Mixed effects of effluents from a wastewater treatment plant on river ecosystem metabolism: subsidy or stress?

Abstract

SUMMARY1. The effluents of wastewater treatment plants (WWTPs) include a complex mixture of nutrients and pollutants. Nutrients can subsidise autotrophic and heterotrophic organisms, while toxic pollutants can act as stressors, depending, for instance, on their concentration and interactions in the environment. Hence, it is difficult to predict the overall effect of WWTP effluents on river ecosystem functioning. 2. We assessed the effects of WWTP effluents on river biofilms and ecosystem metabolism in one river segment upstream from a WWTP and three segments downstream from the WWTP and following a pollution gradient. 3. The photosynthetic capacity and enzymatic activity of biofilms showed no change, with the exception of leucine aminopeptidase, which followed the pollution gradient most likely driven by changes in organic matter availability. The effluent produced mixed effects on ecosystem-scale metabolism. It promoted respiration (subsidy effect), probably as a consequence of enhanced availability of organic matter. On the other hand, and despite enhanced nutrient concentrations, photosynthesis-irradiance relationships showed that the effluent partly decoupled primary production from light availability, thus suggesting a stress effect. 4. Overall, WWTP effluents can alter the balance between autotrophic and heterotrophic processes and produce spatial discontinuities in ecosystem functioning along rivers as a consequence of the mixed contribution of stressors and subsidisers.

Evaluating the Impact of Wastewater Effluent on Microbial Communities in the Panke, an Urban River

“…The DOC in the Panke river was in accordance with the results of Aristi et al [40], who found higher DOC values near a WWTP which decreased with increasing distance to the plant, and a several-fold increase in the DOC concentration caused by a WWTP effluent was also observed by Ruggiero et al [41]. In our study, higher DOC concentrations were found mainly at the PuBG and the PoBG site, within the summer campaign 2017.…”

Bioaccumulation and trophic magnification of pharmaceuticals and endocrine disruptors in a Mediterranean river food web

“…Thus, variation (over time) in the number and concentration of compounds found in water would have likely altered BAFs if a longer time window had been considered. However, levels found in river water were close to those found in the same site but in a different period of the year , and another study showed that the concentrations of some pharmaceuticals in these study reaches were relatively stable over a 48-h period (Aristi et al, 2015). Overall, our study advances the notion that both waterborne and dietary exposure may contribute to the bioaccumulation of emerging pollutants in aquatic organisms.…”

Potential biotechnological capabilities of cultivable mycobiota from carwash effluents

“…Numerous studies have reported the existence of fungi in pollution‐stressed and extreme environments (Aguilera, ; Aristi et al., ; Cantrell, Casillas‐Martínez, & Molina, ; Cantrell et al., ). Aspergillus , Penicillium , Curvularia , Fusarium , Microsporum , Trichoderma , Rhizoctonia , Nigrospora , and Chaetophoma have previously been isolated from raw refinery effluents (Machido, Yakubu, & Ezeonuegbu, ).…”