Evidence of protective effects on aquifer recharge from polluted tropical rivers: An analysis of hyporheic meiofauna and sediments

Abstract

Knowledge about the hyporheic zone is important to understand the pollutant attenuation processes that occur during the aquifer recharge, whether by natural or artificial means, for example, Bank Filtration. In this paper, the structure of the hyporheic meiofauna and the influence of pollution, microphytobenthos and sedimentological parameters (grain size, organic matter and CaCO 3 content) were studied at a periurban area of Beberibe River (Northeastern Brazil), the location of a riverbank filtration (RBF) pilot project. PERMANOVA analysis indicated interactions between meiofauna community and the sampling sites, rainfall seasons, and depth. The release of untreated wastewater was the most influential factor for physical and biochemical features of the hyporheic zone, since the sampling sites with higher levels of elements related to eutrophication supported the highest levels of meiofauna abundance, fine sediments, organic matter, and CaCO 3 content. It was verified that organic matter from domestic wastewater in tropical streams can promote protective effects that favor the retention and biodegradation of pollutants in the hyporheic zone. The results reveal that, even in eutrophic rivers, there are factors that contribute to the processes of pollutant attenuation in tropical hyporheic environments. The results demonstrate the potential for using RBF in communities without adequate sanitation, especially in developing countries.

Neglected area of meiobenthos: bibliometric analysis in the status of research on hyporheic meiofauna

“…Freshwater meiofauna has been referred to as an agent that helps improve water quality and hyporheic ecosystem health provider, being even cited as a biological factor in the water filtration process (Hoffmann & Gunkel, 2011;Romero et al, 2014;Gillefalk et al, 2018;Veras et al, 2018;Santos et al, 2021;Freitas et al, 2022). The hyporheic meiofauna purification process is even used in engineering techniques, such as the Riverbank filtration (RBF), which is an alternative method for water treatment that is very efficient and low-cost and makes use of the hyporheic zone to attenuate contaminants and purify water (Veras et al, 2018;Santos et al, 2021;Freitas et al, 2022). Therefore, the influence of these organisms as auxiliary agents in the attenuation of contaminants is clear, making it necessary to conserve these environments.…”

“…Furthermore, these organisms are responsible for bioturbation, in which they excavate the sediment, promoting their mixing. The composition and health can be used as bioindicators of water quality in aquatic environments, where the rapid response of the meiofauna community can reflect environmental disturbances and pollution (Santos et al, 2021;Freitas et al, 2022). Moreover, meiofauna represents an important part of the food web, serving as a source of food for higher and bigger organisms, being the transition of energy between small and large organisms.…”