The Relative Toxicity of Road Salt Alternatives to Freshwater Mussels; Examining the Potential Risk of Eco-Friendly De-icing Products to Sensitive Aquatic Species

Abstract

The negative impact of road salt on freshwater ecosystems has led to an interest in “eco-friendly” de-icing products. Biota, including freshwater mussels that have heightened salt sensitivity, would be expected to benefit from a transition to alternative de-icing products. However, it was unknown whether the alternatives themselves pose a risk. The toxicity of three road salt alternatives including a salt brine, a beet juice, and a brine–beet juice product were examined. Lampsilis fasciola glochidia (larvae) were exposed to dilutions (0–2%) of de-icing products. On a per volume basis, beet juice products were significantly more toxic than brine with 48 h EC50s (95% confidence intervals) as follows: brine, 0.42% (0.35–0.50%); beet juice, 0.020% (0.018–0.022%); and brine–beet juice, 0.034% (0.028–0.039%). Unlike brine, beet juice toxicity did not correspond with the concentration of chloride in the exposure. While elevated trace metals (Cu, Fe, Zn) and reduced water quality occurred in the 1% and 2% beet juice exposures, toxicity occurred at much lower dilutions (≤0.05%). The toxicity of beet juice products aligned with glochidia potassium EC50s. Based on toxicity and application rates, beet juice de-icing products pose more of a hazard to early life stage mussels than traditional products and could contribute substantial potassium to receiving environments.

Alterations to unionid transformation during agricultural and urban contaminants of emerging concern exposures

“…After release from the maternal brood, glochidia experienced both a brief direct exposure to contaminants during host fish infestation and potential indirect exposure while encysted on host fish. Few studies address the importance of host fish contaminant exposure relative to glochidia exposure in determining transformation rates, but available evidence indicates glochidia exposure as a more important factor (Jacobson et al, 1997 , Hazelton et al, 2012 , Beggel and Geist, 2015 , Gillis et al, 2021 ). Maternal unionids, glochidia, and host fish were from the same exposure duration treatments, and thus we cannot determine if juvenile transformation was influenced by host fish exposure, direct contact of glochidia with CECs during infestation, or previously discussed glochidia exposure in brood.…”

Combined effects of copper, nickel, and zinc on growth of a freshwater mussel (Villosa iris) in an environmentally relevant context

“…Working with the freshwater mussel Anodonta imbecilis, Keller and Zam (1991) found that two-metal mixtures including Cu, Ni, and/or Zn were generally more toxic, as determined by 24-and 48 h median lethal concentrations (LC50s), than single-metal exposures; but two-metal mixtures including Cd tended to be less toxic by that measure. Gillis et al (2021) observed greater sensitivity of freshwater mussel Lampsilis fasciola glochidia (larvae) to chloride when a complex mixture of metals was included in the exposure. Both Appalachian coal-mine spoil leachates and mining-influenced sections of the Clinch and Powell Rivers are known to be elevated in multiple constituents, including Al, As, Cd, Mn, and/or Se as well as the three metals studied here (Zipper et al, 2016;Clark et al, 2018;VDEQ/TDEC, 2018).…”

Evaluation of Chronic Effects of Potassium Chloride and Nickel on Survival, Growth, and Reproduction of a Unionid Mussel (Lampsilis siliquoidea)

“…Noticeably, Rogers et al (2023) recently found a significantly greater abundance of tissue abnormalities in digestive glands and kidneys of subadult rainbow mussel ( Villosa iris ) at exposure concentrations of as low as 4.2 mg K/L relative to the control after a 61‐day KCl exposure in a pond water (hardness ~210 mg/L as CaCO 3 ), indicating that effect concentrations on mussel organ tissues could be below the chronic effect concentrations based on mussel survival and growth. Glochidia and juvenile mussels are also highly sensitive to acute KCl exposures (Gillis et al, 2021; Salerno et al, 2019; Wang, Ivey, Dorman, et al, 2018). Potassium is often elevated in industrial and municipal wastewater treatment plant effluents and in discharges from oil and gas production operations (Kunz et al, 2021; Liden et al, 2018).…”

“…Potassium is often elevated in industrial and municipal wastewater treatment plant effluents and in discharges from oil and gas production operations (Kunz et al, 2021; Liden et al, 2018). The importance of developing water quality guidelines for protecting mussels and other sensitive organisms has been well addressed in several publications (Gillis et al, 2021; Kunz et al, 2021; Wang et al, 2017; Wang, Ivey, Dorman, et al, 2018).…”