Advanced

Förekomst och spridning av kväveföroreningar i grundvatten, En fallstudie av Köpinge - Vrams vattenförenings grundvattenuttag på Kristianstadslätten

Andersson, Pontus LU (2012) MVEM11 20101
Studies in Environmental Science
Abstract
The aim of this Master’s thesis is to evaluate what possible impact an increased use of groundwater may have on the spread of nitrogen pollution. The work is part of a larger project where Sweco Environment AB assists about 40 farmers in the “Köpinge - Vrams vattenförening” to apply for authorization for groundwater use in agricultural irrigation. The work was performed in three steps: a literature review, a statistical evaluation of historical and current nitrogen pollutions in the area, and a modelling of how future water use may change the nitrogen pollution.
The study area is located on Kristianstad plain in NE Skåne in close proximity to the Vramsån River. In geological terms the area is a bedrock basin filled by younger sedimentary... (More)
The aim of this Master’s thesis is to evaluate what possible impact an increased use of groundwater may have on the spread of nitrogen pollution. The work is part of a larger project where Sweco Environment AB assists about 40 farmers in the “Köpinge - Vrams vattenförening” to apply for authorization for groundwater use in agricultural irrigation. The work was performed in three steps: a literature review, a statistical evaluation of historical and current nitrogen pollutions in the area, and a modelling of how future water use may change the nitrogen pollution.
The study area is located on Kristianstad plain in NE Skåne in close proximity to the Vramsån River. In geological terms the area is a bedrock basin filled by younger sedimentary rock. In general the crystalline bedrock is overlain by clay, followed by unconsolidated glauconite sand and above that a mix of limestone and sandstone, all of Cretaceous age. The sedimentary rocks are followed by a complex sequence of Quaternary deposits. The typical stratigraphy of the latter consists of a layer of till, followed by glaciofluvial deposits and on top glacial clay and/or beach deposits. This geological stratigraphy makes it possible to extract larger amounts of water from both the sedimentary rock and some of the Quaternary deposits.
The study area is characterised by large-scale farming at which large quantities of fertilizers is used (large load of nitrogen). This, combined with a high hydraulic conductivity in the topsoil and the growth of certain corps, especially root vegetables, have resulted in nitrogen, especially nitrate, polluted groundwater. Since large intake of nitrate and nitrite have negative effects on human health, this affects the waters quality and suitability as a drinking water.
The main factors that determine the risk and extent of nitrogen pollution of groundwater are: water transport (in- or outflow area), nitrogen load, soil type, climate, plant uptake and biological- and chemical reduction.
The fact that nitrate contamination of groundwater is a problem in the area has been known for some time and also this study revealed high nitrate levels in the groundwater. The evaluation of the last measured nitrate level in wells in the area shows that 28 % of all wells that take water from the Quaternary deposits and 14 % of all drilled wells into sedimentary rocks have nitrate levels above the guideline value (50 mg NO3-/ l) for drinking water according to Swedish standards (SOSFS 2003:17).
The evaluation also shows that the nitrate level appears to be high in all investigated sites and there are no major geographic differences. The nitrogen level is in most sites lower today than in the 1970s and the trend of decreased nitrate pollution has also been substantiated by regression analysis of nitrate concentration over time at the different sites.
For nitrite and ammonium we only observed sporadic and locally elevated levels. This indicates that both further studies and measures should focus on nitrate.
The modeling results show only low concentrations of nitrate in the ground water. Comparisons between the calculated nitrate concentrations with and without increased agricultural irrigation dose not differ much. The result indicates that nitrate load and nitrate reduction is more important for the concentration then the extraction of water.
Overall the study shows that pollution in the study area is a matter of concern, but that the trend of pollution over the last decade shows lowering levels. This can be seen as an indication that the increased groundwater extraction for irrigation purposes in the future is not a major threat to groundwater quality. (Less)
Please use this url to cite or link to this publication:
author
Andersson, Pontus LU
supervisor
organization
course
MVEM11 20101
year
type
H2 - Master's Degree (Two Years)
subject
language
Swedish
id
3223765
date added to LUP
2012-12-04 10:48:26
date last changed
2013-01-14 11:08:38
@misc{3223765,
  abstract     = {The aim of this Master’s thesis is to evaluate what possible impact an increased use of groundwater may have on the spread of nitrogen pollution. The work is part of a larger project where Sweco Environment AB assists about 40 farmers in the “Köpinge - Vrams vattenförening” to apply for authorization for groundwater use in agricultural irrigation. The work was performed in three steps: a literature review, a statistical evaluation of historical and current nitrogen pollutions in the area, and a modelling of how future water use may change the nitrogen pollution. 
The study area is located on Kristianstad plain in NE Skåne in close proximity to the Vramsån River. In geological terms the area is a bedrock basin filled by younger sedimentary rock. In general the crystalline bedrock is overlain by clay, followed by unconsolidated glauconite sand and above that a mix of limestone and sandstone, all of Cretaceous age. The sedimentary rocks are followed by a complex sequence of Quaternary deposits. The typical stratigraphy of the latter consists of a layer of till, followed by glaciofluvial deposits and on top glacial clay and/or beach deposits. This geological stratigraphy makes it possible to extract larger amounts of water from both the sedimentary rock and some of the Quaternary deposits. 
The study area is characterised by large-scale farming at which large quantities of fertilizers is used (large load of nitrogen). This, combined with a high hydraulic conductivity in the topsoil and the growth of certain corps, especially root vegetables, have resulted in nitrogen, especially nitrate, polluted groundwater. Since large intake of nitrate and nitrite have negative effects on human health, this affects the waters quality and suitability as a drinking water. 
The main factors that determine the risk and extent of nitrogen pollution of groundwater are: water transport (in- or outflow area), nitrogen load, soil type, climate, plant uptake and biological- and chemical reduction.
The fact that nitrate contamination of groundwater is a problem in the area has been known for some time and also this study revealed high nitrate levels in the groundwater. The evaluation of the last measured nitrate level in wells in the area shows that 28 % of all wells that take water from the Quaternary deposits and 14 % of all drilled wells into sedimentary rocks have nitrate levels above the guideline value (50 mg NO3-/ l) for drinking water according to Swedish standards (SOSFS 2003:17).
The evaluation also shows that the nitrate level appears to be high in all investigated sites and there are no major geographic differences. The nitrogen level is in most sites lower today than in the 1970s and the trend of decreased nitrate pollution has also been substantiated by regression analysis of nitrate concentration over time at the different sites.
For nitrite and ammonium we only observed sporadic and locally elevated levels. This indicates that both further studies and measures should focus on nitrate. 
The modeling results show only low concentrations of nitrate in the ground water. Comparisons between the calculated nitrate concentrations with and without increased agricultural irrigation dose not differ much. The result indicates that nitrate load and nitrate reduction is more important for the concentration then the extraction of water. 
Overall the study shows that pollution in the study area is a matter of concern, but that the trend of pollution over the last decade shows lowering levels. This can be seen as an indication that the increased groundwater extraction for irrigation purposes in the future is not a major threat to groundwater quality.},
  author       = {Andersson, Pontus},
  language     = {swe},
  note         = {Student Paper},
  title        = {Förekomst och spridning av kväveföroreningar i grundvatten, En fallstudie av Köpinge - Vrams vattenförenings grundvattenuttag på Kristianstadslätten},
  year         = {2012},
}