To Örebro University

Metal contamination of aquatic environments remains a major concern and has received significant attention in recent years. The present study aimed to evaluate the effects of metal mixtures of varying concentrations over time in a lake receiving runoff water from a decommissioned mine. By subjecting several organisms to this water, we aimed to identify the most susceptible species, thus enabling a comprehensive evaluation of the risk posed by different toxins to the biotic environment.

We have evaluated the effects of mixed metal exposure on survival and stress gene expression in selected invertebrate and vertebrate model species. Our observations revealed differences in sensitivity among the invertebrate models Caenorhabditis elegans, Daphnia magna, Ceriodaphnia dubia, and Heterocypris incongruens, as well as in the vertebrate model Zebrafish (Danio rerio) and two cell lines; a zebrafish liver cell line (ZFL) and a human hepatocellular carcinoma cell line (HepG2). While the sensitivity shows great variation among the tested species, the expression of metallothionein was consistent with the levels of metals found in the mixed exposure media. Despite differences in acute toxicity, the universal induction of mt1/A and mt2/B genes make them an important biomarker for assessing the environmental risk of metals.

Ionic liquids (ILs), are organic salts and have been referred to as greener solvents, oftentimes also termed designer solvents. They are separated into classes namely room temperature ILs (RTILs), task-specific ILs (TSILs), polyionic liquids (PLILs), and supported ILs, among others. ILs are used as solvents because of their low vapour pressure at room temperature as well as thermal stability. Because of their widespread applications in diverse fields, they may contribute to contaminating the land and aquatic environment as the majority of them are chemically stable. Although many researchers have labelled the ILs as green in nature there is an enormous possibility for their release into the environment in many ways. Although the variety of ILs and their synthesis are continuously increasing however scant attention has been paid to their remediation strategies; toxicological information generated in the last decade does provide a report on the impact of ILs on lower organisms and plants. Therefore, to enhance the toxicological understanding of ILs, it is a prerequisite to assemble their recent toxicological information on various living forms. This knowledge certainly will offer new clues about their interaction at the physiological and molecular scale of an organism and thus contribute to the fulfilling gap in our toxicological understanding. Hence, this review article highlights the recent toxicological impact of newly synthesized ILs on microbes, vertebrates, invertebrates, animal cells, and plants where the summarised toxicological facts have expounded the effect of ILs in dose dependent manner associated with their structure. Similarly, the impact of various ILs at the cellular level of the organism is discussed. This review also sums up the current development of computational modelling for evaluation of toxicity testing that may minimize the animal experimental dependency thus providing a future guideline in designing the greener ILs.