom (up to 4.90 and 4.23, respectively) than in buds exposed in Caraá (up to 2.90 and 2.50, respectively), in the majority of samplings, and in relation to the negative control (up to 1.93) in all months. Over the course of the period monitored, there were significant variations in MCN frequencies at all sampling points, with the exception of the urban environment in Caraá. For the urban environments, relation between the MCN frequency, vehicular traffic and mean temperature was observed. For the riparian forest fragments, there was no association between MCN frequency and climatic factors. Tradescantia pallida var. purpurea can be considered a useful tool to point out areas with increased atmospheric pollution, since the exposure of plants under severe climatic conditions is avoided to minimize their negative influence on the formation of micronuclei.

Resumo O presente estudo avaliou os efeitos genotóxicos do ar atmosférico sobre Tradescantia pallida var. purpurea em áreas urbanas com diferentes intensidades de tráfego veicular e em fragmentos de mata ciliar na Bacia do Rio dos Sinos (Rio Grande do Sul, Brasil), considerando a influência de condições climáticas prevalecentes nesses ambientes. Bimensalmente, de maio de 2012 a março de 2013, ramos com botões florais foram expostos por 8 h em ambientes urbanos e de mata ciliar nos municípios de Caraá, Taquara e Campo Bom nos trechos superior, médio e inferior, respectivamente, da Bacia do Rio dos Sinos. Simultaneamente, foram realizados controles negativos e levantados dados climáticos. Frequências de micronúcleos (MCN) foram determinadas em tétrades jovens de células-mãe de grãos de pólen e expressas como MCN/100 tétrades. Frequências de MCN significativamente superiores foram observadas em botões expostos nos ambientes urbanos e de matas ciliares em Taquara (até 7,23 e 4,80, respectivamente) e Campo Bom (até 4,90 e 4,23, respectivamente) do que em botões expostos em Caraá (até 2,90 e 2,50, respectivamente), na maioria das amostragens, e em relação ao controle negativo (até 1,93) em todos os meses. Ao longo do período monitorado, ocorreram variações significativas nas frequências de MCN em todos os pontos amostrais, com exceção do ambiente urbano de Caraá. Para os ambientes urbanos, foi observada relação entre a frequência de MCN, tráfego veicular e temperatura média. Para os fragmentos de mata ciliar, não houve associação entre a frequência de MCN e fatores climáticos. Tradescantia pallida var. purpurea pode ser considerada uma ferramenta útil para apontar áreas com poluição atmosférica aumentada, desde que, sob condições climáticas severas, a exposição das plantas seja evitada, para minimizar o efeito destas sobre a formação de micronúcleos.

Biomonitoring the genotoxic potential of the air on Tradescantia pallida var. purpurea under climatic conditions in the Sinos River basin, Rio Grande do Sul, Brazil

Abstract The present study evaluated the genotoxic effects of the atmospheric air on Tradescantia pallida var. purpurea in urban areas with different intensities of vehicular traffic and in riparian forest fragments in the Sinos River Basin (Rio Grande do Sul, Brazil), considering the influence of climatic conditions prevailing in these environments. Bimonthly, from May 2012 to March 2013, cuttings with flower buds were exposed for 8 h in urban and riparian forest environments in the municipalities of Caraá, Taquara and Campo Bom in the upper, middle and lower sections, respectively, of the Sinos River Basin. Simultaneously, negative controls were made and climatic data were recorded. Micronuclei (MCN) frequencies were determined in young tetrads of pollen mother cells and expressed as MCN/100 tetrads. Significantly higher MCN frequencies were observed in buds exposed in urban and riparian forest environments in Taquara (up to 7.23 and 4.80, respectively) and Campo Bom (up to 4.90 and 4.23, respectively) than in buds exposed in Caraá (up to 2.90 and 2.50, respectively), in the majority of samplings, and in relation to the negative control (up to 1.93) in all months. Over the course of the period monitored, there were significant variations in MCN frequencies at all sampling points, with the exception of the urban environment in Caraá. For the urban environments, relation between the MCN frequency, vehicular traffic and mean temperature was observed. For the riparian forest fragments, there was no association between MCN frequency and climatic factors. Tradescantia pallida var. purpurea can be considered a useful tool to point out areas with increased atmospheric pollution, since the exposure of plants under severe climatic conditions is avoided to minimize their negative influence on the formation of micronuclei.

