Final answer:
Environmentalists are concerned about the potential pollution and depletion of a lake used as a city's water supply, the risk of subsidence from aquifer depletion, and the disproportionate impact on marginalized communities.
Step-by-step explanation:
Environmentalists are concerned about the use of a lake as a major water supply for a new city because it poses significant risks of water pollution and depletion of this vital freshwater source. Freshwater is already in short supply and the introduction of wastewater from sewage into lakes can lead to pollution affecting both the environment and human health. In addition, drawing water from underground aquifers can lead to subsidence, which may cause structural damage to buildings. The increase in population density associated with urbanization often leads to greater demands on water resources and can exacerbate the pollution of nearby water bodies with untreated human waste, chemicals, and other pollutants. This not only affects the water quality but can also distort the food chain, as toxins like mercury get bioaccumulated. Lastly, history has shown that discriminatory practices often result in marginalized communities suffering disproportionately from environmental problems such as water pollution.