Table 1.

Typical concentrations of sources of dissolved NH4+ to groundwater.

OccurrenceReferenceTypical concentration (mg(NH4-N) l−1)
Pumped urban groundwater (Birmingham)Ford & Tellam 1994<0.01– 0.93
Sewage effluent (tertiary treatment)Horan 19901–5
Sewage effluent (secondary treatment)Horan 199015–25
Untreated sewageHoran 199020–40
Typical landfill leachate (recent wastes)Department of the Environment 1995800
Typical gasworks soilCL:AIRE 2003up to 1000 mg kg−11
Groundwater at cemeteries or graveyardsEnvironment Agency 1999aup to 400
Foot and mouth epidemic mass burial leachateEnvironment Agency 2003c1000–7000
  • For comparison, the current UK Environmental Quality Standard (for ammonia) for freshwater salmonid fisheries is 0.015 mg(NH3-N) l−1 and the Drinking Water Standard (for ammonium) is 0.39 mg(NH4-N) l−1.

  • 1Soil concentration; no reported data on representative groundwater concentrations.