Simply diverting contaminated mine water to a wetland may do more harm than good. Interestingly, their analysis indicated that low pH and high salinity were primarily responsible for plant dieback, whereas high aluminum and manganese concentrations in the leachate played a less important role. So the issue is not a simple one. Since treatment wetlands receive contaminated mine drainage, it would be expected that animals living in them will be adversely impacted. Remarkably, this doesn't usually appear to be the case.
Metals uptake by wetland plants is one potential point of entry into the food chain.
However, lead in plant leaves was reported to exceed these concentrations. In my investigations, I found that, typically, wetland plants do not take up metals which are accumulated in sediments. For example, the table below compares metal concentrations in two natural wetlands receiving metal-contaminated water. It has the same vegetation as the No Cash and Galkeno wetlands, but does not receive mine water. Notice that the No Cash and Galkeno wetlands have accumulated metals in their sediments, indicating they removed metals from mine water.