Final answer:
Water contamination is commonly caused by human activities, such as agricultural runoff and improper disposal of chemicals. Surface water can be exposed to acid rain and industrial waste, while groundwater can be contaminated by pathogens and agricultural chemicals.
Step-by-step explanation:
Water pollution occurs when contaminants enter water bodies, harming the environment and human health. The most common cause of water contamination is human activities such as agricultural runoff, industrial waste, and improper disposal of hazardous chemicals. Surface water is exposed to acid rain, stormwater runoff, and pesticide runoff, while groundwater can be contaminated by disease-causing pathogens, agricultural chemicals, and underground storage leaks.