Iodine is soluble in water. So, my guess is that most of it is iodine, with a relatively short half-life of about 8 days. Almost none of these reports indicate the concentration, but I would bet that it is far below a toxic dose. Low doses of radiation can actually have healthful benefits, including suppressing cancers (hormesis), so this is not necessarily bad news. However, I know less about ingested radio-isotopes than other modes of exposure. In any case, virtually all hazards associated with radioactive iodine can be mitigated with the ingestion of potassium iodide tablets.
Hence, I see little potential hazard here except for perhaps children. In their case, iodine pills, avoiding milk, and drinking bottled water should be sufficient precaution.