What are the biggest sources of water pollution?

Agriculture is the biggest pollutant through the release of nitrate, but mining, deforestation, and urban runoff are all contributors to water pollution. For pollutants outside of human control, floods, drought, and forest fires all release large amounts of toxins into bodies of water.

What are the main things to look for when measuring water quality?

The most common physical measurements of water quality are temperature, conductivity, total dissolved solids, total suspended solids, and turbidity. There are also chemical and biological measurements that can be taken to help us better understand the quality of water.