Leaching of human pathogens in repacked soil lysimeters and contamination of potato tubers under subsurface drip irrigation in Denmark

Anita Forslund, Finn Plauborg, Mathias Neumann Andersen, Bo Markussen, Anders Dalsgaard

Research output: Contribution to journalJournal articleResearchpeer-review


The risk for contamination of potatoes and groundwater through subsurface drip irrigation with low quality water was explored in 30 large-scale lysimeters containing repacked coarse sand and sandy loam soils. The human pathogens, Salmonella Senftenberg, Campylobacter jejuni and Escherichia coli O157:H7, and the virus indicator Salmonella Typhimurium bacteriophage 28B, were added weekly through irrigation tubes for one month with low irrigation rates (8 mm per week). In the following six months lysimeters were irrigated with groundwater free of pathogens. Two weeks after irrigation was started, phage 28B was detected in low concentrations (2 pfu ml(-1)) in leachate from both sandy loam soil and coarse sand lysimeters. After 27 days, phage 28B continued to be present in similar concentrations in leachate from lysimeters containing coarse sand, while no phage were found in lysimeters with sandy loam soil. The added bacterial pathogens were not found in any leachate samples during the entire study period of 212 days. Under the study conditions with repacked soil, limited macropores and low water velocity, bacterial pathogens seemed to be retained in the soil matrix and died-off before leaching to groundwater. However, viruses may leach to groundwater and represent a health risk as for some viruses only few virus particles are needed to cause human disease. The bacterial pathogens and the phage 28B were found on the potato samples harvested just after the application of microbial tracers was terminated. The findings of bacterial pathogens and phage 28 on all potato samples suggest that the main risk associated with subsurface drip irrigation with low quality water is faecal contamination of root crops, in particular those consumed raw. (C) 2011 Elsevier Ltd. All rights reserved.
Original languageEnglish
JournalWater Research
Issue number15
Pages (from-to)4367-4380
Number of pages14
Publication statusPublished - 2011
Externally publishedYes


  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Ecological Modeling
  • Contaminated water
  • Human pathogens
  • Leaching
  • Potatoes
  • Repacked soil lysimeters
  • Subsurface irrigation
  • Bacterial pathogens
  • Campylobacter jejuni
  • Denmark
  • Escherichia coli O157:H7
  • Faecal contamination
  • Human disease
  • Irrigation rates
  • Leachate samples
  • Leachates
  • Low concentrations
  • Low qualities
  • Low water
  • Macropores
  • Microbial tracers
  • Potato tubers
  • Root crops
  • Salmonella Senftenberg
  • Salmonella Typhimurium
  • Sandy loam soils
  • Soil matrices
  • Subsurface drip irrigation
  • Bacteriology
  • Contamination
  • Escherichia coli
  • Groundwater
  • Groundwater pollution
  • Health risks
  • Lysimeters
  • Pathogens
  • Salmonella
  • Soil conditioners
  • Soil surveys
  • Soils
  • Subirrigation
  • Viruses
  • Soil pollution
  • ground water
  • bacterium
  • bioindicator
  • drip irrigation
  • environmental risk
  • food consumption
  • groundwater
  • groundwater pollution
  • harvesting
  • health risk
  • irrigation system
  • leachate
  • leaching
  • lysimeter
  • pathogen
  • potato
  • public health
  • sandy loam
  • tracer
  • tuber
  • virus
  • water quality
  • article
  • bacterium contamination
  • irrigation (agriculture)
  • nonhuman
  • priority journal
  • Salmonella typhimurium
  • water contamination
  • Agricultural Irrigation
  • Environmental Monitoring
  • Escherichia coli O157
  • Humans
  • Soil
  • Soil Microbiology
  • Soil Pollutants
  • Solanum tuberosum
  • Water Pollutants
  • Bacteria (microorganisms)
  • Salmonella enterica subsp. enterica serovar Senftenberg
  • Food technology - General and methods
  • Physiology and biochemistry of bacteria
  • Bacteria, Eubacteria, Microorganisms
  • Angiosperms, Dicots, Plants, Spermatophytes, Vascular Plants
  • irrigation rate
  • low water velocity
  • low quality water
  • Food security, food quality and human health
  • Irrigation and drainage

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