In both flood and drought situations, contamination of soil, water and air become more enhanced Droughts for example affect water sediment, taste, odor and pathogens in poor quality water which is the only available water during droughts. Regional plants lining the river banks of water sources have been replaced by drought resistant plants. While regional plants absorb bacteria and metals from rain runoff and thereby enhance the quality of water. These however are being replaced by drought resistant plants which do not filter or absorb as well the impurities that are found in streams, rivers and lakes.
In the case of floods, soil erosion on agricultural land will often carry also many of the pesticides, chemicals etc that are often used by farms. Flood water often carries material from eroded river banks and often degrades the quality of the water. Also, sediment is often carried great distances and after depositing on bottoms of rivers and streams. This sedimentation then impacts local marine life and has in the past destroyed many ecosystems.
