Microbial risk assessment of source-separated urine used in agriculture.
A screening-level quantitative microbial risk assessment (QMRA) was undertaken for a urine separating sewerage system. Exposures evaluated included the handling of stored and unstored urine as well as consumption of crops fertilised with urine. Faecal cross-contamination was the source of risk and Campylobacter jejuni, Cryptosporidium parvum and rotavirus were the organisms chosen to represent different groups of enteric pathogens. Accidental ingestion of unstored urine implied a high risk (Pinf = 0.56) for infection from rotavirus whereas the risks for infection from bacteria and protozoa were approximately 1:10 000. After six months storage at 20 degrees C the risk for viral infections by accidental ingestion of 1 ml of urine was < 10(-3), the suggested acceptable risk benchmark. Ingestion of crops contaminated with urine resulted in risks of < 10(-5) after a 3-week (<10(-7) after 4 weeks) withholding period between fertilising and harvesting.
Höglund
Caroline
C
Department of Water and Environmental Microbiology, Swedish Institute for Infectious Disease Control, Solna. caroline.hoglund@smi.ki.se
Stenström
Thor Axel
TA
Ashbolt
Nicholas
N
D000383:Agriculture; D000818:Animals; D001419:Bacteria / Q000302:isolation & purification; D003247:Conservation of Natural Resources; D018562:Disease Transmission, Infectious; D056890:Eukaryota / Q000302:isolation & purification; D018570:Risk Assessment; D014556:Urine / Q000382:microbiology*; D014780:Viruses / Q000302:isolation & purification; D014865:Waste Disposal, Fluid / Q000379:methods*; D014871:Water Microbiology