Showing papers by "Peter Roslev published in 2015"
TL;DR: The study suggests that bioassays with luminescent A. fischeri, and fluorescent assays targeting hydrolytic enzyme activity are good candidates for monitoring microbial MTBE toxicity in contaminated water.
31 citations
TL;DR: In this paper, five different inorganic membranes were tested, namely, an α-alumina microfiltration membrane, an anatase titania ultrafiltration, a γ-aluminina nanofiltration membrane and an amorphous hybrid organo-silica membrane.
Abstract: Effluent from the secondary treatment of municipal wastewater was treated with membrane filtration to reduce its toxicity. Five different inorganic membranes were tested, namely, an α-alumina microfiltration membrane, an anatase titania ultrafiltration membrane, a γ-alumina nanofiltration membrane, an amorphous titania nanofiltration membrane, and an amorphous hybrid organo-silica membrane. The permeabilities and selectivities (color, UV254-absorbing components, conductivity and inorganic nitrogen compounds) of the membranes were determined, and the γ-alumina nanofiltration membrane was found to be the most promising membrane for the treatment of the effluent. The effluent flux was measured to be approximately 40 L m–2 h–1 for the γ-alumina nanofiltration membrane, and it removed nearly 75% of the UV254-absorbing components and 15% of the ions. It also removed 40% of the CuCl and 25% of the CuSO4 from the spiked effluent. The fouling resistance was less pronounced for the γ-alumina membrane compared with ...
13 citations
TL;DR: The results suggest that the fluorescence-based hydrolytic enzyme activity assay (FLEA assay) can be used as an index of D. magna stress and combined enzyme activity with fluorescence measurements may be applied as a simple and quantitative supplement for toxicity testing with D. Magna.
Abstract: Daphnia magna is a widely used model organism for aquatic toxicity testing. In the present study, the authors investigated the hydrolytic enzyme activity of D. magna after exposure to toxicant stress. In vivo enzyme activity was quantified using 15 fluorogenic enzyme probes based on 4-methylumbelliferyl or 7-amino-4-methylcoumarin. Probing D. magna enzyme activity was evaluated using short-term exposure (24–48 h) to the reference chemical K2Cr2O7 or the herbicide formulation Roundup®. Toxicant-induced changes in hydrolytic enzyme activity were compared with changes in mobility (International Organization for Standardization standard 6341). The results showed that hydrolytic enzyme activity was quantifiable as a combination of whole body fluorescence of D. magna and the fluorescence of the surrounding water. Exposure of D. magna to lethal and sublethal concentrations of Roundup resulted in loss of whole body enzyme activity and release of cell constituents, including enzymes and DNA. Roundup caused comparable inhibition of mobility and alkaline phosphatase activity with median effective concentration values at 20 °C of 8.7 mg active ingredient (a.i.)/L to 11.7 mg a.i./L. Inhibition of alkaline phosphatase activity by Roundup was lowest at 14 °C and greater at 20 °C and 26 °C. The results suggest that the fluorescence-based hydrolytic enzyme activity assay (FLEA assay) can be used as an index of D. magna stress. Combining enzyme activity with fluorescence measurements may be applied as a simple and quantitative supplement for toxicity testing with D. magna. Environ Toxicol Chem 2015;34:1841–1850. © 2015 SETAC
11 citations