Here are the answers to your true or false statements:
-
FALSE - Subsidence is typically caused by the collapse of underground voids, such as those formed by mining activities or the drainage of groundwater, rather than flooding caves.
-
FALSE - Pollution plumes can spread at varying rates, and many can spread relatively quickly, often leaving limited time for finding alternate water supplies.
-
FALSE - Many chemical contaminants can be difficult to remove from groundwater and aquifers; some may require extensive treatment processes.
-
TRUE - If the recharge areas of confined aquifers are polluted, the contaminants can eventually make their way into the aquifer, leading to pollution there as well.