I have reviewed a discussion concerning the salt content in the Flint River being directly connected to lead being leached from civic water pipes in Flint, Michigan. Wikipedia has a site dedicated to $\ce{PbCl2}$ and line 1 states that this salt, once formed is insoluble in water, unless that water is heated. Is there a secondary process that results in the lead returning to a form, which can be ingested — after it has been leeched from the wall of a pipe?

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    $\begingroup$ It is not insoluble. It is poorly soluble - enough to poison somebody, though. $\endgroup$ – Ivan Neretin Jan 29 '16 at 9:36
  • $\begingroup$ Supporting Ivan's comment, see this:-chemistry.stackexchange.com/questions/42698/… $\endgroup$ – Nilay Ghosh Jan 29 '16 at 13:40
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    $\begingroup$ All in all the water chemistry is more complicated than you're supposing. // "Insoluble" is a rather poorly defined term in chemistry. As chemists we typically mean that you can't dissolve 1 gram of solute in 100 ml of water. But for lead we're concerned about 0.000000010 grams per ml of water (10 parts per billion). $\endgroup$ – MaxW Jan 29 '16 at 16:42

Lead(II) chloride is not the sitting-at-the-bottom-like-a-brick type of insoluble. Rather it is the well-ma~ybe-I’ll-dissolve-a-little type of insoluble. So enough lead chloride will be dissolved — as Ivan mentioned, enough to poison somebody. Its solubility is given as $10.8~\mathrm{g/l}$ on Wikipedia. There are much less soluble salts like mercury(I) chloride ($2~\mathrm{g/l}$), barium sulfate ($2.4 \cdot 10^{-3}~\mathrm{g/l}$) or silver(I) iodide ($3 \cdot 10^{-6}~\mathrm{g/l}$). Note that for mercury(II) sulfide a solubility is not even given, it is merely termed insoluble (and is the sitting-at-the-bottom-like-a-brick type of an insoluble compound).

All values were taken from Wikipedia and are given at $20~\mathrm{^\circ C}$.

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