Final answer:
Saltwater intrusion due to sea-level rise is a serious environmental concern because it can lead to the contamination of freshwater aquifers. This process jeopardizes the availability and quality of drinking water, agriculture, and ecosystem balance. The correct answer is (c) saltwater intrusion of groundwater could contaminate water supplies.
Step-by-step explanation:
Sea-level rise due to global warming is a critical factor that affects various aspects of the environment, including groundwater systems. One significant issue that arises with sea-level rise is saltwater intrusion, which occurs when salt water moves into areas that were previously occupied by fresh water. This phenomenon can contaminate water supplies, as saltwater can infiltrate groundwater aquifers used for drinking water, industry, and irrigation.
When the sea level rises, coastal aquifers become more vulnerable to saltwater intrusion, particularly when groundwater is pumped heavily from wells, causing a cone of depression that leads to a lowered water table. This imbalance can allow saltwater to seep into freshwater aquifers, resulting in a mix of fresh and salt water—or brackish water. The impact of salinization on agricultural land can significantly reduce soil productivity and eventually lead to the inability to use the land for farming. Moreover, as fresh water becomes scarce, animals, plants, and humans that rely on fresh water for survival will face dire consequences.
Therefore, among the listed options, the most serious concern about saltwater intrusion of groundwater is that it could contaminate water supplies (c). This contamination poses significant threats to the availability and quality of drinking water, the viability of agricultural land, and the overall balance of ecosystems. The spread of marine organisms far inland (a), an increase in the porosity of bedrock (b), and more sinkholes forming (d) are not directly related to the primary concern of saltwater intrusion, which is the contamination of fresh water sources.