2 Peter 2:4 (WH): εἰ γὰρ ὁ θεὸς ἀγγέλων ἁμαρτησάντων οὐκ ἐφείσατο, ἀλλὰ σειροῖς ζόφου ταρταρώσας παρέδωκεν εἰς κρίσιν τηρουμένους
I believe that we have to be careful about inferring that the Bible writers directly took language or concepts from non-Jewish literature. For example, does ταρταρόω in 2 Pet 2:4 derive from a non-Jewish source? Should we immediately draw parallel lines between Greek mythology and 2 Peter? That would be a fundamental mistake in my opinion. For example, would it be correct to infer that πλήρωμα in Col 1:19 was directly borrowed from the Gnostics? That would be highly unlikely. I reckon that a similar case could be made for 2 Pet 2:4. Petrine scholars have noted that Tartarus language occurs in Jewish literature (1 Enoch and other works of the Second Temple period): so it's possible that 2 Peter uses language well understood by Jews and Greeks in the 1st century CE. See http://www.augsburgfortress.org/media/downloads/9780800699789Chapter5.pdf
Compare the remarks of Richard Bauckham here: http://www.dougvandorn.com/Bauckham%20Commentary%20and%20Two%20Doug%20Appendices.pdf
Even if 2 Peter 2:4 uses the verb ταρταρώσας, in no way does the usage imply that all the mythic associations of Tartarus should be read into the passage. Tartarus apparently occurs in the LXX too.