That frequency is bang-smack in the middle of the range used by prenatal ultrasound. The UK NHS released a statement discouraging the use of "4d" ultrasonics to make pre-birth videos. This sort of result highlights why this was a good call, if only based on the precautionary principle.
On the flipside, the reason for these recommendations were papers about the effects of ultrasound on tissues, for example (taken at random):
"Basta et al. [46] observed that in single-layer endothelial cells, ultrasound of variable durations between 1.3 MHz and 2.6 MHz with a mechanical index of 1.5 produced increased intracellular oxidation of endothelial cells in addition to endothelial damage under exposure times greater than 30s. This damage lasted up to one hour after exposure. After 15s, it was shown to stagger the DNA and produce leakage of lactate dehydrogenase."
On the flipside, the reason for these recommendations were papers about the effects of ultrasound on tissues, for example (taken at random):
"Basta et al. [46] observed that in single-layer endothelial cells, ultrasound of variable durations between 1.3 MHz and 2.6 MHz with a mechanical index of 1.5 produced increased intracellular oxidation of endothelial cells in addition to endothelial damage under exposure times greater than 30s. This damage lasted up to one hour after exposure. After 15s, it was shown to stagger the DNA and produce leakage of lactate dehydrogenase."