title: Aqueous Hg(2+) associates with TiO2 nanoparticles according to particle size, changes particle agglomeration, and becomes less bioavailable to zebrafish.
abstract: Engineered nanoparticles (NPs) have unique physicochemistry and potential to interact with other substances in the aqueous phase. Here, gene [metallothionein 2 (mt2)] expression changes in larval zebrafish were used to evaluate the association between aqueous Hg(2+) and TiO2 (NPs and bulk particle size control) to investigate the relationship between changes in Hg(2+) behavior and TiO2 size. During 24h exposures, TiO2 agglomerates increased in size and in the presence of 25μg Hg(2+)/L, greater increases in size were observed. The concentration of Hg(2+) in suspension also decreased in the presence of TiO2-NPs. Mercury increased expression of mt2 in larval zebrafish, but this response was lessened when zebrafish were exposed to Hg(2+) in the presence of TiO2-NPs, and which suggests that TiO2-NPs alter the bioavailability of Hg(2+) to zebrafish larvae. This ameliorative effect of TiO2 was also likely due to surface binding of Hg(2+) because a greater decrease in mt2 expression was observed in the presence of 1mg/L TiO2-NPs than 1mg/L TiO2-bulk. In conclusion, the results show that Hg(2+) will associate with TiO2-NPs, TiO2-NPs that have associated Hg(2+) will settle out of the aqueous phase more rapidly, and agglomerates will deliver associated Hg(2+) to sediment surfaces.
authors.affiliation: Recep Tayyip Erdoğan University, Faculty of Fisheries, 53100 Rize, Turkey; Karadeniz Technical University, Department of Fisheries Technology Engineering, Faculty of Marine Science, 61530 Surmene, Trabzon, Turkey; School of Biological Sciences, Plymouth University, Plymouth PL4 8AA, UK.
authors.forename: Halis
authors.initials: H
authors.lastname: Boran
authors.affiliation: School of Biological Sciences, Plymouth University, Plymouth PL4 8AA, UK. Electronic address: david.boyle@plymouth.ac.uk.
authors.forename: David
authors.initials: D
authors.lastname: Boyle
authors.affiliation: Karadeniz Technical University, Department of Fisheries Technology Engineering, Faculty of Marine Science, 61530 Surmene, Trabzon, Turkey.
authors.forename: Ilhan
authors.initials: I
authors.lastname: Altinok
authors.affiliation: School of Life Sciences, Heriot-Watt University, Edinburgh, Lothian EH14 4AS, UK.
authors.forename: Danae
authors.initials: D
authors.lastname: Patsiou
authors.affiliation: School of Biological Sciences, Plymouth University, Plymouth PL4 8AA, UK; School of Life Sciences, Heriot-Watt University, Edinburgh, Lothian EH14 4AS, UK; Department of Forestry, Wildlife and Fisheries, Center for Environmental Biotechnology, The University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Theodore B
authors.initials: TB
authors.lastname: Henry
mesh_terms: D000818:Animals; D001682:Biological Availability; D005786:Gene Expression Regulation / Q000187:drug effects*; D008628:Mercury / Q000737:chemistry* / Q000633:toxicity; D008668:Metallothionein / Q000235:genetics; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D014025:Titanium / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000633:toxicity; D015027:Zebrafish
chemical_list: D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D008668:Metallothionein; D014025:Titanium; D008628:Mercury
keywords: Mercury; Metallothionein; Sorption; Titanium dioxide nanoparticles; Zebrafish