Impact assessment of an effluent discharge on benthic macroinvertebrates in a subtropical river using indexes

Benthic macroinvertebrates are used as environmental bioindicators in the assessment of water quality in rivers and lakes, due to the sensitivity of some taxa to pollution. The objective of this research was to evaluate the consequences of industrial effluent discharge on the structure of the benthic community present in a river in the subtropical region of Brazil. The organisms were collected at three points of the Coutinho River, in 2013 (September and November) and 2014 (January and March). To characterize the community were calculated density, Shannon diversity index (H ́), Pielou equitability (J), taxa richness, Biotic Indices (Biological Monitoring Working Party - BMWP, Average Score Per Taxon - BMWP-ASPT, Family Biotic Index – FBI) and Canonical Correspondence Analysis (CCA) between sampling points and biotic and abiotic variables. Fifteen taxa were identified and among the collected organisms, the family Chironomidae was the most representative, followed by Oligochaeta, Hirudinea, Bivalvia, Gastropoda. According to the results of the biological indices, point 1 indicated moderate pollution and the following points (2 and 3) showed severe pollution. These indices showed poor waters with a high degree of pollution. The results were efficient in detecting the environmental impacts suffered by the river and suggest the necessity of a continuous monitoring of the same.

Distribution and diversity of aquatic insects of Vellayani lake in Kerala.

The diversity of insect fauna of Vellayani lake in Kerala was represented by 60 species classified under 37 families and 8 orders. Among the entomofauna collected from the lake, the order Coleoptera was diverse in number of genera (22). Shannon index was highest in station 2 (3.214) and lowest (2.839) in station 4. The higher richness index was also recorded in station 2 (6.331), though the lowest species richness was observed in Station 1 (5.205). The order Ephemeroptera is represented in Vellayani lake by the families Baetidae and Caenidae, which are considered as an indicator of water quality. Of the 15 metrices selected, taxa richness, Composition measures, Tolerance and Intolerance and Functional groups were also found out for all the stations. In the present study, the percentage of Ephemeroptera, Plecoptera, Trichoptera (EPT) taxa richness and diversity remained high in Station 1, 2 and 3 but reduced drastically in stations 4 and 5. The high HBI value recorded at station 4 is due to the abundance of pollution tolerant taxa such as Chironomidae, Tabanidae, Culicidae and Anophilinae. The results of the study reveal greater diversity of aquatic entomofauna in Vellayani freshwater lake and suggest the possibility of using insects effectively for biomonitoring programmes.

A comparative analysis of biotic indices that use macroinvertebrates to assess water quality in a coastal river of Paraná state, southern Brazil / Análise comparativa de índices bióticos de avaliação de qualidade de água, utilizando macroinvertebrados, em um rio litorâneo do estado do Paraná, sul do Brasil

Biotic indices to monitor water quality are helpful tools for evaluating the health of rivers and lakes. In Brazil water samples are mainly analyzed using physical and chemical attributes, because most biotic indices were developed in other countries and their effective application to Brazilian ecosystems requires significant research. This study compared four biotic indices commonly used to evaluate water quality via benthic macroinvertebrates in order to determine which index best reflects ecosystem health in a coastal river in Brazil's Paraná state. We also analyzed functional feeding groups. The indices studied were: 1) EPT (percent of Ephemeroptera, Plecoptera and Trichoptera); 2) BMWP' (Biological Monitoring Work Party System); 3) BMWP'-ASPT (Average Score per Taxon); and 4) HFBI (Hilsenhoff Family Biotic Index). All indices were calculated from five samples collected from April 2005 to April 2006 at two stations on the coastal do Pinto River. The river's headwaters are inside a protected area but impacts increase downriver (e.g., towns, cattle grazing, tourism). The HFBI index did the poorest job of reflecting water quality. No one index performed better than the others, and all indices yielded water quality scores that did not accurately reflect macroinvertebrate community structure because all of them had differences between ordination scores and the structure of assemblage. The functional feeding groups protocol classified the lower stretch of the river as disturbed due to human impacts, suggesting that this method is a good one to evaluate health in environments.

A utilização de índices bióticos como ferramenta para o biomonitoramento da qualidade de recursos hídricos tem sido eficaz no diagnóstico de rios e lagos. As variáveis utilizadas atualmente para o monitoramento da qualidade de água são de caráter biológico, físico e químico. Os índices bióticos aplicados no país são de origem estrangeira na sua maioria, não sendo, portanto, totalmente representativos dos ecossistemas regionais. É preciso testar a eficiência destes índices bióticos nas nossas ecorregiões. Este estudo teve como objetivo fazer uma análise comparativa entre quatro índices bióticos de avaliação da qualidade de água utilizando a macrofauna de invertebrados bentônicos com o intuito de diagnosticar o índice mais indicado para os rios litorâneos no Paraná, bem como caracterizar o ambiente e avaliar sua saúde ambiental por meio da utilização de análises dos grupos de alimentação funcional. Para isso foram selecionados quatro índices bióticos: 1) EPT INDEX (Porcentagem de Ephemeroptera, Plecoptera e Trichoptera); 2) BMWP' (Biological Monitoring Work Party System); 3) BMWP'-ASPT (Average Score per Taxon); e 4) HFBI (Hilsenhoff Family Biotic Index), que foram aplicados em dois trechos de um rio litorâneo do Estado do Paraná. O rio do Pinto nasce em área preservada e recebe ao longo de seu curso uma série de despejos, sejam de origem doméstica, agrícola ou de atividade de lazer. Foram feitas cinco amostragens entre abril de 2005 e abril de 2006 em dois pontos distintos do rio do Pinto, Morretes (PR). Foi constatado que dos índices bióticos, o HFBI é o que menos reflete as condições de qualidade de água e não há um índice biótico mais recomendado, uma vez que todos apresentam discrepâncias entre os escores obtidos e a estrutura da composição faunística. O protocolo de grupos de alimentação funcional revela um rio desestruturado na porção a jusante que se encontra sob influência antrópica, sugerindo ser este um método eficiente de diagnóstico de ambientes.