Fenarimol
(endorsed 2011)
Guideline
Based on human health concerns, fenarimol in drinking water should not exceed 0.04 mg/L.
Related chemicals
Fenarimol (CAS 60168-88-9) belongs to the pyrimidine class of fungicides. There are no other pesticides in this class (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, fenarimol would not be a health concern unless the concentration exceeded 0.04 mg/L. Minor 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: Fenarimol is a fungicide for the control of black spot and powdery mildew in apple and pear agricultural crops.
There is at least one registered product containing fenarimol in Australia. Fenarimol products are intended for professional use and are available as concentrated solutions to be applied in diluted form to foliage of target plants using ground and hand-held sprays. Data on currently registered products are available from the Australian Pesticides and Veterinary Medicines Authority.
Exposure sources: The main source of public exposure to fenarimol and its metabolites is residues in food. Residue levels in food produced according to good agricultural practice are generally low.
Agricultural use of fenarimol 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 data on occurrence of fenarimol in Australian waters could be found. In the USA, the estimated environmental concentration in surface water was 0.026 mg/L when not in use for residential applications (USEPA 2002).
Treatment of drinking water
No specific data on the treatment of fenarimol in drinking water have been identified.
Measurement
Fenarimol can be measured by gas chromatography with alkali flame detector, with a detection limit of 4 µg/L (USEPA Method 633.1).
History of the health values
The current acceptable daily intake (ADI) for fenarimol is 0.01 mg per kg of bodyweight (mg/kg bw), based on a no-observed-effect level (NOEL) of 1 mg/kg bw/day from a reproduction study and a long-term (2-year) dietary study in rats. The NOEL is based on liver toxicity in the form of fatty changes in the liver, hepatic nodules, and increased blood glucose in the long-term studies, and increased gestation time in the reproduction studies. The ADI incorporates a safety factor of 100, and was established in 1990.
The previous ADI of 0.025 mg/kg bw was established in 1982, based on a NOEL of 2.5 mg/kg bw/day in a long-term dietary study in rats. The ADI was amended to its present level after submission of reproduction and long-term studies demonstrating lower overall NOELs.
The previous health value was 0.03 mg/L (NHMRC and NRMMC 2004).
Health considerations
Metabolism: Fenarimol was poorly absorbed from the gastrointestinal tract of rats. The absorbed fraction was extensively metabolised (>30 metabolites) with excretion mostly via the faeces within 7 days.
Acute effects: Fenarimol has low acute oral and dermal toxicity. It is not a skin sensitiser.
Short-term effects: Short-term (2-3 week) dietary studies in rats and mice reported increased P-450 liver enzymes at 20 mg/kg bw/day in mice, and increased relative liver weight and centrilobular hypertrophy at 40 mg/kg bw/day in mice and rats. Similar changes were reported in 3-month dietary studies in mice, rats and dogs.
Long-term effects: Long-term (2-year) dietary studies were conducted in mice and rats. In rats, there were fatty changes in the liver, hepatic nodules, and increased blood glucose at doses of 5 mg/kg bw/day. The lowest NOEL was 1.3 mg/kg bw/day in rats, and this NOEL is partly the basis for the current ADI.
Carcinogenicity: Based on a 2-year study in mice and rats, there is no evidence of carcinogenicity for fenarimol.
Genotoxicity: Fenarimol is not considered to be genotoxic, based on in vitro and in vivo short-term studies.
Reproductive and developmental effects: A 3-generation reproduction study in rats reported an increased gestation period at doses of 5 mg/kg bw/day, and decreased pregnancy rate and litter size at doses of 13 mg/kg bw/day. The NOEL was 1.07 mg/kg bw/day and this NOEL is partly the basis for the current ADI. In developmental toxicity studies in rats and rabbits, there was no evidence of effects on foetal development.
Poisons Schedule: Fenarimol is included in Schedule 5 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 0.04 mg/L for fenarimol was determined as follows:
where:
1.07 mg/kg bw/day is the NOEL based on long-term (2-year) dietary studies, and a 3-generation reproduction study in rats.
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.
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.
NHMRC (National Health and Medical Research Council), NRMMC (Natural Resources Management Ministerial Council) (2004). Australian Drinking Water Guidelines. National Water Quality Management Strategy, Paper 6. NHMRC and NRMMC.
Tomlin CD (ed) (2006). The Pesticide Manual: a world compendium, 14th edition, British Crop Production Council, UK.
USEPA (United States Environmental Protection Agency) (2002). Report on FQPA Tolerance Reassessment Progress and Risk Management Decision. USEPA.
USEPA Method 633.1. The Determination of Neutral Nitrogen-Containing Pesticides in Municipal and Industrial Wastewaters. United States Environmental Protection Agency.
Last updated
