Groundwater is important as a source of drinking water, and it supports river flows, lake levels and ecosystems. It contains natural substances dissolved from the soils and rocks that it flows through, and can also be contaminated by human actions on the land surface.
The most common sources of iron in groundwater are naturally occurring, coming for example from the weathering of iron-bearing minerals in rocks.
• Groundwater that is acidic or low in oxygen may have higher iron concentrations. This may arise from overlying peat or thick clays, or effluent seeping from septic tanks, silage clamps, slurry pits, landfills or other sources of pollution.
• In many wells, both private and public, high iron concentrations are related to “on/ off” pumping patterns, which introduces oxygen when the water table is lowered around the well.
• The iron may be found as particles or can be dissolved in the water.