Resumo O presente estudo avaliou os efeitos genotóxicos do ar atmosférico sobre Tradescantia pallida var. purpurea em áreas urbanas com diferentes intensidades de tráfego veicular e em fragmentos de mata ciliar na Bacia do Rio dos Sinos (Rio Grande do Sul, Brasil), considerando a influência de condições climáticas prevalecentes nesses ambientes. Bimensalmente, de maio de 2012 a março de 2013, ramos com botões florais foram expostos por 8 h em ambientes urbanos e de mata ciliar nos municípios de Caraá, Taquara e Campo Bom nos trechos superior, médio e inferior, respectivamente, da Bacia do Rio dos Sinos. Simultaneamente, foram realizados controles negativos e levantados dados climáticos. Frequências de micronúcleos (MCN) foram determinadas em tétrades jovens de células-mãe de grãos de pólen e expressas como MCN/100 tétrades. Frequências de MCN significativamente superiores foram observadas em botões expostos nos ambientes urbanos e de matas ciliares em Taquara (até 7,23 e 4,80, respectivamente) e Campo Bom (até 4,90 e 4,23, respectivamente) do que em botões expostos em Caraá (até 2,90 e 2,50, respectivamente), na maioria das amostragens, e em relação ao controle negativo (até 1,93) em todos os meses. Ao longo do período monitorado, ocorreram variações significativas nas frequências de MCN em todos os pontos amostrais, com exceção do ambiente urbano de Caraá. Para os ambientes urbanos, foi observada relação entre a frequência de MCN, tráfego veicular e temperatura média. Para os fragmentos de mata ciliar, não houve associação entre a frequência de MCN e fatores climáticos. Tradescantia pallida var. purpurea pode ser considerada uma ferramenta útil para apontar áreas com poluição atmosférica aumentada, desde que, sob condições climáticas severas, a exposição das plantas seja evitada, para minimizar o efeito destas sobre a formação de micronúcleos.

Lead tolerance and accumulation in initial sporophytes of Regnellidium diphyllum Lindm. (Marsileaceae).

Regnellidium diphyllum Lindm. is a heterosporous fern which grows in shallow waters and wetlands, and water pollution contributes to its vulnerability. Environmental lead contamination is mostly caused by industrial and agricultural residues as well as domestic sewage. Given its persistence in the environment, lead can cause important toxicity in living organisms. Megaspore germination and the initial growth of R. diphyllum sporophytes were assessed in Meyer's solution with lead nitrate (Pb(NO3)2) concentrations of 0 (control), 1, 5, 10 and 50 mg L(-1). The study was conducted in a growth chamber at 25 ± 1°C and a 12 hour photoperiod with a nominal irradiance of 100 µmol m(-2) s(-1), for 28 days. Lead concentration in sporophytes was assessed using atomic absorption spectrometry. In the absence of lead, 74% of spores germinated, while significantly lower germination percentages were observed in Pb(NO3)2 concentrations of 1, 10 and 50 mg L(-1). The presence of lead did not significantly influence root growth. At 28 days, primary leaf development was significantly lower in Pb(NO3)2 concentrations of 5 mg L(-1) and higher in relation to the control. The length of secondary leaves did not significantly differ between sporophytes exposed to different concentrations of lead and those of the control at 28 days. Sporophytes exposed to 10 and 50 mg L(-1) Pb(NO3)2 accumulated 1129 mg kg(-1) and 5145 mg kg(-1) of Pb, respectively. The presence of high levels of lead in R. diphyllum sporophytes did not prevent initial development. Future studies should investigate the ability of the species to accumulate and tolerate high levels of lead in advanced stages of its development and in environmental conditions.

Effects of 2,4-D on the germination of megaspores and initial development of Regnellidium diphyllum Lindman (Monilophyta, Marsileaceae).

Regnellidium diphyllum is considered as endangered, occurring in the State of Rio Grande do Sul, Brazil, and a few adjoining localities in Uruguay, Argentina and the State of Santa Catarina. It grows in wetlands frequently altered for agricultural activities. Herbicides based on 2,4-dichlorophenoxyacetic acid (2,4-D) are widely used in these fields. The effects of 2,4-D on the germination of megaspores and initial sporophytic development of R. diphyllum were investigated. Six concentrations of 2,4-D (0.32; 0.64; 1.92; 4.80; 9.60 and 19.20 mg.L-1), and the control (0.00 mg.L-1), were tested in vitro, using Meyer's medium. Cultures were maintained in a growth chamber at 24 +/- 1 degrees C, under artificial light with nominal irradiance of 110 micromol.m-2/s and 16 hours photoperiod. Megaspore germination was lower at 9.60 and 19.20 mg.L-1 of 2,4-D (56 and 48%, respectively), compared with the control (68%). Herbicide concentrations of up to 1.92 mg.L-1 did not significantly decrease the number of sporophytes formed. At 19.20 mg.L-1, no sporophytes were formed. The lengths of the primary root, primary and secondary leaves were greater at concentrations of 0.32 and 0.64 mg.L-1 of 2,4-D. Low concentrations of 2,4-D do not affect germination rates and initial development of R. diphyllum in a significant way. However, higher concentrations (9.60 and 19.20 mg.L-1) affect substantially the germination of the megaspores and interfere with the establishment of the species.