Eduardo A. Lobo

Association of periphytic diatom species of artificial substrate in lotic environments in the Arroio Sampaio Basin, RS, Brazil: relationships with abiotic variables

Associations of diatom species were identified, in the Arroio Sampaio Basin, Rio Grande do Sul, Brazil, based on monthly samplings over a year along Arroio Sampaio and its main tributaries, using polyamide thread as an artificial substrate. The species groupings showed four different environments: medium-lower course of Arroio Sampaio; and lower course of Arroio Teresinha; upper course of Arroio Sampaio; and lower course of Arroio Duvidosa. Among the physical and chemical variables measured, water pollution, particularly organic contamination and eutrophication, measured from BOD, and total phosphate concentration, respectively, appeared to be one of the most important environmental factors determining the composition and structure of species associations in the area studied.

Toxicity and genotoxicity of hospital laundry wastewaters treated with photocatalytic ozonation.

The aim of the present study was to assess the efficiency of advanced oxidative processes based on photocatalytic ozonation (O(3), UV, UV/O(3), UV/O(3)/Fe(2+) 50 mg L(-1) and 150 mg L(-1)) in the treatment of hospital laundry wastewaters. The analysis of the investigated wastewater revealed high chemical oxygen demand (COD - 3343.8 mg L(-1)), biochemical oxygen demand (BOD(5) - 1906.4 mg L(-1)), total Kjeldahl nitrogen (TKN - 79.8 mg L(-1)) and Daphnia magna toxicity (EC50=1.73). Genotoxic effects were also detected for Allium cepa. Reductions of some parameters occurred after photocatalytic ozonation. The UV/O(3)/Fe(2+) 150 mg L(-1) method was more efficient in reducing COD (59.1%), BOD(5) (50.3%) and TKN (86.8%). There was significant reduction (p<0.05) in D. magna toxicity, O(3) (EC50=47.3%), UV (EC50=50.6%) and UV/O(3)/Fe(2+) 150 mg L(-1) (EC50=45.4%) processes. Normalization of the mitotic index and reduction of micronucleated cells were observed in A. cepa after the treatments. Results demonstrate that these methods were efficient in the degradation of hospital laundry wastewaters, representing a thriving alternative for the removal of pollutants that cause toxicity and genotoxicity.

Análise da estrutura de comunidades fitoplanctônicas e de alguns fatores abióticos em trecho do Rio Jacuí, Rio Grande do Sul, Brasil

Sao apresentados os resultados do estudo do fitoplâncton e de algumas variaveis fisicas e quimicas da agua em um trecho do Rio Jacui, com base em amostragens realizadas em julho de 1986. As coletas foram efetuadas em tres seccoes do rio, incluindo, alem da area de influencia direta de efluentes industriais, ricos em residuo de carvao mineral, uma seccao anterior e outra posterior as industrias, visando a uma avaliacao ambiental preliminar. Foram registrados 130 taxons de microalgas, sendo que seis constituem-se em primeira citacao de ocorrencia para o Estado. Destacaram-se as Bacillariophyta, as Chlorophyta e as Cyanophyta, quanto a densidade celular. Alteracoes na estrutura das comunidades fitoplanctonicas e em fatores abioticos do sistema, esperadas como decorrencia da poluicao industrial e orgânica local, nao foram comprovadas, pois os valores de diversidade especifica do fitoplâncton, bem como de algumas variaveis fisicas e quimicas analisadas, nao apresentaram diferencas significativas para as seccoes estudadas, devido, provavelmente, ao alto poder de diluicao do Jacui, em decorrencia de sua vazao.

Análise da estrutura da comunidade de diatomáceas (Bacillariophyceae) em duas estações do sistema Guaíba, Rio Grande do Sul, Brasil

Atraves da analise da composicao especifica e da diversidade da comunidade de diatomaceas, em duas estacoes do sistema Guaiba (RS, Brasil), nos meses de setembro e novembro de 1975, foi encontrada uma diferenca significativa na estrutura dessa comunidade. Essa diferenca deve-se, provavelmente, a presenca exclusiva de Achnanthes inflata (Kutz.) Grun. var. elata (Leud. - Fort.)Hust., A. lanceolata (Breb.)Grun. var. lanceolata, Cocconeis placentula Ehr., Cyclotella meneghiniana Kutz., Cymbella minuta Hilse ex Rabh., Aulacosira distans (Ehr.) Sim., Navicula mutica Kutz., Surirella robusta Ehr. var. splendida (Ehr.) Van Heurck, Synedra ulna (Nitz.)Ehr., especies abundantes, que refletem caracteristicas ambientais distintas, pelo fato de apresentarem uma diferenciacao em suas tolerâncias ecologicas. Foram identificados um total de 114 taxons, 57 a niveis especificos e infra-especificos, dentre os quais 14 constituem-se em primeira referencia para o Guaiba e quatro sao citacoes novas para o Estado.

