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Silver nanoparticles (AgNPs) are the dominating nanomaterial in consumer products due to their well-known antibacterial and antifungal properties. To enhance their properties, different surface coatings may be used, which affect physico-chemical properties of AgNPs. Due to their wide application, there has been concern about possible environmental and health consequences. Since plants play a significant role in accumulation and biodistribution of many environmentally released substances, they are also very likely to be influenced by AgNPs. In this study we investigated the toxicity of AgNO 3 and three types of laboratory-synthesized AgNPs with different surface coatings [citrate, polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB)] on Allium cepa roots. Ionic form of Ag was confirmed to be more toxic than any of the AgNPs applied. All tested AgNPs caused oxidative stress and exhibited toxicity only when applied in higher concentrations. The highest toxicity was recorded for AgNPs-CTAB, which resulted with increased Ag uptake in the roots, consequently leading to strong reduction of the root growth and oxidative damage. The weakest impact was found for AgNPs-citrate, much bigger, negatively charged NPs, which also aggregated to larger particles. Therefore, we can conclude that the toxicity of AgNPs is directly correlated with their size, overall surface charge and/or surface coating., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Acid mine drainage (AMD) is a by-product of the mining industry that has a detrimental effect on aquatic plant and animal life due to high load of heavy metals and sulfates. In the present study, the toxic and genotoxic potential of AMD prior to and following combination of neutralization/electrocoagulation processes was evaluated using several bioassays and selected parameters. Regardless of pH correction of AMD prior to Daphnia bioassay, high acute toxicity was observed in Daphnia magna. The mine leachate also induced strong phyto-, cyto- and genotoxicity to Allium cepa roots. Short term exposure to AMD inhibited duckweed growth and chlorophyll a content and simultaneously promoted lipid peroxidation and DNA damage despite duckweed capability to upregulate antioxidative defense mechanisms. The results show that observed (geno)toxicity could be related to oxidative stress most probably induced by toxic metal action. However, influence of low pH as a contributing factor in the phytotoxicity of AMD cannot be excluded. The application of combined treatment eliminated genotoxicity and was highly efficient in reducing toxicity of AMD. Thus, the method seems to be suitable for treatment of AMD waters enabling their safe discharge to an aquatic environment., (© 2013 Elsevier B.V. All rights reserved.)

The genotoxic and toxic potential of polluted surface water exposed to a fertilizer factory effluent was evaluated using assays with fish (Cyprinus carpio) and plant (Lemna minor) model organisms. Beside classical physicochemical parameters, the contents of fluorides, some heavy metals and polycyclic aromatic hydrocarbons were analyzed as well. Surface water caused inhibition of plant growth and decrease of photosynthetic pigment content. Regarding DNA damage and oxidative stress parameters, both fish and plants showed similar response to the surface water. In confirmation to biochemical markers, histopathological analysis of gill and liver tissues revealed a higher incidence of lesions in fish exposed to polluted surface water. Generally, results obtained by biological monitoring were mostly in agreement with chemical analysis of the surface water, although several discrepancies were observed which might be due to difference in sensitivity of model organisms or in experimental conditions (laboratory and field exposure). The results imply that conventional chemical analysis should be extended to genotoxicity/toxicity assays as measured biological effects and the potential health hazard cannot be predicted based on the physicochemical characteristics of water samples alone., (Copyright © 2013 Elsevier Inc. All rights reserved.)

In this investigation growth parameters and certain endpoints (pigment content, peroxidase activity, lipid peroxidation and alkaline comet assay) were used to detect the toxic and genotoxic effects of surface water samples on duckweed plants. The surface waters of different origin and pollutant burdens were collected monthly over a 3-month monitoring period at three sampling sites along the river Sava and its confluents (Croatia). Physicochemical characterization of the water samples included measurements of conductivity, chemical and biological oxygen demand, levels of total suspended solids, nitrate, nitrite, ammonium, Kjeldahl nitrogen and orthophosphate. Surface water samples collected from three stations caused reduction of duckweed growth rates, chlorophylls and carotenoid contents and peroxidase activity. In contrast, damage to membrane lipids (estimated by malondialdehyde content) and especially to DNA (estimated by tail extent moment) markedly increased in duckweed exposed to industrial wastewater samples. The results from the study indicate the ability of selected biomarkers to predict the phyto- and genotoxic effects of complex water mixtures on living organisms as well as the relevance of duckweed as a sensitive indicator of water quality., (Copyright © 2010 Elsevier Inc. All rights reserved.)