rather than factual data. I tend to believe in finding out exactly what will be required to achive a 5x reduction (50 parts per billion to 10 parts per billion) in arsenic levels rather than depending on hunches. It may or may not be possible to simply extend current technology in order to achive that kind of reduction. I personally believe it's bad science and bad public policy to make law based on hunches. I want to see factual data on the technology required to achieve those reductions and how much it'll cost to implement.

I suggest you read this American Chemical Society article for some more perspective on the issue. I'm sure I can find more such articles. The issue isn't as clear-cut as you seem to believe.