Drinking water extraction sites where nitrate is classified as (potential) problem dust

This map shows which extractions nitrate has been found as a potential or current problem substance. The map is based on information from the area files for drinking water extraction. Nitrate is a problem for groundwater extraction, not surface water extraction. Nitrate enters groundwater in particular through water that leaches out of the root zone of agricultural land. Due to denitrification, nitrate can be broken down. If pyrite oxidation occurs, the sulfate content as well as the levels of heavy metals such as nickel may also increase. This can also increase the hardness.