Effects of silver nanoparticles (NM‐300K) onLumbricus rubellusearthworms and particle characterization in relevant test matrices including soil

Abstract

The impact of silver nanoparticles (AgNP; at 0 mg Ag/kg, 1.5 mg Ag/kg, 15.4 mg Ag/kg, and 154 mg Ag/kg soil) and silver nitrate (AgNO3 ; 15.4 mg Ag/kg soil) on earthworms, Lumbricus rubellus, was assessed. A 4-wk exposure to the highest AgNP treatment reduced growth and reproduction compared with the control. Silver nitrate (AgNO3 ) exposure also impaired reproduction, but not as much as the highest AgNP treatment. Long-term exposure to the highest AgNP treatment caused complete juvenile mortality. All AgNP treatments induced tissue pathology. Population modeling demonstrated reduced population growth rates for the AgNP and AgNO3 treatments, and no population growth at the highest AgNP treatment because of juvenile mortality. Analysis of AgNP treated soil samples revealed that single AgNP and AgNP clusters were present in the soil, and that the total Ag in soil porewater remained high throughout the long-term experiment. In addition, immune cells (coelomocytes) of earthworms showed sensitivity to both AgNP and AgNO3 in vitro. Overall, the present study indicates that AgNP exposure may affect earthworm populations and that the exposure may be prolonged because of the release of a dissolved Ag fraction to soil porewater.

Collembola Reproduction Decreases with Aging of Silver Nanoparticles in a Sewage Sludge-Treated Soil

“…Other authors have also seen a rise in toxicity of AgNP to soil invertebrates with time when aged in soil. van der Ploeg et al (2014) detected lower juvenile hatchability and survival of Lumbricus rubellus for NM-300K than AgNO 3 at 15 mg Ag kg −1 in a long-term study. They suspect that NM-300K have longer lasting toxic effects, because of Ag ion dissolution, than AgNO 3 which on the short-term is more toxic (van der Ploeg et al, 2014).…”

“…van der Ploeg et al (2014) detected lower juvenile hatchability and survival of Lumbricus rubellus for NM-300K than AgNO 3 at 15 mg Ag kg −1 in a long-term study. They suspect that NM-300K have longer lasting toxic effects, because of Ag ion dissolution, than AgNO 3 which on the short-term is more toxic (van der Ploeg et al, 2014). For Eisenia fetida toxicity of uncoated AgNP also increased with aging time and the authors suspect the same mechanism behind this (Diez-Ortiz et al, 2015).…”

“…The focus in ecotoxicological testing of AgNP in soil has, thus far, been more on microorganisms (Schlich et al, 2013b;Engelke et al, 2014;McKee and Filser, 2016), earthworms (Heckmann et al, 2011;Shoults-Wilson et al, 2011a;Schlich et al, 2013a;van der Ploeg et al, 2014;Novo et al, 2015), enchytraeids (Gomes et al, 2013(Gomes et al, , 2015Ribeiro et al, 2015;Bicho et al, 2016) and nematodes (Roh et al, 2009;Meyer et al, 2010). Collembola have received less attention.…”

In vitro assays for hazard identification of nanoparticles

“…Elemental information about the sample can also be obtained by atomic spectrometry methods such as inductively coupled plasma optical emission spectrometry (ICP-OES) (Elzey et al 2012) and ICP mass spectrometry (ICP-MS) (Krystek 2012, Krystek et al 2013), especially in single particle mode (sp ICP-MS) (Laborda et al 2014, Pace et al 2011, Peters et al 2014a. From these studies it becomes clear that he smallest particle sizes that now can be determined are around 20 nm for silver and gold nanoparticles.…”

“…Aqueous media containing nanoparticles only need limited sample preparation; samples may be sonicated or tip-sonicated to suspend materials and proteins such as bovine serum albumin (BSA), or detergents such as sodium dodecylsulphate (SDS) may be added to stabilize nanoparticle suspensions (Jensen et al 2011). For other matrices, matrix removal or nanoparticle isolation from the matrix can be achieved by physical processes such as centrifugation, fi ltration, column techniques or cloud point extraction, or by chemical or enzymatic destruction of the matrix (Loeschner et al 2014, Peters et al 2014a.…”