Silicon dioxide and titanium dioxide particles found in human tissues
Creators: name: Peters, Ruud J. B.
name: Oomen, Agnes G.
name: Bemmel, Greet Van
name: Vliet, Loes Van
name: Undas, Anna K.
name: Munniks, Sandra
name: Bleys, Ronald L. A. W.
name: Tromp, Peter C.
name: Brand, Walter
name: Lee, Martijn Van Der
Publisher: name: Taylor & Francis
Year: 2020
Subjects: subject: Space Science
subject: 29999 Physical Sciences not elsewhere classified
subject: FOS: Physical sciences
subject: FOS: Physical sciences
subject: Medicine
subject: Cell Biology
subject: Pharmacology
subject: Biotechnology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: FOS: Earth and related environmental sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: FOS: Chemical sciences
subject: Ecology
subject: FOS: Biological sciences
subject: FOS: Biological sciences
subject: Immunology
subject: FOS: Clinical medicine
subject: FOS: Clinical medicine
subject: Inorganic Chemistry
subject: 60506 Virology

description: Silicon dioxide (silica, SiO<sub>2</sub>, SAS) and titanium dioxide (TiO<sub>2</sub>) are produced in high volumes and applied in many consumer and food products. As a consequence, there is a potential human exposure and subsequent systemic uptake of these particles. In this study we show the characterization and quantification of both total silicon (Si) and titanium (Ti), and particulate SiO<sub>2</sub> and TiO<sub>2</sub> in postmortem tissue samples from 15 deceased persons. Included tissues are liver, spleen, kidney and the intestinal tissues jejunum and ileum. Low-level analysis was enabled by the use of fully validated sample digestion methods combined with (single particle) inductively coupled plasma high resolution mass spectrometry techniques (spICP-HRMS). The results show a total-Si concentration ranging from &lt;2 to 191 mg Si/kg (median values of 5.8 (liver), 9.5 (spleen), 7.7 (kidney), 6.8 (jejunum), 7.6 (ileum) mg Si/kg) while the particulate SiO<sub>2</sub> ranged from &lt;0.2 to 25 mg Si/kg (median values of 0.4 (liver), 1.0 (spleen), 0.4 (kidney), 0.7 (jejunum, 0.6 (ileum) mg Si/kg), explaining about 10% of the total-Si concentration. Particle sizes ranged from 150 to 850 nm with a mode of 270 nm. For total-Ti the results show concentrations ranging from &lt;0.01 to 2.0 mg Ti/kg (median values of 0.02 (liver), 0.04 (spleen), 0.05 (kidney), 0.13 (jejunum), 0.26 (ileum) mg Ti/kg) while particulate TiO<sub>2</sub> concentrations ranged from 0.01 to 1.8 mg Ti/kg (median values of 0.02 (liver), 0.02 (spleen), 0.03 (kidney), 0.08 (jejunum), 0.25 (ileum) mg Ti/kg). In general, the particulate TiO<sub>2</sub> explained 80% of the total-Ti concentration. This indicates that most Ti in these organ tissues is particulate material. The detected particles comprise primary particles, aggregates and agglomerates, and were in the range of 50–500 nm with a mode in the range of 100–160 nm. About 17% of the detected TiO<sub>2</sub> particles had a size &lt;100 nm. The presence of SiO<sub>2</sub> and TiO<sub>2</sub> particles in liver tissue was confirmed by scanning electron microscopy with energy dispersive X-ray spectrometry.