Jacui River Research Articles

Contaminação dos recursos hídricos por agrotóxicos na região central do Rio Grande do Sul, Brasil

O aumento na utilização de agrotóxicos na agricultura pode trazer graves consequências ao meio ambiente e à saúde da população, que consumir alimentos e água com resíduos de tais substâncias. Desta forma, o presente estudo buscou avaliar a presença e a concentração de agrotóxicos na água para consumo humano e, com isso, compreender os riscos à saúde que a população do município de Cachoeira do Sul está submetida. A metodologia consistiu na coleta e análise de amostras de água, em cinco épocas do ano, entre agosto de 2017 a março de 2018, sendo realizadas duas coletas de água tratada (na estação de tratamento e numa instituição de ensino) e uma de água do rio Jacuí, que abastece a cidade, sendo um total de 15 amostras. As amostras foram submetidas a análise por extração em fase sólida e cromatografia gasosa e líquida acoplada a espectrometria de massas. Os resultados mostraram a presença de resíduos de agrotóxicos em todas as amostras, com período crítico para contaminação entre fevereiro e março. No total, foram identificados 18 princípios ativos de agrotóxicos nas amostras de água, sendo o inseticida imidacloprido o de maior incidência e concentração, seguido pelos herbicidas clomazone e quincloraque. Os poluentes analisados persistiram mesmo após o tratamento da água, expondo a população aos riscos potenciais pela ingestão diária destes componentes. Medidas que promovam a remoção destes compostos na água, bem como alternativas ao modelo agrícola convencional precisam ser desenvolvidas e ampliadas, para promover a redução ou eliminação do uso dos agrotóxicos e proteção da saúde e meio ambiente.

Sustainability Infrastructures in the Coastal Lagoon Waterway of Southern Brazil: Connections to Increase Opportunities in Relation to Nature

O objetivo do artigo é apresentar resultados de pesquisa exploratória sobre a expansão do movimento de cargas na hidrovia na hidrovia Patos - Guaíba - Jacuí e discutir possibilidades de cooperação a partir do aporte de conhecimento, para qualificar tecnicamente esse processo na perspectiva de um desenvolvimento sustentável. Os resultados recolhidos até aqui indicam que empresas que operam cargas no porto de Rio Grande protagonizam um aumento na movimentação utilizando a hidrovia no sistema de águas Patos - Guaíba - Jacuí, na região costeira do Rio Grande do Sul. A pesquisa identifica uma estratégia para enfrentar a perda de cargas para portos de Santa Catarina, em função do custo dos fretes para o modal rodoviário. Outro resultado é a redução das emissões de gases do efeito estufa por unidade de carga. A pesquisa exploratória constata que há sérias dificuldades, dentro de seu modelo administrativo, para que as autoridades portuárias dos portos da hidrovia façam os investimentos necessários à implantação de um sistema de gestão ambiental. Identificam-se também limitações para contar com um bom nível de gerenciamento dos riscos no percurso de navegações por águas de grande extensão, em cenários cambiantes de riscos naturais. A pesquisa utiliza a metodologia da observação participante e se apoia em autores como Sachs para discutir sustentabilidade, Barragán-Muñoz para situar a visão do gerenciamento costeiro, e Hogan, Marandola e Ojima para explorar a questão da vulnerabilidade socioambiental.

<b>Bioassessment using benthic macroinvertebrates of the water quality in the Tigreiro river, Jacuí Basin</b> - doi: 10.4025/actascibiolsci.v35i4.18934

This study aimed to evaluate the water quality in the Tigreiro river, Jacui river Basin, using different approaches. Benthic macroinvertebrates were sampled in July 2010 (winter) and February 2011 (summer) at five sites. In this study were analyzed: microbiological, physical and chemical variables, benthic macroinvertebrates richness and diversity, rapid ecological assessment protocol and benthic biotic indices (% EPT, BMWP’-IAP, ASPT, SOMI). A total of 5,852 individuals were collected belonging to 31 taxa of three Phyla: Annelida, Mollusca and Arthropoda. Chironomidae was the most abundant taxon (63.70%). A reduction in richness, diversity H’ and evenness J’ was observed from the initial stretches to the end stretches of Tigreiro river. The use of different approaches showed that sites in the rural area were less altered. The Tigreiro river was strongly impacted, mainly due to discharge of domestic effluents in the urban area, and the combination of different metrics was useful to detect impacted sites and the consequence for the water quality.

