Copper Concentrations in the Upper Columbia River as a Limiting Factor in White Sturgeon Recruitment and Recovery

Abstract

Currently there is little natural recruitment of white sturgeon (Acipenser transmontanus) in the Upper Columbia River located in British Columbia, Canada and Washington, USA. This review of life history, physiology, and behavior of white sturgeon, along with data from recent toxicological studies, suggest that trace metals, especially Cu, affect survival and behavior of early life stage fish. Sturgeon free embryos, first feeding embryos, and mixed feeding embryos utilize interstitial spaces between gravel. Although concentrations of Cu in the water column of the Upper Columbia River are typically less than US water quality criteria defined to protect aquatic life, samples at the sediment-water interface were as large as 24 µg/L and exceed the criteria. Toxicological studies reviewed here demonstrate mortality, loss of equilibrium, and immobility at Cu concentrations of 1.5 to <16 µg/L and reduced swimming activity was documented at 0.88 to 7 μg/L. Contaminated invertebrates and slag particles provide other routes of exposure. These additional routes of exposure can cause indirect effects from starvation due to potential lack of prey items and ingestion of contaminated prey or slag particles. The lack of food in stomachs during these critical early life stages may coincide with a threshold "point of no return" at which sturgeon will be unable to survive even if food becomes available following that early time frame. These findings become especially important as work progresses to enhance white sturgeon recruitment in the Upper Columbia River. To date, decisions against including trace metals as a factor in sturgeon recovery have focused on surface-water concentrations and measurements of lethality (LC50) to establish threshold concentrations for sturgeon sensitivity. However, information provided here suggests that measurements from the sediment-water interface and effect concentrations (EC50) be considered with white sturgeon life history characteristics. These data support minimizing Cu exposure risk to enhance a successful white sturgeon recovery effort. Integr Environ Assess Manag 2020;16:378-391. Published 2020. This article is a US Government work and is in the public domain inthe USA.

Using Multiple Metal Mixture Models to Predict Toxicity of Riverine Sediment Porewater to the Benthic Life Stage of Juvenile White Sturgeon (Acipenser transmontanus)

“…However, all metal mixture models, with some exceptions for Pb, predict that Cu is the major contributor (>80%) to toxicity at >20% adverse response of juvenile white sturgeon exposed to porewater in Upper Columbia River Basin shallow sediment. This result, as well as comparisons of free Cu ion activities in porewater with EC20 activities determined from bioassay studies (see the section, In situ porewater: Compositions) and previous studies of metal fluxes across the sediment-water interface and sturgeon life cycles in the Upper Columbia River Basin, point to Cu as the element of toxicity to young sturgeon in the Upper Columbia River Basin (Balistrieri et al, 2018;Puglis et al, 2020).…”

“…Laboratory bioassay studies indicate that increasing concentrations of bioavailable dissolved metals result in effective mortality and biomass reduction of juvenile white sturgeon (Ingersoll et al, 2014; Wang et al, 2014). Early life stages of sturgeon are exposed to bioavailable dissolved metals, especially Cu, in near‐surface porewater during their vulnerable hiding stage, resulting in potential adverse impacts on their growth and survival (Balistrieri et al, 2018; Puglis et al, 2020).…”

“…Sturgeon spawn in freshwater habitats with gravel, cobbles, and boulders during peak river flow. Newly hatched sturgeon hide in these hard substrates and associated interstitial fine grain sediment for a few weeks, and this behavior can expose them to metal-enriched sediment and porewater at some locations in the Upper Columbia River Basin (Bennett et al, 2007;McAdam, 2011;Puglis et al, 2020).…”

“…Sturgeon spawn in freshwater habitats with gravel, cobbles, and boulders during peak river flow. Newly hatched sturgeon hide in these hard substrates and associated interstitial fine grain sediment for a few weeks, and this behavior can expose them to metal‐enriched sediment and porewater at some locations in the Upper Columbia River Basin (Bennett et al, 2007; McAdam, 2011; Puglis et al, 2020). Because metal contamination in the Upper Columbia River Basin poses potential risks to humans, terrestrial and aquatic life, and the environment, the USEPA is currently conducting a Remedial Investigation and Feasibility Study (RI/FS) and Baseline Ecological Risk Assessment (BERA) from the US/Canadian border to the Grand Coulee Dam (WA, USA; USEPA, 2023).…”

Refining our understanding of metal bioavailability in sediments using information from porewater: Application of a multimetal biotic ligand model as an extension of the equilibrium partitioning sediment benchmarks

“…The equilibrium partitioning (EqP) approach presented by the US Environmental Protection Agency (USEPA) in 2005 provides a framework for assessing whether metal concentrations in sediment and porewater (i.e., interstitial water) are expected to be associated with toxicological effects on benthic organisms (USEPA, 2005). There are many examples of the application of the EqP approach to sediment (DeForest et al, 2021), but fewer exist for porewater (Puglis et al, 2020; Santore & Ryan, 2015); to the best of our knowledge, there are no published examples wherein both approaches were applied and the accuracy of each approach was compared with that of the other. In this analysis, EqP evaluations of porewater and sediment chemistry are used in concert to understand the contributions of metals to toxicity observed in bioassays of field‐collected sediments.…”