What is the typical runoff result when water comes into contact with pyrite at the earth's surface?

When water interacts with pyrite at the Earth's surface, it typically leads to the formation of acidic runoff. Pyrite, also known as fool's gold, is an iron sulfide mineral. When exposed to oxygen and moisture, pyrite undergoes a process called oxidation. This chemical reaction results in the release of sulfuric acid and various iron oxides. The production of sulfuric acid lowers the pH of the water, making it acidic.

Acidic runoff can have significant environmental consequences, particularly in mining regions where pyrite is commonly found. This acid drainage can harm aquatic ecosystems, as the lower pH can be toxic to fish and other organisms, and it can lead to the leaching of heavy metals from surrounding rocks into water sources. Understanding the behavior of water in contact with pyrite is crucial for environmental management and mitigation of acid mine drainage issues.