PA,
There are many drainages in PA which still suffer from acid rain, outside of coal mining areas.
Yeah, there are geology issues, such as pyrite too. There's also situations where basins HAD a small amount of buffering minerals such as limestone, but have exhausted them through years of acid rain. In those cases, even diminishing the source may not raise the pH of the water. Every stream has to be looked at individually to both determine it's problems and the effectiveness of any solutions. No one size fits all.
But since the 1972 Clean Air act, acid deposition has indeed measurably decreased over time, and a number (not all) streams have benefitted from it. And it stands to reason that further decreases would improve the situation further. In some streams it wouldn't help, in others it would.
And this is one of those things where even environmentalists have to realize that ALL power sources have negative impacts. It may be that expanding one brings some negative consequences, but it also brings positive ones. For instance, with gas, yes, a small % of wells may indeed leak and contaminate groundwater. A small % of many thousands of wells means it will happen, or has happened on multiple occasions in PA. Further, yes, disposal of waste waters may indeed increase the concentration of certain contaminants in our rivers and drinking water.
However, the consequence of NOT doing it is leaving all of these coal plants running. Out of necessity. Which means continued mining activity, continued acid rain, who knows how many respiratory illnesses it is currently causing, other different contaminants staying in our rivers and drinking water, etc.
Not a question of whether a power source is completely safe. None of them are. We are not starting from a pristine condition. The question is whether the proposed source is better than the status quo or the other alternatives.
I could be convinced otherwise and welcome all objective discussions, but from what I've seen my view is this:
Wind and solar are great, but will always be supplementary, and we need more than supplementary. Hydro will continue at current rates, but we're kind of maxed out, and we need more energy. Energy conservation is great, but ultimately demand will continue to rise as population rises, conservation can only slow the rate. So to meet future demand:
Nuclear>>gas>>coal.