As indicated by AMEC in its 2009 report, chloride in groundwater is a good indicator of the presence of leachates. We know that chloride of late has been increasing in wells outside the perimeter of the Cache Creek landfill, so it’s a good bet that leachates (none of them recommended as thirst-quenchers on the warm sunny afternoons we have been having recently) are present in the groundwater going down to the Bonaparte too, and in increasing amounts.
Another thing showing up, in quantities that bode little good for anyone, is methane. Methane concentrations exceeding the lower explosive level of 25% were apparently detected in areas outside the landfill in 2012 and, it seems, are still being detected.
So the concerns raised by Esther Darlington MacDonald (June 27) are not trivial by any means. It would not be a bad idea, in fact, for Mr. Whitehead and the Cache Creek Advisory Committee to take a close look at what is going on and let us know if these are things that may go POOF on us, or if these are things we needn’t worry about at all.