I've read your stuff very quickly, I think I understood the main idea.
The acid of the rains affects lakes. It produces the separation of the aluminium from the rocks (minerals) into the water. Then it becomes a problem for the fishes that live in the lake, who are affected by the freed aluminium. So mobilised means that normally aluminium doesn't separates from minerals, but it does due to acid rains.we have to explain what is mean't by Aluminium is "mobilised" from minerals into water. But i'm not sure what it means.
Do you guys have any idea?
Of course yes. The fishes are affected, which means that everything that eat fish is also affected. So even humans that fish fishes and eat them may be affected by aluminium. Therefore yes, it turns out to be a problem.Could aluminium poisoning be a problem in lakes affected by acid rain? Why would that be?