NanoFASE - element

Nanomaterials are expected to appear in the environment through sewage sludge application onto agricultural fields or direct application of agrochemicals. Because of reduction conditions during wastewater treatment, resulting in the presence of a large proportion of sulfide, Ag ions or Ag NPs are likely to be transformed into Ag₂S, which then can be present in biosolids. NanoFASE performed an indoor mesocosm experiment to evaluate Ag uptake by diverse terrestrial organisms. Mealworm (Tenebrio molitor), wheat plants (Triticum aestivum L.), isopods (Porcellio scaber) and earthworms (Lumbricus rubellus) were exposed for 28 days in soil whose 10-cm top layer was spiked with Ag₂S NP or AgNO₃ at 10 mg Ag per kg⁻¹ soil; the 10-cm bottom layer was clean soil.

Study aim

The aim of this work was to determine the uptake of Ag₂S NP (simulating Ag ageing in wastewater treatment plants) in a range of terrestrial biota under a relevant environmental exposure scenario and thus to verify results and patterns obtained under uni-species tests.

Experimental approach

Overview

Compartment involved:

Soil

NP type/size:

Ag₂S NPS were provided by AppNAno

Species:
Plants (Triticum aestivum L.)
Mealworm (Tenebrio molitor)
Isopods (Porcellio scaber)
Earthworms (Lumbricus rubellus)

Assay:
Soil column

Results

In some of the species (e.g. mealworms), uptake of Ag₂S NP under mesocosm conditions was similar to that seen in the single species experiments.

Parameters

Emitted to

k1 = uptake rate constant (g_soil/g_animal/day);

k2 = elimination rate constant (day-1)

SF= stored fraction

Soil

Read also

See extraordinary close-up biota photography and experimental set up in the NanoFASE scientific video:
Nanomaterials in Mesocosms: A Needle in a Haystack