Gênero Strombomonas Deflandre (Euglenophyceae pigmentadas em ambiente lótico subtropical, município de Triunfo, RS, Brasil: riqueza e distribuição geográfica

A taxonomic study of the genus Strombomonas Defl. was carried out in three reaches of the stream Bom Jardim, Municipality of Triunfo, Rio Grande do Sul State, expanding the knowledge of its richness and geographical distribution. Samples were collected monthly (2002-2006), with plankton net and preserved with formaldehyde. Simultaneously, water samples for measurement of physicochemical variables were collected. Twenty-six species of Strombomonas were identified; eight taxa have cosmopolitan distribution and the remainder are restricted to a maximum of three continents. The cluster analysis indicated that the greatest similarity occurred between the stream sections T2 and T3, equal to 82%, differently from T1 (upper reaches). This difference can be explained considering that in T1 the exclusive presence of the species S. brevicaudata,S. scabra var. labiata, and S. rotunda was verified. Strombomonas brevicaudata Conf. is registered for the first time in the State. Strombomonas eurystoma (Stein) f. incurva (Buz.) Pop., and S. recurvata Conf. & Joo are new records for Brazil.

Evaluation of water and sediment quality of urban streams in Santa Cruz do Sul County, RS, Brasil, using ecotoxicological assays

AIM: This study aimed to assess the quality of water and sediment of urban streams (Lajeado, Preto, Pedras and Lewis-Pedroso) located in Santa Cruz do Sul County, RS, Brazil, using the microcrustacean Ceriodaphnia dubia as test-organism. METHODS: Quarterly scientific excursions to the streams were held on August and November 2011, February and May of 2012 in order to collect water and sediment samples, in the upper reaches (P1, P3, P5, P7) and lower reaches (P2, P4, P6, P8), totalizing 8 points. To evaluate the toxicity (acute and chronic), the microcrustacean C. dubia was used. RESULTS AND CONCLUSION: The results indicated high toxicity levels detected in samples P2, P6 and P8 (lower reaches), as they caused the mortality of 100% of organisms in the water samples (P6 and P8) and sediment samples (P2 and P8), denoting acute effect. Yet, all upstream sites showed chronic effects in sediment samples, at least for one collection period, with the highest significant toxicity level among all samples (55.2%), which indicates the presence of contamination even in upper areas. These results indicated a strong degradation of the water and sediment quality of urban streams coming from the wastewater and industrial discharges of the urban area, which can cause damage to the biota as well as the public health, due to the multiples uses of water that the local population does, highlighting many of them as inappropriate to the water quality detected, such as the primary contact recreation (balneability).

Constructed Wetlands Integrated with Advanced Oxidation Processes in Wastewater Treatment for Reuse

The development of integrated systems for wastewater treatment has been investigated in recent years not only for the improvement of control parameters but also to allow the routine reuse of wastewater to be effectively implemented. Several studies also seek to add processes that may reuse by-products, energy, and unit operations in a single integrated remediation unit. Considering the sustainability scenario, all these processes should be designed and controlled with description of scope, mass inventory, and energy demand in order to establish indexes of environmental pressure. Classical publications of books and articles for wastewater treatment have already described to more than 10 years several procedures and standards for reuse (direct or indirect), segregation at source, required treatment levels, groundwater recharge, combination of remediation processes, logistics, and sanitation. In this case, further investigation to decentralized systems, such as reed bed filters, with reduced costs of implementation and operation is required, as well as the simplicity of units to be installed. This tendency of integrated phytoremediation systems supports the growing interest for the combination of a system already considered classic in wastewater treatment, the constructed wetlands (CWs), with advanced oxidation processes (AOPs), particularly the photocatalysis with direct or indirect use of solar energy. Because of its already reported disinfection and detoxification potentials which might enable the reuse of urban wastewaters for some specific purposes, the photocatalytic treatment was selected for a study of case. So, this chapter covers the phenological aspects of a macrophyte still little used in phytoremediation, the Hymenachne grumosa; the evolution of the combined use of Upflow Anaerobic Sludge Blanket systems (UASB) + CWs; and the integration of the processes UASB + CWs + UV /TiO2/O3 with indirect use of solar energy in photoreactors designed for these studies.

