A town that obtains its water supply from deep well drilling discovers toxic wates in the water.?

Question

A town that obtains its water supply from deep well drilling discovers toxic wates in the water. Blame is placed on a toxic waste dumped over 600km from the town. The waste has been dumped into an abandoned mine shaft.
a) How could you prove that toxic wastes had come from the dump site?
b) Assuming the dump site was the source of the pollution, explain how it could have contaminated the town's water supply.

Answer 1

A. For an initial verification, analyze the chemicals in the well and compare with an exact analysis of residue in the mine shaft. To prove that it is possible, put dye or an unusual, harmless substance into the same mine shaft and see if it turns up in the well.

B. Groundwater travels through the aquifer. Some aquifers allow groundwater to travel only very, very slowly (nonporous rock below the aquifer is fairly level so there isn't much of a downhill grade ... or the holes or cracks in the rocks of the aquifer are very small). Other aquifers with gravel instead of rocks allow water to travel through pretty quickly. So the chemicals could have leached into the groundwater and traveled along with the groundwater through the aquifer to the town's well.

Also, the act of drawing water out of the well PULLs the groundwater toward the well.