Effects of Amorphous Silica Nanopowders on the Avoidance Behavior of Five Soil Species—A Screening Study

Abstract

Silica nanoparticles (SiO2NPs) are one of the most used in commercial products and biomedical tools, however, their environmental effects have not been fully described. Although negative effects of SiO2NPs on the behavior of freshwater invertebrates have been reported, the knowledge is limited, especially the effect of nanopowders in terrestrial organisms. Accordingly, the aim of the present study is to understand the effects of SiO2NPs on the avoidance behavior of five soil species, whose niche may differ thus contributing to differential harmful SiO2NPs effects. Hence, avoidance assays testing SiO2NPs concentrations of 0, 10, 100, 250, 500 and 1000 mg/kg were performed with Enchytraeus crypticus, Folsomia candida, Tenebrio molitor, Porcellionides pruinosus and Eisenia fetida. SiO2NPs induced different behavioral effects, depending on the invertebrate ecology/habitat, exposure route and physiology. T. molitor, P. pruinosus and F. candida did not avoid contaminated soil; however, E. crypticus and E. fetida significantly avoided SiO2NPs spiked soil. Since these terrestrial worms (oligochaetes) live mostly burrowed in the soil, this can provide greater opportunity for SiO2NPs’ uptake. On the other hand, the other tested organisms mainly living on the upper part of the soil did not avoid the SiO2NPs spiked soil. The avoidance data obtained here also highlight the need for further studies to understand whether (or not) the detected behavioral responses are linked to either neurotransmission processes or sensorial aspects of the biological models.

Functionalized Mesoporous Silicon Nanomaterials in Inorganic Soil Pollution Research: Opportunities for Soil Protection and Advanced Chemical Imaging

“…Likewise, in maize, field applications of SiO 2 -NPs resulted in a large improvement to growth, but interestingly, there were disruptive effects as well with the Si found to induce a pesticide response for the crop during storage [107]. Similarly, some soil invertebrates demonstrate avoidance behaviors to SiO 2 NP Santos et al [108], and it has been shown that they can increase soil bacteria community diversity [109].…”

“…SiO 2 NP place within the top five commercial nanoproducts globally [ 108 , 110 ] with applications ranging from paint stabilizers through to food agents [ 111 ]. Therefore, extensive material flows of SiO 2 NP into the environment are already ongoing [ 111 ].…”

Environmental Hazards of Boron and Vanadium Nanoparticles in the Terrestrial Ecosystem—A Case Study with Enchytraeus crypticus

“…The avoidance response is considered an extremely relevant ecological endpoint, because if the organisms avoid a contaminated soil, the services provided by them will be compromised and the habitat function declines, negatively affecting the soil ecosystem [ 20 , 21 , 22 , 23 ]. On the other hand, if the organisms are not able to avoid the contaminated soil, the hazard on the organisms may be much higher [ 23 , 24 , 25 ].…”

“…The avoidance response is considered an extremely relevant ecological endpoint, because if the organisms avoid a contaminated soil, the services provided by them will be compromised and the habitat function declines, negatively affecting the soil ecosystem [ 20 , 21 , 22 , 23 ]. On the other hand, if the organisms are not able to avoid the contaminated soil, the hazard on the organisms may be much higher [ 23 , 24 , 25 ]. Studies were performed assessing the avoidance behavior of soil organisms (e.g., Eisenia fetida , Enchytraeus crypticus , Porcellionides pruinosus , Porcellio scaber and Tenebrio molitor ) when exposed to NPs-contaminated soil [ 20 , 22 , 23 , 26 , 27 ].…”

“…On the other hand, if the organisms are not able to avoid the contaminated soil, the hazard on the organisms may be much higher [ 23 , 24 , 25 ]. Studies were performed assessing the avoidance behavior of soil organisms (e.g., Eisenia fetida , Enchytraeus crypticus , Porcellionides pruinosus , Porcellio scaber and Tenebrio molitor ) when exposed to NPs-contaminated soil [ 20 , 22 , 23 , 26 , 27 ]. However, there are no studies assessing the avoidance behavior of soil organisms exposed to BNPs or VNPs.…”