Proveniência dos depósitos de areia do rio Jacuí (RS), utilizando a análise de minerais pesados

Este artigo discute a origem dos depósitos arenosos atuais do rio Jacuí, no sul do Brasil. O Jacuí constitui o principal rio do Estado do Rio Grande do Sul e contém os principais depósitos de areia utilizados na indústria de concreto do estado. O rio Jacuí e seus afluentes drenam as mais diversas áreas-fonte, com diferentes idades e associações litológicas, incluindo as rochas do Escudo Sul-riograndense (Pré-Cambriano), da Bacia do Paraná, onde está incluída a Formação Serra Geral (Cretáceo), e da Formação Tupanciretã (Terciário). As amostras foram coletadas de sedimentos fluviais em transporte para a análise de minerais pesados, ao longo do curso principal do rio e de seus principais afluentes. Os resultados demonstram uma grande diversidade de minerais pesados, incluindo: granada, turmalina, hornblenda, zircão, apatita, estaurolita, opacos (magnetita, ilmenita, hematita e pirita) e, minoritariamente, rutilo, piroxênio (hiperstênio principalmente), cianita, sillimanita, andaluzita, titanita, actinolita e tremolita. Esta assembleia de minerais pesados indica que a área-fonte principal dos sedimentos é o Escudo Sul-rio-grandense, proveniente dos afluentes da margem direita do Rio Jacuí. As rochas sedimentares da Bacia do Paraná também constituem uma importante área-fonte para os sedimentos. As rochas vulcânicas da Formação Serra Geral e as sedimentares fluviais da Formação Tupanciretã fornecem uma menor contribuição. Uma redução pequena, mas consistente, dos índices ATi e GZi ao longo do curso principal do rio, de montante para jusante, indica que os sedimentos sofreram decréscimo destes minerais ao longo da planície aluvial possivelmente devido ao intemperismo. Os valores do índice ZTR e ARi são relativamente constantes ao longo do rio principal. Além disso, o ARi é relativamente baixo. Os valores consistentes destes índices indicam uma forte contribuição dos afluentes do rio Jacuí. A assinatura de minerais pesados do rio Jacuí poderá ser utilizada para avaliar a contribuição dos sedimentos do rio no preenchimento da porção mais jovem da Bacia de Pelotas.

Distribution, habitat and conservation status of two threatened annual fishes (Rivulidae) from southern Brazil

This study presents information on the distribution of Austrolebias cyaneus and A. juan- langi, 2 annual fish species of southern Brazil considered threatened. Furthermore, data are provided on the conservation status of these species and their habitat characteristics to assist in the develop- ment of management plans and in the selection of priority areas for conservation of annual fishes in southern Brazil. A total of 6 populations of A. cyaneus and 3 populations of A. juanlangi were sam- pled from small ponds less than 1000 m 2 in surface area. We sampled 104 specimens of A. cyaneus, distributed in the municipality of Rio Pardo and Minas do Leao in the basins of the Francisquinho, Capivari, and Dom Marcos streams, Jacui River basin. A. juanlangi was recorded in the municipali- ties of Herval, Hulha Negra, and Pedras Altas, Jaguarao River basin, with 53 specimens being cap- tured. At the sampling sites, the main threat to both species was rice cultivation. All pools were altered, isolated, and in an advanced state of degradation as a result of this monoculture. The restricted distribution area of the annual fishes and the advanced state of degradation and habitat loss of the wetlands sampled in this study justify the creation of conservation units in the areas of occurrence of Rivulidae species.

Colonização de substrato artificial pelo mexilhão dourado, Limnoperna fortunei (Dunker, 1857) (Bivalvia, Mytiloida, Mytilidae), no Delta do Rio Jacuí (RS, Brasil)

Colonization of artificial substrate by golden mussel, Limnoperna fortunei (Dunker, 1857), in the Jacui River Delta, Rio Grande do Sul State, Brazil. In order to test a colonization method for Limnoperna fortunei, experiments were carried out in the Jacui River Delta (Rio Grande do Sul State), using wood substrate (X form). The sampling localities are in the Jacui River Delta: Jacui Canal (CJ) and Port Docks (PO). In December (2005), three replicas of substrate were exposed at different depth levels (1; 1.5 and 2m) in each sampling locality (total of 18 replicas). In March, all substrates were collected from the water and transported to the laboratory. The substrates were dehumidified in a Pasteur oven (60°C). The individual adults (> 0.5mm) incrusted on different sides of the substrate (upperside, underside, lateral sides 1 and 2) were removed and quantified under a stereoscopic microscope. The average densities (ind.m-2) and standard errors of golden mussel adults were: CJ, 309.19 ± 30.70 and PO, 39.40 ± 6.00. The Kruskal-Wallis test (α = 0.05) did not present any significant differences between the depth levels (p = 0.715) or substrate sides (p = 0.617). However, the U Test presented differences (p < 0.0001) between sampling localities. The average densities of adult individuals verified in this study were situated between extreme values recorded earlier for wood substrate colonization, i. e. they were higher than those obtained for the Paraguay River and lower than those obtained for the Parana River.

