Linking ecological health to co-occurring organic and inorganic chemical stressors in a groundwater-fed stream system

Published on Nov 1, 2018in Science of The Total Environment5.59
· DOI :10.1016/j.scitotenv.2018.06.119
Anne Th. Sonne1
Estimated H-index: 1
(DTU: Technical University of Denmark),
Jes J. Rasmussen18
Estimated H-index: 18
(AU: Aarhus University)
+ 3 AuthorsUrsula S. McKnight3
Estimated H-index: 3
(DTU: Technical University of Denmark)
Abstract Freshwaters are among the most endangered ecosystems worldwide, due predominantly to excessive anthropogenic practices compromising the future provisioning of ecosystem services. Despite increased awareness of the role of multiple stressors in accounting for ecological degradation in mixed land-use stream systems, risk assessment approaches applicable in field settings are still required. This study provides a first indication for ecological consequences of the interaction of organic and inorganic chemical stressors, not typically evaluated together, which may provide a missing link enabling the reconnection of chemical and ecological findings. Specifically, impaired ecological conditions – represented by lower abundance of meiobenthic individuals – were observed in the hyporheic zone where a contaminant groundwater plume discharged to the stream. These zones were characterized by high xenobiotic organic concentrations, and strongly reduced groundwater (e.g. elevated dissolved iron and arsenic) linked to the dissolution of iron hydroxides (iron reduction) caused by the degradation of xenobiotic compounds in the plume. Further research is still needed to separate whether impact is driven by a combined effect of organic and inorganic stressors impacting the ecological communities, or whether the conditions – when present simultaneously – are responsible for enabling a specific chemical stressor's availability (e.g. trace metals), and thus toxicity, along the study stream. Regardless, these findings suggest that benthic meioinvertebrates are promising indicators for supporting biological assessments of stream systems to sufficiently represent impacts resulting from the co-occurrence of stressors in different stream compartments. Importantly, identification of the governing circumstances is crucial for revealing key patterns and impact drivers that may be needed in correctly prioritizing stressor impacts in these systems. This study further highlights the importance of stream-aquifer interfaces for investigating chemical stressor effects in multiple stressor systems. This will require holistic approaches for linking contaminant hydrogeology and eco(toxico)logy in order to positively influence the sustainable management of water resources globally.
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#1Frederico Guilherme de Souza Beghelli (UNESP: Sao Paulo State University)H-Index: 4
#2Julio C. López-Doval (USP: University of São Paulo)H-Index: 14
Last.Viviane Moschini Carlos (UNESP: Sao Paulo State University)H-Index: 3
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#1Ignacio Peralta-Maraver (University of Roehampton)H-Index: 3
#2Julia Reiss (University of Roehampton)H-Index: 14
Last.Anne L. Robertson (University of Roehampton)H-Index: 13
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#1Anne Thobo Sonne (DTU: Technical University of Denmark)H-Index: 3
#2Ursula S. McKnight (DTU: Technical University of Denmark)H-Index: 3
Last.Poul Løgstrup Bjerg (DTU: Technical University of Denmark)H-Index: 44
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#1Nicola Balbarini (DTU: Technical University of Denmark)H-Index: 5
#2Wietse M. Boon (University of Bergen)H-Index: 4
Last.Philip John Binning (DTU: Technical University of Denmark)H-Index: 29
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