Restricted irrigation is the irrigation of all crops, except vegetables and salad crops eaten uncooked.

Risks to human health due to wastewater-borne pathogens (such as rotavirus, Campylobacter, Cryptosporidium) are estimated by quantitative microbial risk analysis (QMRA) using the scenario of involuntary, but regular, ingestion of wastewater-irrigated soil particles by those working in, or by children playing in, wastewater-irrigated fields.

The same general procedure is used as for the consumption of wastewater-irrigated lettuce, including the same two 'dose–response' equations, described for unrestricted irrigation. The modifications necessary for estimating the health risks associated with restricted (as opposed to unrestricted) irrigation are (a) the ingestion of x–y milligrams of wastewater-contaminated soil per day for n days per year, and (b) zero pathogen die-off in the soil prior to ingestion.

Download the Monte Carlo QMRA program for restricted irrigation (you may need to right click and choose "Save Target As ...")

Read how to enter parameter value ranges and how to do a multi-trial program run

: E-mail either Professor Duncan Mara or, for questions about the Monte Carlo programs, Dr Andrew Sleigh.