https://www.iaea.org/topics/response/fukushima-daiichi-nuclear-accident/fukushima-daiichi-alps-treated-water-discharge/faq

It's all here.

This is a non issue. The ALPS water has been treated for every radio isotope except for tiritum, which is harmless. The release of this water will be a great case study for studying pacific ocean currents and that's about it.