Assessing toxicity of contaminants in riverine suspended sediments to freshwater mussels

Abstract

The Clinch River in Virginia and Tennessee, USA, is well known for its diverse native freshwater mussel assemblages; however, notable declines in mussel populations in recent decades have prompted much concern and subsequent research. We examined the toxicity of recently-deposited sediments on juveniles of the freshwater mussel Epioblasma brevidens, by collecting time-integrated sediment samples from the water column with sediment traps from 11 sites in the Clinch River Basin, including 6 sites within an 88-km reach deemed a ‘mussel zone of decline’. Mussels were exposed to the riverine sediments and to 3 control sediments for 28 d; survival, shell length, and biomass were then assessed. Sediment treatment (i.e., river location) had a significant effect on mussel survival (p < 0.01) and biomass (p = 0.02), but did not affect length (p = 0.37), and sediments from 2 of the tributaries were the most toxic. Inorganic and organic analyses of sediments indicated the presence of metals and polycyclic aromatic hydrocarbons at all sites. Manganese was negatively correlated with mussel survival and biomass, as was ammonia with survival, and total organic carbon with biomass. Current land uses in the watershed indicate that fossil fuel mining and agriculture may be associated with elevated manganese and ammonia, respectively. We found that sediments collected with sediment traps over relatively short deployment durations can help elucidate recent contaminant influx and its potential for inducing toxicity in benthic organisms.

Understanding the influence of multiple pollutant stressors on the decline of freshwater mussels in a biodiversity hotspot

“…For example, the Total PAH at Carterton was 4600 ng/g in bed sediment, but 54,000 ng/g in particulate sediment. This increase was reflected by the dominance of pyrogenic PAHs in the particulate sediment (Archambault et al, 2017).…”

“…Each sample consisted of 3 to 5 scoops, totaling approximately 200 mL, from the surface layer (top 5 cm) of depositional areas at each site. We also collected a time-integrated particulate sediment sample from the water column at each site (August 2013-February 2014), using sediment traps designed with an optimal aspect ratio for collecting sediments in lotic conditions (Hargrave and Burns, 1979), constructed and deployed as described by Archambault et al (2017). The sediment traps deployed at the Wallen Bend site were lost in a high flow event.…”

“…These declines have been attributed to numerous factors associated with pollution, water quality degradation, and habitat destruction and alteration (Strayer et al, 2004;Cope et al, 2008;Downing et al, 2010), including the rapid expansion of energy development and other extractive landuses (Patnode et al, 2015). Indeed, several recent laboratory studies have demonstrated that early life stages of mussels have a high sensitivity to some chemicals related to coal mining and natural gas extraction sites (Wang et al, 2007;Wang et al, 2011;Wang et al, 2013;Archambault et al, 2017). In field-based studies, inferring specific causes of mussel declines is often difficult because of potential confounding factors and the unique life history of mussels, which makes them especially susceptible to environmental stressors at several distinct life stages; nonetheless, chronic, low-level stressors are presumed as important influences (Strayer et al, 2004;Cope et al, 2008;Rogers et al, 2018).…”

“…Despite the global biological significance of the Clinch River as a biodiversity hotspot, mussel populations are declining in some segments, both in species richness and abundance, such that an 88-km reach of the river has been characterized as a mussel "zone of decline" (ZOD; Fig. 1; Jones et al, 2014;Archambault et al, 2017;Rogers et al, 2018). In this river reach from the confluence of the Clinch River with Dumps Creek near the town of Carbo, Virginia (river km 431) to Clinchport, Virginia (river km 343), mussel densities have decreased more than 70% from 1979 to 2004 (Jones et al, 2014).…”

Distribution, Period of Gravidity, and Host Identification for the Narrow Pigtoe Mussel

“…Researchers have attributed these problems to current and past land use practices, particularly row crop agriculture, timber harvest, and urban development, which have caused widespread alteration of terrestrial habitats (NWFWMD 1997). A recent study documented negative effects of freshly deposited sediments carrying excess manganese, ammonia, and organic carbon on the survival and biomass of freshwater mussels (Archambault et al 2017). Flashy tributaries carrying and depositing pulses of contaminated sediments from agrarian areas may be harming mainstem mussel populations downstream, especially in the Escambia River basin.…”