4. What is a common cause of saltwater intrusion? \( \begin{array}{ll}0 & \text { A) Overuse of chemical fertilizers } \\ \begin{array}{ll}\text { - } & \text { B) Excessive groundwater pumping } \\ 0 & \text { C) Natural rainfall patterns } \\ 0 & \text { D) Surface runoff }\end{array}\end{array} \).

Excessive groundwater pumping is like a thirsty sponge soaking up water from its surroundings, and when groundwater levels drop, it opens the door for saltwater to creep in from nearby bodies of water. This phenomenon often occurs in coastal regions where aquifers are close to the sea, and if not managed properly, the results can be quite salty! To avoid saltwater intrusion, consider monitoring your groundwater levels carefully and adopt sustainable practices such as rainwater harvesting or using alternative water sources. One common mistake is not accounting for environmental changes—droughts or changes in land use can exacerbate the problem, leading to serious long-term impacts on local ecosystems and drinking water supplies.