Iprodione
(endorsed 2011)
Guideline
Based on human health concerns, iprodione in drinking water should not exceed 0.1 mg/L.
Related chemicals
Iprodione (CAS 36734-19-7) belongs to the dicarboximide class of chemicals. Another pesticide in this class is procymidone (Tomlin 2006).
Human risk statement
With good water quality management practices, the exposure of the general population is expected to be well below levels that may cause health concerns.
If present in drinking water as a result of a spillage or through misuse, iprodione would not be a health concern unless the concentration exceeded 0.1 mg/L. Excursions above this level would need to occur over a significant period to be a health concern, as the health-based guideline is based on long-term effects.
With good water quality management practices, pesticides should not be detected in source waters used for drinking water supplies. Persistent detection of pesticides may indicate inappropriate use or accidental spillage and investigation is required in line with established procedures in the risk management plan for the particular water source.
General description
Uses: Iprodione is a fungicide for the control of disease in a wide range of agricultural crops.
There are registered products that contain iprodione in Australia. The products are intended for professional use and are available as a suspension concentrate, suspoemulsion or wettable granule formulation. They are applied as either a dilute or concentrated spray to crops and turf, or as a liquid seed dressing. Data on currently registered products are available from the Australian Pesticides and Veterinary Medicines Authority.
Exposure sources: The main source of public exposure to iprodione is residues in food. Residue levels in food produced according to good agricultural practice are generally low.
Agricultural use of iprodione may potentially lead to contamination of source waters through processes such as run-off, spray drift or entry into groundwater.
Typical values in Australian drinking water
No reports of iprodione in Australian drinking waters were found.
Treatment of drinking water
No reports of the treatment of iprodione in drinking water were found. However, research indicates that ultraviolet photolysis and advanced oxidation are likely to be effective treatment processes (Garbin et al. 2007).
Measurement
Iprodione can be measured in water by solid phase extraction followed by high performance liquid chromatography with diode array detection (D’Archivio et al. 2007). The reported limit of quantitation for the technique in groundwater is 0.05 µg/L.
History of the health values
The current acceptable daily intake (ADI) for iprodione is 0.04 mg per kg body weight (mg/kg bw), based on a no-observed-effect level (NOEL) of 4 mg/kg bw/day from a 1-year dietary study in dogs. The NOEL is based on changes in organ weights and haematological parameters at 25 mg/kg bw/day. The ADI incorporates a safety factor of 100 and it was established in 1986.
A health value has not been previously established by NHMRC.
Health considerations
Metabolism: Iprodione is extensively metabolised and excreted in the urine and faeces, almost completely within 96 hours.
Acute effects: Iprodione has low acute oral and dermal toxicity. It is not a skin sensitiser.
Short-term effects: Short-term studies in mice and dogs identified the liver as the major target organ. In short-term dietary studies in mice, reduced bodyweight gain and histopathological changes in the liver, testes, kidney and urinary bladder were seen at 900 mg/kg bw/day. In a 5-month dietary study in rats, no treatment-related adverse effects were reported at the highest dose tested of 50 mg/kg bw/day. In a 3-month dietary study in dogs, there was slight liver hypertrophy and changes in clinical chemistry at 180 mg/kg bw/day.
Long-term effects: In 1- and 2-year dietary studies in mice and rats, there were changes in spleen and kidney histopathology in rats at 12 mg/kg bw/day, testicular interstitial cell hyperplasia in both mice and rats at 115 mg/kg bw/day, changes in liver histopathology in mice at 115 mg/kg bw/day, and increased organ weights in mice at 575 mg/kg bw/day.
In a 1-year dietary study in dogs, changes in liver and prostate weights and histological changes within the adrenal glands, kidneys, liver and urinary bladder were observed at 25 mg/kg/bw/day. At 151 mg/kg bw/day, there were also changes in haematological and clinical chemistry parameters. The NOEL was 4 mg/kg bw/day and this is the basis for the current ADI.
Carcinogenicity: In mice, there was an increased incidence of benign and malignant liver cell tumours and ovarian luteomas at 575 mg/kg bw/day. In rats, there was an increased incidence of benign testicular tumours (interstitial cell tumours and bilateral interstitial cell tumours) at 65 mg/kg bw/day. These effects were noted at dose levels well in excess of the likely level of human exposure in drinking water.
Genotoxicity: Iprodione is not considered to be genotoxic, based on in vitro and in vivo short-term studies.
Reproductive and developmental effects: In a 3-generation reproduction study in rats, there was no effect on reproductive parameters at the highest dose tested (119 mg/kg bw/day), however, the litter size and pup bodyweights were reduced in the third generation at the high dose in the absence of maternal toxicity. In a separate 2-generation study in rats, there were no effects on reproductive parameters or on pups. In developmental studies in rats and rabbits, there was no evidence of effects on foetal development at doses that did not result in maternotoxicity.
Poisons Schedule: Iprodione is considered not to require control by scheduling due to its low toxicity and is therefore included in Appendix B of the Standard for the Uniform Scheduling of Medicines and Poisons No.1, 2010 (the Poisons Standard)(DoHA 2010). Current versions of the Poisons Standard should be consulted for further information.
Derivation of the health-based guideline
The health-based guideline of 0.1 mg/L for iprodione was determined as follows:
where:
4 mg/kg bw/day is the NOEL based on a long-term (1-year) dietary study in dogs.
70 kg is taken as the average weight of an adult.
0.1 is a proportionality factor based on the assumption that 10% of the ADI will arise from the consumption of drinking water.
2 L/day is the estimated maximum amount of water consumed by an adult.
100 is the safety factor applied to the NOEL derived from animal studies. This safety factor incorporates a factor of 10 for interspecies extrapolation and 10 for intraspecies variation.
References
NOTE: The toxicological information used in developing this fact sheet is from reports and data held by the Department of Health, Office of Chemical Safety.
D’Archivio AA, Fanelli M, Mazzeo P, Ruggieri F (2007) Comparison of different sorbents for multiresidue solid-phase extraction of 16 pesticides from groundwater coupled with high-performance liquid chromatography. Talanta, 71(1):25-30.
DoHA (2010) The Poisons Standard; Schedule 1-Standard for the Uniform Scheduling of Medicines and Poisons, Department of Health and Ageing, Commonwealth of Australia, Canberra.
Garbin JR, Milori D, Simoes ML, da Silva WTL, Neto LM (2007) Influence of humic substances on the photolysis of aqueous pesticide residues. Chemosphere, 66(9):1692-1698.
Tomlin CD (ed) (2006). The Pesticide Manual: a world compendium, 14th Edition, British Crop Production Council, UK.
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