Toxicity of elevated partial pressures of carbon dioxide to invasive New Zealand mudsnails

Temperature-Related Responses of an Invasive Mussel and 2 Unionid Mussels to Elevated Carbon Dioxide

Zebra mussels (Dreissena polymorpha) have exacerbated the decline of native freshwater mussels (order Unionida) in North America since their arrival in the 1980s. Options for controlling invasive mussels, particularly in unionid mussel habitats, are limited. Previously, carbon dioxide (CO2 ) showed selective toxicity for zebra mussels, relative to unionids, when applied in cool water (12 °C). We first determined 96-h lethal concentrations of CO2 at 5 and 20 °C to zebra mussels and responses of juvenile plain pocketbook (Lampsilis cardium). Next, we compared the time to lethality for zebra mussels at 5, 12, and 20 °C during exposure to partial pressure of CO2 (PCO2 ) values of 110 to 120 atm (1 atm = 101.325 kPa) and responses of juvenile plain pocketbook and fragile papershell (Leptodea fragilis). We found efficacious CO2 treatment regimens at each temperature that were minimally lethal to unionids. At 5 °C, plain pocketbook survived 96-h exposure to the highest PCO2 treatment (139 atm). At 20 °C, the 96-h lethal concentration to 10% of animals (LC10) for plain pocketbook (173 atm PCO2 , 95% CI 147-198 atm) was higher than the LC99 for zebra mussels (118 atm PCO2 , 95% CI 109-127 atm). Lethal time to 99% mortality (LT99) of zebra mussels in 110 to 120 atm PCO2 ranged from 100 h at 20 °C to 300 h at 5 °C. Mean survival of both plain pocketbook and fragile papershell juveniles exceeded 85% in LT99 CO2 treatments at all temperatures. Short-term infusion of 100 to 200 atm PCO2 at a range of water temperatures could reduce biofouling by zebra mussels with limited adverse effects on unionid mussels. Environ Toxicol Chem 2020;39:1546-1557. Published 2020. This article is a U.S. Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Toxicity of Aqueous Alkaline Solutions to New Zealand Mudsnails, Asian Clams, and Quagga Mussels

We modeled the toxicity response of three important aquatic nuisance species to alkaline solutions of pH 12 to explore the potential use of chemical treatments for decontaminating infested water distribution systems, tanks, and other facilities in confined freshwater environments. Groups of quagga mussels Dreissena bugensis, New Zealand mudsnails Potamopyrgus antipodarum, and Asian clams Corbicula fluminea were tested in temperatures from 19 to 22°C in aqueous solutions adjusted to pH 12 with NaOH. The predicted 99% lethal exposure time (LT99) for adult-sized quagga mussels and New Zealand mudsnails respectively was 31.3 and 35.1 h. Longer exposures were needed to kill adult-sized Asian clams (LT99 = 208.9 h). Because of the worldwide use of NaOH as an alkaline reagent in a variety of industrial and pesticide applications, and its ease of neutralization with CO2, elevating the pH of freshwater solutions with NaOH may be a practicable management tool to remove nuisance species in biofouled canals, pipes, hatchery tanks, and other confined structures.

Effects of carbon dioxide on juveniles of the freshwater mussel (Lampsilis siliquoidea [Unionidae])

Carbon dioxide (CO₂ ) has shown promise as a tool to control movements of invasive Asian carp, but its effects on native freshwater biota have not been well studied. The authors evaluated lethal and sublethal responses of juvenile fatmucket (Lampsilis siliquoidea) mussels to CO₂ at levels (43-269 mg/L, mean concentration) that bracket concentrations effective for deterring carp movement. The 28-d lethal concentration to 50% of the mussels was 87.0 mg/L (95% confidence interval [CI] 78.4-95.9) and at 16-d postexposure, 76.0 mg/L (95% CI 62.9-90.3). A proportional hazards regression model predicted that juveniles could not survive CO₂ concentrations >160 mg/L for more than 2 wk or >100 mg/L CO₂ for more than 30 d. Mean shell growth was significantly lower for mussels that survived CO₂ treatments. Growth during the postexposure period did not differ among treatments, indicating recovery of the mussels. Also, CO₂ caused shell pitting and erosion. Behavioral effects of CO₂ included movement of mussels to the substrate surface and narcotization at the highest concentrations. Mussels in the 110 mg/L mean CO₂ treatment had the most movements in the first 3 d of exposure. If CO₂ is infused continuously as a fish deterrent, concentrations <76 mg/L are recommended to prevent juvenile mussel mortality and shell damage. Mussels may survive and recover from brief exposure to higher concentrations. Environ Toxicol Chem 2017;36:671-681. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.