Issues currently complicating the risk assessment of synthetic amorphous silica (SAS) nanoparticles after oral exposure

Abstract

Synthetic amorphous silica (SAS) is applied in food products as food additive E 551. It consists of constituent amorphous silicon dioxide (SiO 2 ) nanoparticles that form aggregates and agglomerates. We reviewed recent oral toxicity studies with SAS. Some of those report tissue concentrations of silicon (Si). The results of those studies were compared with recently determined tissue concentrations of Si (and Si-particles) in human postmortem tissues. We noticed inconsistent results of the various toxicity studies regarding toxicity and reported tissue concentrations, which hamper the risk assessment of SAS. A broad range of Si concentrations is reported in control animals in toxicity studies. The Si concentrations found in human postmortem tissues fall within this range. On the other hand, the mean concentration found in human liver is higher than the reported concentrations causing liver effects in some animal toxicity studies after oral exposure to SAS. Also higher liver concentrations are observed in other, negative animal studies. Those inconsistencies could be caused by the presence of other Si-containing chemical substances or particles (which potentially also includes background SAS) and/or different sample preparation and analytical techniques that were used. Other factors which could explain the inconsistencies in outcome between the toxicity studies are the distinct SAS used and different dosing regimes, such as way of administration (dietary, via drinking water, oral gavage), dispersion of SAS and dose. More research is needed to address these issues and to perform a proper risk assessment for SAS in food. The current review will help to progress research on the toxicity of SAS and the associated risk assessment.

Grouping of orally ingested silica nanomaterials via use of an integrated approach to testing and assessment to streamline risk assessment

“…Finally, it may be worth mentioning that the risk assessment of oral exposure to amorphous silica NFs present in foods remains greatly uncertain due to technical drawbacks (silicon detection, contaminants, exposure mode) that must still be solved [ 53 ].…”

Analysis and Evaluation of Heavy Metal Pollution in Kosasthalaiyar River near Ennore Creek Using Geo Statistical Approach

“…The presence of silica in sediments and soil helps strengthen the plant's cells and reduce water loss in agriculture. It also increases the plant tolerance, frost, and lodging action on the plants (Brand et al 2021;Barbhuiya et al 2021). In general, sandy soil contain a higher percentage of silica content.…”

Oral Toxicokinetics, Tissue Distribution, and 28-Day Oral Toxicity of Two Differently Manufactured Food Additive Silicon Dioxides

“…Recent some research showed the potential toxicity of SAS in terms of inflammation of the intestinal wall and neurotoxicity [ 15 , 16 , 17 , 18 ]. Contradictory in vivo toxicity results were also reported, showing the low oral toxicity of SAS [ 18 , 19 , 20 , 21 ].…”