Application of ecological indicators in coastal watershed under high pressure during summer period

Abstract

Water bodies located in coastal areas are subject to human pressures and the loss of environmental quality. The objective of this study was to evaluate the environmental quality of the river Papaquara through water quality and river landscape, using the Trophic Index (TRIX) and Rapid Assessment Protocol (RAP). The study was developed in the watershed located in the north of the island of Santa Catarina, Florianópolis -SC, whose population increase in the summer is around 280%. The Trophic Index and the Rapid Assessment Protocol were evaluated in the pre-summer period, summer and after-summer in seven sample points along the inner areas (higher population density), median and outside the Papaquara river, plus two points in affluent. The river Papaquara showed up in great stress state, is classified as eutrophic, 77% of the samples and changed in 50% of the sampled area, as the TRIX index and RAP, respectively. The internal area registered up eutrophic and impacted in all periods analyzed. The median area and the outer decreased their water quality, due to summer activity, while there was no change in environmental quality by RAP. A significant correlation between the indices used indicated that the RAP should be used with caution to describe the condition of water quality. This analysis has submitted be more appropriate when used in river scale as a whole, but not isolated segments.Keywords: Eutrophication; TRIX; Rapid Assessment Protocol; Papaquara river. RESUMOOs corpos hídricos localizados nas zonas costeiras estão submetidos às pressões antrópicas e a perda da qualidade ambiental. O objetivo deste estudo foi avaliar a qualidade ambiental do rio Papaquara, através da qualidade da água e da paisagem ribeirinha, utilizando-se do Índice Trófico (TRIX) e do Protocolo de Avaliação Rápida (PAR). O estudo foi realizado na bacia hidrográfica localizada no norte da Ilha de Santa Catarina, Florianópolis -SC, cujo aumento populacional no veraneio é em torno de 280%. O Índice Trófico e o Protocolo de Avaliação Rápida foram avaliados nos períodos de pré-veraneio, veraneio e pós-veraneio em sete pontos amostrais ao longo das áreas interna (maior adensamento populacional), mediana e externa do rio Papaquara, além de dois pontos em afluentes. O rio Papaquara mostrou-se em estado de forte estresse, sendo classificado como eutrofizado, em 77% das amostras e alterado em 50% da área amostrada, conforme os índices TRIX e PAR, respectivamente. A área interna apresentou-se eutrófica e impactada em todos os períodos analisados. A área mediana e a externa diminuíram sua qualidade da água, devido a atividade de veraneio, enquanto não houve alteração da qualidade ambiental pelo PAR. A correlação significativa entre os índices utilizados indicou que o PAR deve ser usado com cautela para descrever condição de qualidade da água. Esta análise se apresentou mais adequada quando utilizada na escala do rio como um todo, mas não por segmentos isolados.

Change in the dynamics of salinity and water quality of an island estuary by the discharge of effluents

“…The authors attributed the increase in the fraction of particulate phosphorus to the adsorption processes during saline flocculation and in the resuspension of sediments by the movement of tides. Saline waters of the North Florianopolis Bay have higher oxygen concentrations and lower organic matter (BOD) and nutrient (phosphorus and nitrogen) concentrations when compared to the Papaquara River waters (Simonassi et al, 2010;Silva et al, 2016;Cabral et al, 2020). The inputs of these saline waters improve the water quality along the saline gradient of the estuary, as we can see in Figures 3 and 4, through adsorption and dilution processes.…”

“…15 and 22). Silva et al (2016) registered average concentrations of ammonia nitrogen of 1.8 mg•L −1 in brackish waters at 7.4 km from the mouth of the Papaquara River estuary, the maximum value allowed by the legislation being 0.4 mg•L −1 , configuring the disrespect to the standard. However, if this stretch is reclassified as freshwater class 2, the maximum value allowed would be 3.7 mg•L −1 , considering the pH observed in the stretch by Silva (2015) and Rodrigues (2016), because for fresh waters, CONAMA 357/05 establishes the maximum concentration of ammoniacal nitrogen as a function of pH.…”

“…Thus, WWTPs are essential facilities for mitigating the impacts caused by human settlements (Morrison et al, 2011;Cloern et al, 2016). However, depending on the design characteristics of the WWTP and the carrying capacity of the water environment, effluents can bring negative impacts to their receiving bodies, by raising the organic matter and nutrient loads (Haggard et al, 2005;Silva et al, 2016;Cabral et al, 2019). The input of organic matter and nutrients from anthropogenic sources has been a major problem in estuaries around the world (Kennish, 2002;Cloern et al, 2016;Bianchi, 2007).…”

“…Causing, by eutrophication, the expansion of the occurrence, intensity, and duration of hypoxic conditions in coastal waters worldwide (Testa & Kemp, 2011), resulting in changes in community structure, loss of biodiversity, and modifications in the metabolism of the environment (Diaz & Rosenberg, 2008;Scherner et al, 2013). In many urbanized estuaries, effluents are the main sources of nutrients (phosphorus and nitrogen) and organic matter (Pereira Filho & Rörig, 2016;Silva et al, 2016), directly impacting the functioning of the environment and its uses.…”

Avaliação da sustentabilidade ambiental, social e econômica de uma bacia hidrográfica do semiárido brasileiro

“…Estudos vêm sendo desenvolvidos para avaliar a sustentabilidade de bacias hidrográficas por meio de indicadores ambientais, econômicos e sociais, permitindo a transformação de dados técnicos e complexos em informações de fácil entendimento para o público em geral e para os tomadores de decisões (Heink & Kowarik, 2010;Tscherning et al, 2012;Maes et al, 2016;Silva et al, 2016). Estes indicadores podem ser utilizados no arcabouço teórico DPSIR (Driving forces -Forças Motrizes; Pressures -Pressões, State -Estado; Impacts -Impactos e Responses -Respostas), que foi proposto pela Organização de Cooperação Econômica e Desenvolvimento, visando auxiliar principalmente nas decisões referentes à conservação ambiental de bacias hidrográficas (OECD, 1993;Liu et al, 2019).…”