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Proposals to Amend (No. 2) the New Zealand (Maximum Residue Limits of Agricultural Compounds) Food Standards 2008

8 Proposal set an MRL for 1-Naphthylacetic acid

It is proposed that an MRL is set for 1-naphthylacetic acid when used as a plant growth regulator for Satsuma and encore mandarin varieties. It is proposed that Schedule One of the NZ (MRL) Food Standards 2008 be amended to include the following, this will be the resulting entry for 1-naphthylacetic acid in Schedule One of the NZ (MRL) Food Standards 2008:

Amendment Rationale

The proposed MRL represents a new use pattern in New Zealand for the active ingredient 1-naphthylacetic acid. The proposed MRL will manage the new uses of 1-napthylacetic acid as a plant growth regulator on Satsuma and Encore mandarin varieties to the application rates and withholding periods that are approved good agricultural practice (GAP) in New Zealand (see below).

Chemical Information

Good Agricultural Practice

1-naphthylacetic acid is proposed for use as a fruit thinning agent for the Satsuma and Encore mandarin varieties. Application may be when fruitlets are between 10-12mm diameter, at a rate of 30gai/ha with a withholding period of: do not apply after fruitlets exceed 12mm diameter.

Residues Information

Residue data for Satsuma and Encore mandarin support a limit of quantification MRL of 0.01mg/kg at 130 days after the last treatment. An MRL of 0.01mg/kg is therefore proposed to support GAP.

Dietary Risk Assessment

The potential daily exposure via food (PDE_(food)) is used for dietary intake calculation where a value has been set. An appropriate acceptable daily intake (ADI) is used in the absence of a PDE_(food).

The chronic dietary exposure to 1-naphthylacetic acid is estimated by the National Estimated Dietary Intake (NEDI) calculation encompassing all registered uses of the chemical and food consumption data based upon the 1997 National Nutritional Survey for adults and the 1995 National Nutrition Survey of Australia, for children. The NEDI calculation is made in accordance with Guidelines for predicting dietary intake of pesticide residues (revised) [World Health Organization, 1997].

The NEDI for 1-naphthylacetic acid is equivalent to 0.09% of the ADI. It is therefore concluded that the chronic dietary exposure is small and the risk is acceptable.

Toxicological / Public Health Assessment

It has been determined that the use of 1-naphthylacetic acid as a plant growth regulator for use on Satsuma and Encore mandarins, according to the GAP specified above, is very unlikely to pose any health risks from consumption of the harvested commodity.

Other International MRLs

To meet New Zealand’s obligations under the Agreement on the Application of Sanitary and Phytosanitary Measures the proposed MRL will be notified to the World Trade Organization. Any country may choose to comment if they believe the proposed MRL represents a barrier to their trade.