abstract
The study aimed to evaluate the efficiency of dithiocarbamate functionalized silica coated magnetite nanoparticles (NPs) for Hg decontamination of saltwater either contaminated with Hg alone or with As and Cd. For this, the residual levels of Hg in seawater were assessed and Hg-contaminated or Hg+ As+ Cd-contaminated seawater toxicity to aquatic biota, before and after the sorption process, was compared. The results showed that under highly competitive conditions (water salts, Cd and As), the removal of Hg from seawater, by using these magnetic NPs, for the lowest concentration (50 mu g/L) was superior to 98% and for the highest concentration (500 mu g/L) ranged between 61% to 67%. Despite the great affinity of the magnetic NPs for Hg, they were not effective at removing As and Cd from seawater. In relation to the ecotoxicity endpoints after remediation, the mixture with lower Hg concentration exhibited no toxicity to rotifer Brachionus plicatilis and bacteria Vibrio fischeri; however, the mixture with higher concentration revealed toxicity. In addition, the toxicity of bacteria V. fischeri, rotifer B. plicatilis and algae Phaeodactylum tricornutum, whose responses where inhibited during its exposure to the non-remediate sample was considerably reduced after treatment with NPs. Furthermore, microalgae P. tricornutum appears to be most sensitive species while Artemia franciscana showed no toxic effects to the tested solutions. Both chemical and ecotoxicological approaches revealed a high efficiency for the remediation of Hg-contaminated saltwater. (C) 2016 Elsevier B.V. All rights reserved.
keywords
MINNOWS PIMEPHALES-PROMELAS; DIETARY METHYLMERCURY; FATHEAD MINNOWS; MESOPOROUS SILICA; WASTE-WATER; INORGANIC MERCURY; METAL REMOVAL; HG2+ IONS; BEHAVIOR; INHIBITION
subject category
Environmental Sciences & Ecology
authors
Mohmood, I; Lopes, CB; Lopes, I; Tavares, DS; Soares, AMVM; Duarte, AC; Trindade, T; Ahmad, I; Pereira, E
our authors
Cláudia Batista Lopes
Assistant Researcher
Daniela Soraia dos Santos Tavares
PhD Student
Tito Trindade
Full professoracknowledgements
We would like to thank University of Aveiro, FCT/MEC for the financial support to CESAM, CICECO and CIIMAR (UID/AMB/50017/2013; UID/CTM/50011/2013; UID/Multi/04423/2013) through national funds and, where applicable, co-financed by the FEDER, within the PT2020 Partnership Agreement.; We also would like to thank the National Funds through the Portuguese Foundation for Science and Technology (FCT) through a FCT project (PTDC/MAR-BIO/3533/2012), and doctoral and postdoctoral grants to I. Mohmood (SFRH/BD/74410/2010) and to C.B. Lopes (SFRH/BPD/99453/2014).