Análise arqueométrica de cerâmica Tupiguarani da região central do Estado do Rio Grande do Sul, Brasil, usando fluorescência de raios X por dispersão de energia (EDXRF)

Energy dispersive X-ray fluorescence methodology (EDXRF) was used to determine Al, Ba, Ca, Cr, Fe, K, Mn, Pb, Rb, S, Si, Sr, Ti, V, Zn in pottery sherds from seven archaeological sites in the central region of Rio Grande do Sul State, Brazil. The potteries' chemical fingerprints from Ijui River, Ibicui Mirim River, Vacacai Mirim River and Jacui River were identified. Interactions between sites from the Jacui River, Vacacai Mirim River and Ibicui Mirim River could have occurred because some samples from these sites are overlapping in a principal component analysis (PCA) graphic. The pottery provenance could be the same.

Estimativa do benefício econômico potencial de dois levantamentos de solos no Estado do Rio Grande do Sul

Este estudo aplica técnicas de análise de decisão para a quantificação do valor econômico do Levantamento de Reconhecimento de Alta Intensidade dos Solos do Município de Sentinela do Sul, RS (escala 1:50.000), e do Levantamento de Solos da Bacia Carbonífera do Baixo Jacuí, RS (escala 1:100.000) através de informações econômicas sobre as culturas regionais e avaliação da qualidade do levantamento de solos. A estimativa do valor econômico é feita pela quantificação do aumento do rendimento econômico quando o planejamento de uso das terras considera as informações contidas no levantamento de solos. Os resultados desta avaliação evidenciam que os benefícios econômicos gerados pelo uso de informações constantes em levantamentos de solos (R$153,15 ha-1 e R$70,15 ha-1, em escala 1:50.000 e 1:100.000, respectivamente) são maiores que os custos associados à execução de levantamentos de solos (R$1,03 ha-1 para um mapa na escala 1:50.000 e R$ 0,38 ha-1 para um mapa na escala 1:100.000).

Análise de agrupamento da vegetação de um fragmento de Floresta Estacional Decidual Aluvial, Cachoeira do Sul, RS, Brasil.

No estado do Rio Grande do Sul, as florestas ripárias se encontram alteradas pela ação antrópica formando fragmentos. O estudo teve como objetivo analisar a estrutura e florística interna dessas florestas o que subsidiará informações para o restabelecimento desses ecossistemas. A área escolhida foi um fragmento (30o04'36"S; 52o53'09"W), de 4 ha, localizada no município de Cachoeira do Sul, RS, no Baixo Rio Jacuí. As espécies arbóreas, arbustivas e lianas (somente quanto à forma de vida) foram inventariadas, utilizando-se faixas perpendiculares ao rio, distanciadas por 50 m, as quais apresentaram 10 m de largura e comprimento que variou com a largura da floresta. As faixas foram divididas em unidades amostrais de 10 x 10 m, nos quais foram identificados indivíduos com circunferência a 1,3m (CAP) 15 cm, registrados os valores de circunferência e altura. Os dados de densidade por espécie formaram uma matriz (70x42) utilizada na análise multivariada. A presença de agrupamentos de espécies no interior do fragmento foi avaliada pelo TWINSPAN (Two-way indicator species analysis), com base no qual foi constatada a existência de três subformações florestais (S-F1, S-F2 e S-F3). A S-F1 foi caracterizada por ter maior influência das enchentes e lençol freático mais próximo da superfície; a S-F2 ocorreu na parte central do fragmento, mas apresentou forte influência dos extravasamentos causados pelas enchentes; e na S-F3, também na porção central, ocorreu maior influência do lençol freático. As espécies indicadoras das subformações foram: Sebastiania commersoniana e Eugenia uniflora (S-F1); Gymnanthes concolor, Cupania vernalis e Seguieria aculeata (S-F2); e Casearia sylvestris e Allophylus edulis (S-F3). Portanto, em projetos de preservação, conservação e restabelecimento desses ecossistemas, a comunidade florestal não pode ser tratada unicamente como ripária, mas considerando as variações ambientais e, conseqüentemente, florísticas.

