How do chemical fertilisers and pesticides land up in rivers and dams?
Chemical fertilizers and pesticides can end up in rivers and dams through various pathways:
1. Runoff: When chemical fertilizers and pesticides are applied to agricultural fields, rainwater can wash them off the soil surface and carry them into nearby rivers and dams. This runoff occurs when the soil is unable to absorb all the applied fertilizers and pesticides, and excess amounts flow away with the water.
2. Erosion: Improper land management practices such as excessive tilling, overgrazing, or deforestation can lead to soil erosion. As the top layer of soil is eroded, it can transport chemical fertilizers and pesticides that were present on the surface into rivers and dams.
3. Leaching: Chemical fertilizers and pesticides may infiltrate into the soil and reach the groundwater system. Over time, they can travel through the soil, ultimately reaching rivers and dams through underground pathways, such as underground springs or riverbank seepage.
4. Spills and accidents: Accidental spills or improper disposal of chemical fertilizers and pesticides during transportation, storage, or application can directly release these substances into nearby water bodies, contaminating rivers and dams.
5. Drift and spray drift: During the application of pesticides, wind can carry small droplets or particles of the chemicals away from the target area. These can then be transported by air currents and ultimately deposit into rivers and dams.
Once chemical fertilizers and pesticides enter rivers and dams, they can have detrimental effects on aquatic ecosystems, including the potential for water pollution, reduced water quality, harm to aquatic organisms, and disruption of the food chain. It is essential to adopt sustainable agricultural practices and responsible handling and disposal methods to reduce their impact on water systems.