Like most of us, I'm fairly well versed on the risks and available treatments to make backcountry water contaminated by bacteria, cysts and viruses safe to drink. But I wonder about dealing with water that may be contaminated by various industrial chemicals, fertilizers, and all the effluvia that may find its way into surface and subsurface waters, especially in the frontcountry.

This may be a particular concern in the aftermath of disasters. Obviously, there are many such contaminants that simply cannot be dealt with by any any reasonable filtration or treatment process, but I wonder if there any available practical ways to recognize, identify or test for any of these contaminants, short of just giving some to someone I don't particularly like and seeing what happens?

Any thoughts appreciated. Thanks!