Answer:
Since the origin of humans on this planet, they have been trying their best to make their lives easier on this planet. In doing so, human activities have some how heavily damaged the Earth. Many day to day activities of humans are dangerous for the Earth.
Some of the consequences of human activities on the Earth's fresh water are :
Extinction of many aquatic species:
The water consumed by humans comes from the fresh water oceans. As the population of humans is increasing enormously, the water from the oceans is being consumed at dangerous levels. This has caused many species of aquatic animals to become extinct or to be at a verge of extinction as they do not have a habitat to survive or reproduce.
Pollution:
Many heavy industries, house sewage, farmers dispose waste into the fresh water. Hence, killing aquatic animals and polluting the fresh water ecosystems.