Mapping Micro-Pollutants and Their Impacts on the Size Structure of Streambed Communities

Abstract

Recently there has been increasing concern over the vast array of emerging organic contaminants (EOCs) detected in streams and rivers worldwide. Understanding of the ecological implications of these compounds is limited to local scale case studies, partly as a result of technical limitations and a lack of integrative analyses. Here, we apply state-of-the-art instrumentation to analyze a complex suite of EOCs in the streambed of 30 UK streams and their effect on streambed communities. We apply the abundance-body mass (N-M) relationship approach as an integrative metric of the deviation of natural communities from reference status as a result of EOC pollution. Our analysis includes information regarding the N and M for individual prokaryotes, unicellular flagellates and ciliates, meiofauna, and macroinvertebrates. We detect a strong significant dependence of the N-M relationship coefficients with the presence of EOCs in the system, to the point of shielding the effect of other important environmental factors such as temperature, pH, and productivity. However, contrary to other stressors, EOC pollution showed a positive effect on the N-M coefficient in our work. This phenomenon can be largely explained by the increase in large-size tolerant taxa under polluted conditions. We discuss the potential implications of these results in relation to bioaccumulation and biomagnification processes. Our findings shed light on the impact of EOCs on the organization and ecology of the whole streambed community for the first time.2 of 12 affect all levels of biological organization [9]. However, characterization and quantification of EOCs in riverine systems is still limited, as is our understanding of their relationship with environmental gradients, especially at large spatial scales [4]. This is largely because determining low concentrations of these substances can be a challenge using existing analytical methodologies [12]. Consequently, most EOCs have been determined to be low risk due to low environmental concentrations [13], and their effect on natural systems is largely unknown.Most anthropogenic effluents are discharged to surface streams and rivers where water is exchanged between the open channel and the saturated permeable streambed sediments [14]. Consequently, dissolved EOCs penetrate the sediments, and organisms located here may be exposed to the effects of EOCs for longer periods of time because of the extended residence times of water in the pore-spaces [15,16]. Streambed sediments harbor diverse and productive biological consortia, whose components range from prokaryotes and microscopic single cell eukaryotes (e.g., flagellates and ciliates) through to meio-and macrofauna (rotifers, copepods, and insect larvae). This translates into a great diversity of life strategies and adaptation capabilities, and, consequently, understanding the effect of EOCs on the whole streambed assemblage is challenging. For example, it might be expected that the rapid population growth and adaptation capacity of prokaryotes might result...

Simultaneous attenuation of trace organics and change in organic matter composition in the hyporheic zone of urban streams

“…Urban streams are impacted by high loads of nutrients and contaminants 1 such as trace organic compounds (TrOCs). The widespread occurrence of TrOCs threatens the quality of drinking water resources 2 – 4 and alters freshwater ecosystems 5 , 6 .TrOCs enter urban waters, besides other pathways, especially with discharge of treated wastewater 7 . In addition to TrOCs, effluents of wastewater treatment plants (WWTP) contain elevated loads of organic matter 8 .…”

Putting the “Beaver” Back in Beverley Brook: Rapid Shifts in Community Composition following the Restoration of a Degraded Urban River

“…data.gov.uk/catchment-planning/OperationalCatchment/3032/classifications (accessed on 25 November 2021)), and like most rivers in urbans settings, stormwater runoff is a major source of river degradation [50]. In a recent study, Beverley Brook had the greatest number of emerging organic contaminants across 30 UK streams studied [51]. Some improvements in water treatment have been carried out in the time since restoration was carried out (personal communication), which may help to account for the improvements in invertebrate richness in the control sites three years after restoration although invertebrate density generally declined over the same time period.…”

Streambed pollution: A comprehensive review of its sources, eco-hydro-geo-chemical impacts, assessment, and mitigation strategies

“…The new evolving category of emerging contaminants within streambeds induce toxicity, reduce dissolved oxygen content, and hinders photosynthesis posing serious threat to the existence of microbiota and dependent aquatic ecosystems [24,89]. Richmond et al (2017) [183] documents literature examples to demonstrate the serious eco-biological consequences of pharmaceutical contaminants even at low or miniscule concentrations.…”

“…Further, a new class of chemical pollutants called as emerging contaminants (e.g. micro-plastics, personal-care products and pharmaceutical compounds) are being observed in streambeds, which have more detrimental health risks to humans as well as the fluvial ecosystems [23,24,25]. Biological pollutants, such as Escherichia coli and Coliform, have a profound impact on the microbial quality of stream water [26].…”