Estudo da comunidade de larvas de Trichoptera KIRBY, 1813 (Insecta) no curso médio do Rio Jacuí e alguns tributários, RS: Brasil

The present study was carried out with the purpose of determining the taxonomic composition, the diversity, and the spatial and temporal distributions of the Trichoptera larvae community, in four lotic sites at the central region of Rio Grande do Sul State. Sampling was done monthly from Juny 2001 to May 2002 in four sites located at the middle section of Jacui River (Station 4) and in three of its tributaries (Lajeado do Gringo - Station 3; Lajeado da Gringa - Station 2 and Carijinho River - Station 1), with a Surber sampler. Some environmental data were measured (pH, dissolved oxygen, air and water temperature, flow and precipitation). The total number collected was 29,143 specimens, belonging to 25 genera distributed in nine families, 20 of these genera are new records for the State. The highest abundance was found in Station 2 (12,547 specimens). The highest standardized richness, for a 1,151 specimens sample chosen by chance, was recorded in Station 1, followed by Station 4 (17.7 and 15.9 genera, respectively), on the other hand, highest number genera occurred in Stations 1 and 2 (20 genera in each Station), what was due to the influence of sample size on richness. The highest diversity was found in Station 1, and the lowest in Station 3 (H = 1.3 and H = 0.8, respectively). Station 1 had the lowest anthropic influence and the most conserved riparian vegetation; while Station 3 presented the highest anthropic impact, and very reduced riparian vegetation. The diversity of Trichoptera observed in the study site is low, compared to the estimated maximum theoretical diversity. Low diversity values are related to the low equity, since the richness was relatively high. The majority of the environmental factors have not showed significant correlation with genera abundance (p > 0,05), only temperature shown relation with temporal fluctuations of abundance in the majority of Stations. The spatial-temporal distribution, analyzed by the Detrended Correspondence An

Monitoramento e controle de larvas de Culicidae em criadouros artificiais na área da Usina Hidrelétrica de Dona Francisca, Agudo, Rio Grande do Sul

The aim of this work was to monitory and control of the immature mosquitoes around Dona Francisca Hydroelectric (DFH), Agudo, RS. There was a great concern to avoid the introducing of human diseases vectors in this place. Six areas were selected for sampling larva: The hotel swimming pool, the clubhouse near Jacui river, the station of water treatment, the administration square, workers lodgings and tyre fixing places. The collections were taken at three months intervals, during the building period of DFH (June/2000 to February/2001). Lectures were provided for about three thousand people in schools near DFH. No important epidemic species was found, only Aedes fluviatilis and other species of genus Culex, Limatus, and Orthopodomyia. The numbers of artificial breeding places and captured immature mosquitoes decreased throughout the study. There was not significant correlation between the number of mosquitoes captured and the environment factors (temperature, precipitation, and air relative humidity) probably due to the control and decreasing in artificial breeding places.

Contribution to the knowledge of genus Lepocinclis (Euglenophyceae) of the state of Rio Grande do Sul, southern Brazil

Taxonomic survey of representatives of genus Lepocinclis (Euglenophyceae) of a reservoir in the municipality of Triunfo (30°02'15S, 51°13'13 W), state of Rio Grande do Sul, southern Brazil. Samplings were made at 2 stations during 14 consecutive months, from February 1995 to March 1996. Three species, one variety atypical of its respective species, and one atypical taxonomic form were identified. Description of L. salina f. abtusa was complemented on the basis of collections made in four different locations of the Jacui river delta (29°56'S, 51°12'W and 30°03'S, 51°18'W). Lepocinclis salina var. salina was the best represented taxon geographically, occuring throughout the study period and in all net samples collected. Lepocinclis salina var. salina and L. salina f. obtusa were characteristic by their wide tolerance spectrum to the following environmental variables: pH, water temperature, organic matter concentration, total phosphorus, and the nitrogen series (nitrite, nitrate, ammonium, and total nitrogen) concentrations.

