Toxicokinetics of Ag in the terrestrial isopod Porcellionides pruinosus exposed to Ag NPs and AgNO3 via soil and food
Silver nanoparticles (Ag NPs) have been used in numerous consumer products and may enter the soil through the land application of biosolids. However, little is known about the relationship between Ag NP exposure and their bioavailability for soil organisms. This study aims at comparing the uptake and elimination kinetics of Ag upon exposures to different Ag forms (NPs and ionic Ag (as AgNO3)) in the isopod Porcellionides pruinosus. Isopods were exposed to contaminated Lufa 2.2 soil or alder leaves as food. Uptake and elimination rate constants for soil exposure did not significantly differ between Ag NPs and ionic Ag at 30 and 60 mg Ag/kg. For dietary exposure, the uptake rate constant was up to 5 times higher for Ag NPs than for AgNO3, but this was related to feeding activity and exposure concentrations, while no difference in the elimination rate constants was found. When comparing both routes, dietary exposure resulted in lower Ag uptake rate constants but elimination rate constants did not differ. A fast Ag uptake was observed from both routes and most of the Ag taken up seemed not to be eliminated. Synchrotron X-ray fluorescence showed Ag in the S-cells of the hepatopancreas, thus supporting the observations from the kinetic experiment (i.e. low elimination). In addition, our results show that isopods have an extremely high Ag accumulation capacity, suggesting the presence of an efficient Ag storage compartment.
KeywordsAg nanoparticles Bioaccumulation Exposure route Isopods Synchrotron
This work was supported by a Ph.D. Grant to P.S. Tourinho by the Portuguese Science and Technology Foundation (SFRH/BD/80097/2011) and conducted in the context of NanoFATE, Collaborative Project CP-FP 247739 (2010–2014) under the 7th Framework Programme of the European Commission (FP7-NMP-ENV-2009, Theme 4), coordinated by C. Svendsen and D. Spurgeon of NERC—Centre for Ecology and Hydrology, UK-Wallingford; www.nanofate.eu.
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Conflict of interest
The authors declare that they have no conflict of interest.
- Diez-Ortiz M, Lahive E, Kille P, Powell K, Morgan AJ, Jurkschat K, Van Gestel CAM, Mosselmans JFW, Svendsen C, Spurgeon DJ (2015) Uptake routes and toxicokinetics of silver nanoparticles and silver ions in the earthworm Lumbricus rubellus. Environ Toxicol Chem. doi: 10.1002/etc.3036
- Motulsky HJ, Ransnas LA (1987) Fitting curves to data using nonlinear regression: a practical and nonmathematical review. FASEB J 1:365–374Google Scholar
- Pipan-Tkalec Ž, Drobne D, Vogel-Mikuš K, Pongrac P, Regvar M, Štrus J, Pelicon P, Vavpetič P, Grlj N, Remškar M (2011) Micro-PIXE study of Ag in digestive glands of a nano-Ag fed arthropod (Porcellio scaber, Isopoda, Crustacea). Nucl Instrum Methods Phys Res Sect B 269:2286–2291CrossRefGoogle Scholar
- Van Gestel CAM, Straalen NM (1994) Ecotoxicological test systems for terrestrial invertebrates. In: Donker MH, Eijsackers H, Heimbach F (eds) Ecotoxicology of soil organisms. CRC Lewis Publishers, Boca Raton, pp 205–228Google Scholar