Acute and chronic toxicity of imidazolium‐based ionic liquids on Daphnia magna

Abstract

Room-temperature ionic liquids (ILs) are considered to be green chemicals that may replace volatile organic solvents currently used by industry. However, IL effects on aquatic organisms and ecosystems are currently unknown. We studied the acute effects of imidazolium-based ILs on survival of the crustacean Daphnia magna and their chronic effects on number of first-brood neonates, total number of neonates, and average brood size. Lethal concentrations of imidazolium ILs with various anions (X-) ranged from a median lethal concentration (LC50) of 8.03 to 19.91 mg L(-1), whereas salts with a sodium cation (Na+ X-) were more than an order of magnitude higher (NaPF6 LC50, 9,344.81 mg L(-1); NaBF4 LC50, 4765.75 mg L(-1)). Thus, toxicity appeared to be related to the imidazolium cation and not to the various anions (e.g., Cl-, Br-, PF6-, and BF4-). The toxicity of imidazolium-based ILs is comparable to that of chemicals currently used in manufacturing and disinfection processes (e.g., ammonia and phenol), indicating that these green chemicals may be more harmful to aquatic organisms than current volatile organic solvents. We conducted 21-d chronic bioassays of individual D. magna exposed to nonlethal IL concentrations at constant food-resource levels. Daphnia magna produced significantly fewer total neonates, first-brood neonates, and average neonates when exposed to lower concentrations (0.3 mg L(-1)) of imidazolium-based ILs than in the presence of Na-based salts at higher concentrations (400 mg L(-1)). Such reductions in the reproductive output of Daphnia populations could cascade through natural freshwater ecosystems. The present study provides baseline information needed to assess the potential hazard that some ILs may pose should they be released into freshwater ecosystems.

Room-temperature ionic liquids meet bio-membranes: the state-of-the-art

“…Their introduction into industrial processes, together with their organic character, motivated the first studies of their interaction with biomolecules and bio-organisms (Petkovic et al 2011). As a result, several studies have highlighted their toxicity on living organisms (Pretti et al 2006;Bernot et al 2005;Ranke et al 2006Ranke et al , 2007aStolte et al 2007;Kulacki and Lamberti 2008). Toxicity is also a measure of the high affinity between RTILs and biosystems.…”

Ionic liquid-tolerant microorganisms and microbial communities for lignocellulose conversion to bioproducts

“…ILs have similar structures to detergents, pesticides and antibiotics which attack lipid structure, resulting in an increase in osmotic pressure and disruption of the membrane of microorganisms (Matsumoto et al 2004;Pernak et al 2001;Pernak et al 2003;Pham et al 2010). Moreover, one study suggested that some ILs are similar to cationic surfactants which induce polar narcosis due to their interfacial properties, causing membrane-bound protein disruption (Bernot et al 2005). The toxicity of certain ILs can also inhibit enzymatic activity of microorganisms due to accumulation in cell membranes (Matsumoto et al 2004;Pham et al 2010;Romero et al 2008).…”

Bioaccumulation of 1-butyl-3-methylimidazolium chloride ionic liquid in a simple marine trophic chain

“…However, the results obtained in this study should also be interpreted in terms of the relatively high ILs toxicity to marine organisms. EC50 of 1-butyl-3-methylimidazolium ionic liquid in the mussel Physa acuta was calculated to be 1.31 mM (Bernot et al 2005), whereas EC50 of bmimCl in various algae (Chlorella vulgaris, Oocystis submarina, Cyclotella meneghiniana, Skeletonema marinoi, Bacillaria paxillifer, Geitlerinema amphibium) was found to range from 0.003 to 1.02 mM (Latała et al 2009a, b). The calculated BCFs are therefore likely to be several times higher than the effective concentrations for typical primary producers and their consumers in the marine trophic chain.…”