Imidazolium based ionic liquids in soils: effects of the side chain length on wheat (Triticum aestivum) and cress (Lepidium sativum) as affected by different clays and organic matter

Abstract

This study provides data on the behaviour and toxicity of selected imidazolium based ionic liquids in the terrestrial environment with the aim to contribute to a prospective hazard assessment. Using the plant growth inhibition assay with wheat (Triticum aestivum) and cress (Lepidium sativum) we investigated the influence of two different clay minerals (kaolinite and smectite) in varying concentrations and clay mineral mixtures as well as the influence of organic matter in varying concentrations on the toxicity of three imidazolium based ionic liquids differing in the alkyl side chain length. The obtained results were compared to the German standard soil Lufa 2.2. Overall the influence of the 2:1 layer mineral smectite on toxicity was stronger than for the 1:1 layer mineral kaolinite resulting in lower toxicities when smectite was present. Comparable results were achieved in the tests with different clay mineral mixtures. The influence of the clay minerals was substance concentration dependent and the side chain effect could not consistently be confirmed for the different soil mixtures. The 1:1 clay mineral kaolinite caused in some cases an increase in toxicity. The obtained results for the influence of organic matter on the toxicity proved to be much more consistent than for the clay minerals: here an increase in organic matter concentration always resulted in a decrease of the toxicity. Differences in plant species sensitivity could be shown, but not in a consistent manner. A site specific hazard assessment of ionic liquids should therefore take into account organic matter content, quantity and especially quality of clay minerals.

Comparison of Phytotoxicity of Selected Phosphonium Ionic Liquid

“…The quoted literature shows that a likely toxic influence of a ionic liquid is determined by a number of factors, of which the primary role is played the cation type and the length of the substituent in the cation (as a rule, the longer alkyl chain, the higher toxicity). The anion type is not without significance, either; but the concentration of the substance used and the habitat conditions, including the presence of other xenobiotics, and the species features of the organism tested are also all-important [1,4,8,9,15,17,18,21,36,37]. The studies of the potential ecotoxicity of ionic liquids has not only a learning and ecological aspect, which eliminates the risk of failure in the process of issuing permits for industrial use and trade in these substances, but are also important for economic reasons, as they prevent any financial expenditures on the rectification of possible damage in the natural environment [29].…”

“…With reference to this problem, along with scientific reports on the synthesis, physical and chemical properties and the potential for practical utilization of ionic liquids, a large number of studies have come up, which are concerned with the examination of the potential toxicity of these substances. Studies described in available literature reveal varied influences of ionic liquids on microorganisms [1,2,[17][18][19][20][21][22], plankton [21,[23][24][25][26], invertebrates [27][28][29], vertebrates [27,30], algae [2,21,23,29,[31][32][33], fungi [19,34,35] or higher land plants [8,21,31,[36][37][38][39]. The quoted literature shows that a likely toxic influence of a ionic liquid is determined by a number of factors, of which the primary role is played the cation type and the length of the substituent in the cation (as a rule, the longer alkyl chain, the higher toxicity).…”

“…This element of research is inseparably connected with the occurrence of mineral and organic colloids in soil, whose presence is responsible for the magnitude of soil sorption. Soil sorption is decisive in retaining many chemical substances in soil colloids, including toxic substances, because eg humus, as a negatively charged colloid, is able to adsorb ionic liquid cations; also mineral colloids contribute to the level of the toxic influence of many adsorbed xenobiotics [31,36,38]. The potential phytotoxicity of ionic liquids not only depends on the quantity and quality of soil colloids, but it can also be determined by the amount of a ionic liquid in the substrate and the genetic features of species or varieties [8,15,21,37,39].…”

Recent trends in whole cell and isolated enzymes in enantioselective synthesis

“…They have been reported to possess antibacterial activity, cytoxicity and toxicity towards multicellular organisms, 162 and ecotoxicity in the case of aquatic organisms and terrestrial plants. 163,164 3.4. Novel application of fluorous solvents in product isolation following biocatalysis An interesting application of solvents for biocatalysis was developed in 2002 by Theil et al [165][166][167] Initially lipase-mediated kinetic resolution of a range of alcohols with fluorous esters was performed and repeated washing with the fluorous solvent removed the transformed ester in high enantiopurity with the untransformed alcohol remaining in the organic phase also in excellent enantiopurity.…”

Two-Stage Prediction of the Effects of Imidazolium and Pyridinium Ionic Liquid Mixtures on Luciferase

“…Although ILs will not cause air pollution because of their negligible vapor pressures, some of them still present a non-negligible solubility in water, thus leading to aquatic environmental risks [9]. Several studies have reported the biological effects of single ILs on the basis of different toxicological test systems such as enzymes (e.g., acetylcholinesterase), bacteria (e.g., Vibrio fischeri), algae (e.g., Selenastrum capricornutum), mammalian cells (e.g., MCF-7 cell), plants (e.g., wheat and cress), invertebrates (e.g., zebra mussel), and vertebrates (e.g., Danio rerio) [10][11][12][13][14][15][16].…”