Answer: Industrial waste, agricultural runoff, and sewage discharge are all possible sources of water pollution. These pollutants can have detrimental effects on water quality, ecosystems, and human health. Therefore, the correct answer is 4) All of the above
Step-by-step explanation:
1) Industrial waste: Industries produce a wide range of pollutants, including chemicals, heavy metals, and toxins, as byproducts of their processes. If these wastes are not properly treated or disposed of, they can enter nearby water bodies, contaminating the water and causing pollution. For example, factories may release chemicals into rivers, lakes, or oceans, leading to water pollution.
2) Agricultural runoff: When fertilizers, pesticides, and other chemicals are used in agriculture, they can be washed off the fields by rain or irrigation and enter nearby water sources. This runoff carries pollutants such as nutrients (nitrogen and phosphorus) and chemicals, which can cause water pollution. Excessive nutrients in water bodies can lead to algal blooms, oxygen depletion, and harm aquatic life.
3) Sewage discharge: Sewage from human settlements, including domestic wastewater and human waste, is often treated in sewage treatment plants before being discharged into water bodies. However, if the treatment is inadequate or if there are issues with the sewage system, untreated or poorly treated sewage can be directly released into rivers, lakes, or oceans. This can introduce harmful pathogens, bacteria, and pollutants into the water, posing a risk to human health and the environment.