『Abstract
　Nitrate is often seen as an agricultural pollutant of groundwater and so is expected to be at higher concentrations in the groundwaters surrounding a city than in those beneath it. However the difference between rural and urban nitrate concentrations is often small, due to the non-agricultural sources of nitrogen that are concentrated in cities. This paper illustrates the source and significance of non-agricultural nitrogen for groundwater and presents a case study of nitrate loading in the city of Nottingham. Major sources of nitrogen in urban aquifers are related to wastewater disposal (on-site systems and leaky sewers), solid waste disposal (landfills and waste tips). The major sources of nitrogen in the Nottingham area are mains leakage and contaminated land with approximately 38％ each of a total load of 21 kg N ha^-1 year^-1.

Keywords: Urban; Groundwater; Nitrate; Nottingham; Contamination; Leakage』

1. Introduction
2. Non-agricultural sources of nitrogen in groundwater
　2.1. Leakage from water supply and disposal networks
　2.2. On-site sewage disposal
　2.3. Animal waste
　2.4. Contaminated land
　2.5. Industry
　2.6. River and aquifer interaction
　2.7. Atmospheric deposition
　2.8. Urban fertilizer use (gardens, recreational grassland and domestic horticulture)
　2.9. Storm water
　2.10. House building
3. Source and significance of non-agricultural N to groundwater
4. Case study: non-agricultural sources of N in the Nottingham area
　4.1. Background
　4.2. Methods
　4.3. Total recharge and N loading
　4.4. Components of the N loading
　4.5. Results
5. Conclusions
Acknowledgements
References

Table 1. Summary of some published research on non-agricultural sources of groundwater nitrogen a Assuming a concentration of 80 mg N l-1, similar to the concentration of the sewage of Rastatt, Germany (Eiswirth and Holtze（oの頭に¨）, 1997). b The loading was calculated using an estimated recharge and nitrate concentration of 400 mm year-1 and 25 mg NO3-N Loading rates based on a observed loss of 9.5 kg year-1 from a three-person home and a density of five homes ha-1. c All the data, except the loading values, are from (BGS, 1995). The loading values were calculated using the minimum and maximum leachate production estimated in (Gold et al., 1990) (3200 and 18,592 m3 year-1) and the mean NH4 concentration in the leachate. It must be stressed that these values can be very different to those observed due to the different conditions used (rainfall, waste density, landfill age, etc). d Application rate in the winter 1991/92. Nowadays urea based de-icer is not used in commercial airports in the UK. 〔Wakida,F.T. and Lerner,D.N.(2005): Non-agricultural sources of groundwater nitrate: a review and case study. Water Research, 39, 3-16.から〕

Fig. 1. The composition of nitrate load for different periods in the Nottingham urban area. 〔Wakida,F.T. and Lerner,D.N.(2005): Non-agricultural sources of groundwater nitrate: a review and case study. Water Research, 39, 3-16.から〕