Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Toxicity of various road-deicing salts to Asian clams (Corbicula fluminea).

Abstract

Humans are altering environments by destroying habitats, introducing species, and releasing pollution. One emergent pollutant is the salinization of freshwater habitats from road-deicing salts. Government agencies have set thresholds to protect freshwater ecosystems, yet these values are exceeded in many systems. The present study investigated the tolerance of Asian clams (Corbicula fluminea), a common invasive bivalve, to the common road salt (sodium chloride [NaCl]) and 2 alternatives (magnesium chloride [MgCl2] and calcium chloride [CaCl2]). Experiments conducted at 4 and 8 d revealed that Asian clams are very salt tolerant. The median lethal concentration after 4 d of exposure (LC504-d) estimate was 2162 mg Cl-/L for MgCl2, 3554 mg Cl-/L for CaCl2, and more than 22 581 mg Cl-/L for NaCl, which were all significantly different from each other (p≤0.05). The LC508-d values were significantly different (p≤0.05) from each other and from the LC504-d values, and were estimated to be 1769 mg Cl-/L for MgCl2, 2235 Cl-/L for CaCl2, and 10 069 mg Cl-/L for NaCl. Mortality was determined using 2 methods: either no response after exposure or no response after being in freshwater following exposure. For the majority of the LC50s, these methods were not significantly different (p>0.05). The high salt tolerance of Asian clams is a concern because of their transportation in ballast water between aquatic ecosystems. Furthermore, salt-tolerant organisms may outcompete sensitive organisms in salinized ecosystems, which may alter ecosystem services.