Abstract

In stream ecosystems, microbes and macroinvertebrates consume leaf litter deposited from the riparian vegetation, and thereby recycle resources tied up in the litter. Several environmental variables influence rates of this recycling, but it is not well known if common pharmaceuticals, such as antihistamines, originating from waste-water effluent, have additional impacts. Exposure to dilute concentrations of antihistamines may adversely influence aquatic detritivorous invertebrates, because invertebrates use histamines for neurotransmission, resulting in hampered recycling of resource tied up in leaf detritus. In this study, we therefore investigated if the antihistamine fexofenadine, at a concentration of 2000 ng l(-1), alters rates of leaf litter decomposition in stream microcosms. Stonefly larvae (n = 10, per microcosm), together with natural microbial communities, served as main decomposer organisms on alder leaf litter. First, we used 30 microcosms containing fexofenadine, while the other 30 served as non-contaminated controls, and of each 30 microcosms, 14 contained stonefly larvae and microbes, while the remaining 16 contained only microbes. We found, in contrast to our hypothesis, that fexofenadine had no effect on leaf litter decomposition via impacts on the stonefly larvae. However, independent on if stoneflies were present or not, concentrations of organic carbon (TOC) and nitrogen (N) were strongly affected, with 20-26 and 24-31% lower concentrations of TOC and N, respectively, in the presence of fexofenadine. Second, in a scaled down follow-up experiment we found that microbial activity increased by 85%, resulting in a 10% decrease in pH, in the presence of fexofenadine. While the antihistamine concentration we used is higher than those thus far found in the field (1-10 ng l(-1)), it is still 100 times lower than the predicted no-effect concentration for fexofenadine. As such, our results indicate that low mu g l(-1) levels of antihistamines can have an effect on carbon and nutrient recycling in aquatic system. (C) 2015 Elsevier B.V. All rights reserved.

Keywords

Aquatic insects; TOC; Fexofenadine; Nitrogen; Pharmaceuticals; Stonefly

Published in

Science of the Total Environment
2015, Volume: 538, pages: 240-245
Publisher: ELSEVIER SCIENCE BV

UKÄ Subject classification

Environmental Sciences


Publication identifier

DOI: https://doi.org/10.1016/j.scitotenv.2015.08.061

Permanent link to this page (URI)

https://res.slu.se/id/publ/119842