S.I. No. 124/1972:

ANIMAL AND POULTRY FEEDING STUFFS AND MINERAL MIXTURES (CONTROL OF ARSENIC) REGULATIONS, 1972.

ANIMAL AND POULTRY FEEDING STUFFS AND MINERAL MIXTURES (CONTROL OF ARSENIC) REGULATIONS, 1972.

I, JAMES GIBBONS, Minister for Agriculture and Fisheries, in exercise of the powers conferred on me by sections 6, 8 and 11 of the Fertilisers, Feeding Stuffs and Mineral Mixtures Act, 1955 (No. 8 of 1955), as adapted by the Agriculture (Alteration of Name of Department and Title of Minister) Order, 1965, ( S.I. No. 146 of 1965 ), hereby make the following regulations:

1. (1) These Regulations may be cited as the Animal and Poultry Feeding Stuffs and Mineral Mixtures (Control of Arsenic) Regulations, 1972.

(2) These Regulations shall come into force on the 1st day of June, 1972.

2. In these Regulations "feeding stuff", "compound feeding stuff" and "mineral mixture" have the meanings assigned to them respectively by section 1 of the Fertilisers, Feeding Stuffs and Mineral Mixtures Act, 1955 (No. 8 of 1955).

3. A person shall not use arsenic or any arsenical compound in the manufacture for sale of any feeding stuff, compound feeding stuff or mineral mixture.

4. A person shall not bring arsenic or any arsenical compound into any premises where any feeding stuff, compound feeding stuff or mineral mixture intended for sale is manufactured.

5. Where--

(a) a sample of a feeding stuff, compound feeding stuff or mineral mixture is taken pursuant to section 8 of the Fertilisers, Feeding Stuffs and Mineral Mixtures Act, 1955 (No. 8 of 1955), and in the manner prescribed under that Act, and

(b) the State Chemist or the Assistant State Chemist proposes to cause the sample to be analysed to ascertain whether arsenic or any arsenical compound has been used in the manufacture for sale of the feeding stuff, compound feeding stuff or mineral mixture, as the case may be, the sample shall be analysed by the Gutzeit Technique, namely:

(i) in case the sample does not contain antimony, in the manner specified in Part I of the Schedule to these Regulations, and

(ii) in case the sample contains antimony, in the manner specified in Part II of the said Schedule.

SCHEDULE

GUTZEIT TECHNIQUE

PART I

FOR SAMPLES NOT CONTAINING ANTIMONY

1. Apparatus

Gutzeit apparatus shall be prepared as follows:--

A wide-mouthed bottle (capacity 120 ml) is fitted with a rubber bung through which passes a glass tube 200 mm in length and of a diameter of 8 mm externally and 6.5 mm internally. The lower end of the glass tube is drawn out to 1 mm diameter and a hole about 2 mm diameter is blown in the side of the tube, near the constriction. The glass tube is lightly packed with cotton wool, previously moistened with 10 per cent lead acetate solution and dried, so that the cotton wool is not nearer than 25 mm from the top of the glass tube. The upper end of the glass tube is then pushed into the narrow end of a rubber bung (25 X 25 mm with a hole 6.5 mm diameter) so that the larger end of the rubber bung is flush with the end of the glass tube. A piece of mercuric chloride paper is placed flat on the top of the rubber bung. A similar bung is placed over the paper and secured by clips so that the two bungs meet to form a continuous tube. (The mercuric chloride paper is prepared by soaking smooth filter paper (at least 25 mm wide of a grade between 65--120 g/sq.m) in saturated mercuric chloride solution and then by drying at 60°C in the dark after pressing out the superfluous solution. The prepared paper should be stored in a dark place).

2. Reagents

Arsenic stock solution--Dissolve 0.132 g arsenic trioxide in 50 ml concentrated hydrochloric acid and dilute to 100 ml with water.

Dilute arsenic solution--Dilute as required 1 ml arsenic stock solution to 100 ml with water. (1 ml = 0.01 mg arsenic).

The following reagents shall be free of arsenic (As. T. grade):

Stannous chloride solution--Dissolve 33 g of stannous chloride in 10 ml of concentrated hydrochloric acid and dilute to 100 ml with water. Add 100 ml of concentrated hydrochloric acid, boil down to 100 ml and filter.

Stannated hydrochloric acid--Mix 1 ml of the stannous chloride solution with 100 ml of concentrated hydrochloric acid.

Bromine solution--Dissolve 30 g of bromine and 30 g of potassium bromide in water and make up to 100 ml.