Distribution of selected heavy metals in fluvial sediments of the coal mining region of Baixo Jacuí, RS, Brazil

The geochemical distributions of Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were investigated to provide information about the mobility and availability of these elements in polluted sediments from the Baixo Jacui region, southern Brazil. Sediment samples were collected at eight sites in the Conde stream, near coal mining and waste disposal areas, and in the Jacui river, downstream from industrial activities. Total extraction results showed higher metals concentration at some sites, when compared to background values, as well as indicated by the calculated enrichment factor and geoaccumulation index. However, the results were insufficient to establish the existence of anthropogenic contribution to the studied area. The contamination was better evaluated by the sequential extraction. The geochemical distribution in the sediments of the Jacui river revealed the presence of high concentrations of Cr and Cu in the oxidizable fraction, in response to effluent discharge from coal fired power stations and a steel plant. Higher percentages of the available fraction were verified in the Conde stream for the elements Cu, Fe, Ni, Pb, and Zn, indicating the sediment contamination by coal-related activities.

Metacercárias livres de diplostomídeos (Digenea, Diplostomidae) em Loricariichthys anus (Val., 1840) (Siluriformes, Loricariidae) do estado do Rio Grande do Sul, Brasil

Free (unencysted) metacercariae of an undetermined species of digenetic trematode (Diplostomidae) were found over and in the kidney ducts, over the liver, over the peritoneum, in the abdominal cavity and in the brain, but not in the eyes of mailed catfishes, Loricariichthys anus, captured in the coastal lagoons of Peixoto and Pinguela, Osorio, RS; in the channel linking the lagoons, Imbe, RS, and in the Jacui river, Porto Alegre, RS, southern Brazil. The morphology of the metacercariae is described and pictured. They are differentiated from Diplostomum (A.) compactum and D. (A.) mardox for having an acetabulum, being identified, at present, as an undetermined species of the genus Diplostomum. The metacercariae recorded in the present study are also compared with the strigeatoid metacercariae described parasitizing subtropical fishes in Argentina, looking similar to those metacercariae described as Tylodelphylus cardiophilus from the pericardial cavity of the peixe-rei

Gloquídio de Diplodon martensi (lhering) (Mollusca, Bivalvia, Hyriidae) e seu ciclo parasitário

Conchological and anatomical studies of the glochidium of Diplodon martensi (lhering, 1893) were performed on samples collected in a small river, tributary from the Cai River, that belong to the Jacui River sub-basin in south-eastern Brazil. The parasitic development of the glochidium was observed in laboratory on a small cichlid fish Gymnogeophagus gymnogenys (Hensel, 1870).

Captura do Sistema Fluvial Camaquã pelo Sistema Fluvial Jacuí - São Gabriel, RS, Brasil

The analysis of LANDSAT-MSS images and aerial photographs show a capture of headwaters of Camaquã river by Jacui river, at about 54ºW longitude and 31º latitude. This capture occurred 15 km northwest of Lavras do Sul. The area of capture has dimensions of about 30 km2. Elbows of capture and barbed tributaries of the Jacui river provide this evidence and indicate that the Camaquã river was shortened about 6 km. This capture probably has occurred in the Neogene, when erosion is belived to have started in peripheric depression of Rio Grande do Sul. Field work is needed to identify deposits that should provide more clues to the nature and timing of this capture.

Management of Navigation in the Jacui River

ABSTRACT Management of a river system is usually a difficult task due to conflicting water use purposes. The Jacui river (southern Brazil) has a drainage area of 70000 km2, with hydroelectric plants in its upper reach and three navigation dams in the middle and lower reaches. The former dams are used to meet peak power demand, producing great flow variations during weekdays and volume reduction during weekends. The navigation dams do not allow year round navigation due to sediment deposition, low-flow and upstream flow fluctuation. A hydrodynamic model was used to study flow routing, to test operation rules for the navigation dams and to forecast the levels in real time. In this paper, the calibration of the model and the operational criteria to be applied to each of the navigation dams during low-flow periods are presented. The model was calibrated with two recorded events showing maximum errors compatible with the river navigation requirements. Dam operation simulations showed that with the help of the ...

Two-dimensional treatment of dispersion of pollutants in rivers

An experimental work to study the dispersion of non-degradable pollutants in the Jacui river, situated in the south of Brazil, has been performed. 82Br in the form of KBr was used as a tracer material. The experimental results were fitted to a two-dimensional distribution function by which the dispersion coefficients along the river flow, D x , and transverse to it, D y , were found to be 12.4 m 2/ s and 1.7 m 2 s , respectively.