Government Under Fire as Radiation Is Found in Milk, Rain

You misinterpret what half life means. Half life is the time it takes for an amount or concentration of a substance to decrease by half. That means that after 8 days, half of the Iodine 131 remains. Then after 18 days, 1/4 remains. Then after 24 days 1/8 remains, etc. I thought schools taught this in middle school or something. Guess schools these days are worse than I thought.

But that assumes no extra iodine 131 is added to the system, but it is very possible for more to come from japan with the conditions the plants are still in. And only a small amount of people will experienience a direct sickness from this iodine (either by drinking rainwater, or being very unlucky as radiation is like a lottery), and the main concern is the wild life or animals that rely on rain water, or animals that consume substances directly affected by the radiation (ex. a cow eating grass saturated in radiated water).

Oh? I thought half the "alarming" amount was enough to be ignored. Apparently we know half-life by book definition but conveniently forget how significant HALF of something is.
If you insist to go by guidelines, then let's work some numbers out.

Radioactivity = (mass/atomic mass)*Avogadro*(ln(2)/half-life) (in Bq)
=> radioactivity is directly proportional to the substance's mass, in other words the radioactivity decays exponentially in accordance to the decaying of the mass itself.
in other words:
radioactivity left after T time = initial radioactivity*(1/2)^(t/half-life)
<=> 0.111Bq = 20Bq*(1/2)^(t/half-life)
<=> (1/2)^(t/half-life) = 0.00555
<=> t/half-life = log(1/2) 0.00555 = ln(0.00555)/ln(1/2) = 7.49329651
<=> time required to reach desired radioactivity = 8*7.49329651 = 59.9463721 days = barely 2 months.
For the average (and not peak) values, the time span is barely: 8*(ln(0.111/5)/ln(1/2)) = 43.9463721 days = 6 weeks.
Assuming I'm not making any incorrect assumptions. (lol)

Fair enough to me, I don't like milk much. Know this though, after every week's time, the threat reduces by half, so essentially, as I initially suggested, after 8~10 days, the hype should already be 8 feet under. That is if you go out and scoop rainwater for daily consumption, or assuming that the transfer of radioactivity from rainwater -> grass or from grass -> cow's stomach or from cow's stomach -> other parts of body and essentially its milk is 100%.

Oh and, by the way, Xenon131 is a stable isotope if you're wondering.