Response of epilithic diatom communities to environmental gradients along an Ecuadorian Andean River

Epilithic diatom communities are particularly suitable for the evaluation of freshwater quality. In Ecuador, however, no water quality index includes this biotic parameter. This work is the first attempt in the country to determine the composition of epilithic diatom communities associated with different degrees of eutrophication. This was accomplished by measuring physical, chemical and microbiological variables at five sampling sites along the Pita River, Ecuador, from August to December 2016. The results indicate a clear gradient of eutrophication from sampling sites P1 (good water) in the upper reaches to P5 (bad water) located in the lower reaches. Concerning diatom analyses, the results indicated a high diversity for tropical areas in terms of species richness, varying from S=34 in headwaters to S=42 downstream. Moreover, the results obtained suggest a lack of concordance with the trophic values given to some of the epilithic diatoms in the literature. There were also species that seem to be sensitive to downstream nutrient increases that were not considered as bioindicators in previous studies. We concluded that the trophic values of diatom species available in the scientific literature are not directly applicable to their sites in the Pita River. Hence, it is necessary to establish a trophic diatom index for the Andean region of Ecuador.

Desfluoretação de águas subterrâneas por adsorção e precipitação por contato em carvão ativado de osso

A ingestao de fluor em excesso via agua potavel destaca-se como problema de saude publica. O fluor em concentracoes adequadas (6-9 mg L-1) atua na prevencao da carie dental, entretanto, em quantidades acima do estabelecido pela portaria 2914/2011 do Ministerio da Saude (1,5 mg L-1), causa fluorose dental. Assim, o principal objetivo deste trabalho foi o desenvolvimento de um prototipo para desfluoretacao de aguas subterrâneas, utilizando carvao ativado de osso como meio adsorvente. Apos saturacao, foram adicionados sais de calcio e fosforo para auxiliar na desfluoretacao. O sistema foi construido utilizando um tanque de adsorcao preenchido com 235 kg de carvao ativado de osso, tendo uma concentracao de fluoretos entre 2,1 e 3,7 mg L-1. O sistema foi operado com vazao entre 600 a 1.000 L h-1 tratando 410.535 litros de agua, destacando que o nivel de fluoretos na agua foi ≤ 1,5 mg L-1. As vazoes das solucoes de cloreto de calcio (4 g L-1) e dihidrogeno fosfato de potassio (4 g L-1) foram aproximadamente de 1,3 e 2,0 L h-1, respectivamente. Os resultados demonstraram que a tecnica de precipitacao por contato destaca-se como uma alternativa viavel para o desenvolvimento de sistemas de desfluoretacao de agua para consumo humano.

LEVANTAMENTO DA FAUNA SILVESTRE ATROPELADA NA BR 290 (KM 210 a 214), MUNICÍPIO DE PANTANO GRANDE, RS, BRASIL

A construcao de rodovias e um dos fatores que contribui para a fragmentacao original do habitat da fauna silvestre causando uma barreira ao fluxo genico de especies. Desta forma, o monitoramento da fauna atropelada nas estradas se tornou uma ferramenta importante para determinar a perda da biodiversidade faunistica, revelando aspectos da forma de deslocamento e dinâmica sazonal de populacoes de algumas especies. Neste contexto, o objetivo do estudo foi monitorar os atropelamentos da fauna silvestre na BR 290, entre os Km 210 a 214, municipio de Pântano Grande, RS. O inventario de campo foi realizado durante o periodo de 1 ano, entre dezembro de 2013 a dezembro de 2014, percorrendo a rodovia atraves de caminhadas uma vez ao dia geralmente pela manha. O criterio utilizado foi contabilizar todos os animais vertebrados que estavam atropelados por veiculos automotores que trafegaram na rodovia. As especies foram identificadas no local pela morfologia externa, sendo as ocorrencias documentadas utilizando câmera fotografica. Os resultados indicaram que a classe melhor representada foi o grupo das Aves com 46,5%, seguido da classe Mammalia com 24,1%, Reptilia com 23,2% e Amphibia com 6,1%. Dentre a fauna ameacada de extincao, registrou-se a especie Tamandua tetradactyla (tamandua-mirim), que se encontra na categoria vulneravel para o Estado do Rio Grande do Sul. Atraves do inventario dos animais silvestres atropelados, foi verificada uma perda da biodiversidade relacionada a fauna local, com 228 animais mortos durante o periodo da pesquisa. Neste sentido, visando a preservacao da diversidade biologica, e consequente banco genetico animal, torna-se necessario a adocao de medidas mitigatorias para conter este impacto a fauna local.