Brominated hydrochloric acid--Mix 1 ml of the bromine solution with 100 ml concentrated hydrochloric acid.

Magnesium oxide--Magnesium nitrate slurry--Suspend 75 g of magnesium oxide and 150 g of magnesium nitrate in 1 litre of water. Agitate vigorously before adding to sample.

Potassium iodide.

Zinc, granulated.

3. Procedure.

Weigh a suitable quantity of the sample and mix thoroughly in an ashing dish with 10 ml of magnesium oxide--magnesium nitrate slurry. Dry at 100°C, ash at 550°--600°C, cool, moisten the residue with water, add 15 ml of hydrochloric acid (1:1), heat on a steam bath until ash dissolves, and filter.

Add a suitable volume of filtrate to the prepared bottle together with 10 ml stannated hydrochloric acid (or 15 ml brominated hydrochloric acid followed by removal of excess bromine with a few drops of stannous chloride). Add 1 g potassium iodide and 10 g zinc and immediately attach the prepared tube. Allow the reaction to proceed for 40 minutes (preferably at about 37°C) and compare the stain produced with those obtained using amounts of dilute arsenic solution ranging from 0.1--1.0 ml (0.001--0.01 mg arsenic).

4. A blank determination must be carried out with all arsenic determinations.

PART II

FOR FEEDING STUFFS CONTAINING ANTIMONY

5. Apparatus.

(a) Gutzeit apparatus prepared as described in Article 1 of this Schedule.

(b) A Kjeldahl flask (300 ml).

6. Reagents.

Reagents shall be free of arsenic (As. T. grade).

Ammonium oxalate solution, saturated.

Amyl alcohol.

Chloride-hydrazine-bromide--Mix together 100 g sodium chloride, 10 g hydrazine sulphate and 0.4 g potassium bromide.

Hydrochloric acid, concentrated.

Hydrochloric acid, stannated.

Hydrogen peroxide solution.

Nitric acid, concentrated.

Sodium sulphite.

Sulphuric acid, concentrated.

Zinc, granulated.

7. Procedure.

Wet oxidise a suitable quantity (e.g. 5 g) of the material in the Kjeldahl flask by first heating with 10 ml of concentrated nitric acid. When the initial vigorous reaction has ceased, cool, add 10 ml of concentrated sulphuric acid and continue the heating with further additions of nitric acid immediately the liquid begins to darken. Heat until white fumes appear and the liquid is colourless. If a pale yellow colour persists, heat the liquid further with a few drops of hydrogen peroxide solution (30 per cent by weight). Cool, add 15 ml of saturated ammonium oxalate solution and heat again until white fumes appear. Cool, add 7 ml of water, 5 g of the chloride-hydrazine-bromide mixture (avoiding contamination of the neck of the flask) and 10 ml of concentrated hydrochloric acid. Fit the condenser on to the flask immediately; and distill into an externally cooled mixture of 2 ml of concentrated nitric acid and 10 ml of water. The exit end of the condenser must dip below the surface of the liquid. Continue distilling until the liquid in the Kjeldahl flask is reduced to about half or until 5 minutes after the condenser is full of steam. Evaporate the distillate to dryness in a 100 ml beaker on the water bath and then evaporate twice more after the addition of 5 ml of water to remove the nitric acid. Dissolve the residue in 3 ml of concentrated sulphuric acid and dilute to 50 ml with water. Add 0.1 g of sodium sulphite and boil down to 25 ml to remove the sulphur dioxide. Add 8 ml stannated hydrochloric acid and make up to 60 ml with water. Transfer to the Gutzeit apparatus, add 10 g granulated zinc and 2 ml amyl alcohol. Connect up the glass tube fitted at the top of the apparatus with a mercuric chloride paper and allow the reaction to proceed at about 40°C for 40 minutes. Compare the stain obtained with standard stains produced by solutions of known concentrations of arsenic (0.001--0.01 mg arsenic), which have been submitted to the same process as the sample.

8. A blank determination must be carried out with all arsenic determinations.

GIVEN under my Official Seal, this 18th day of May, 1972.

JAMES GIBBONS,

Minister for Agriculture and Fisheries.

EXPLANATORY NOTE.

The Regulations prohibit the use of arsenic and arsenical compounds in the manufacture for sale of feeding stuffs, compound feeding stuffs and mineral mixtures. They also prohibit the bringing of arsenic and arsenical compounds into premises where feeding stuffs, compound feeding stuffs and mineral mixtures are manufactured for sale.