Sheep, goats and pigs

Table 12. Residues of diazinon in the milk, fat or tissues of sheep, goats and pigs following spraying.

Country, ref.	Formulation. Application rate, ai	No. of sprays	Sample	Residues, mg/kg, at withdrawal interval
SHEEP
Australia Bull, 1971	EC	1		14 days (3 sheep)
	800 mg/l	jetting		Sheep		A	B		C	Mean
			Muscle			0.05	0.05		0.05	0.05
			Fat			0.15	0.08		0.06	0.13
	WP	1		Sheep		D	E		F	Mean
	800 mg/l	jetting	Muscle			0.03	0.06		0.09	0.06
				Control		0.06
			Fat			0.16	0.06		0,05	0.09
				Control		0.03
				Method 113 (sweep-codistillation; GLC thermionic).
				0.02 mg/kg limit of detection reported. Recoveries
				70% muscle, 92% fat at 0.2 and 0.5 mg/kg
				respectively. Results corrected.
Switzerland Morrison, 1994	EC 250	1	fat (tail base	Sheep no.				8		28 days
	600 mg/l	6 l/sheep	biopsy)					1 1.8		0.10
	(GAP)	(GAP=31)						2 1.6		0.11
								3 3.1		0.13
								4 3.3		0.17
								5 2.6		0.29
								6 3.5		0.11
				Mean				2.7±0.8		0.15±0.07
	EC A-139 F	1	same					1 2.2		0.14
	600 mg/l	6 l/sheep						2 2.4		0.17
	(GAP)							3 2.1		0.24
								4 0.78		0.15
								5 2,7		0.08
								6 3.2		0.16
				Mean				2.2±		0.16±0.05
	EC 600	1	same	Sheep no.				8		28 days
	600 mg/l	6 l/sheep		1				2.1		0.09
	(GAP)			2				2.1		0.06
				3				2.1		0.11
				4				2.0		0.22
				5				1.4		0.10
				6				1.9		0.14
				Mean				1.9±		0.12±0.12
				Method 24480.0. Mean recoveries from fat 95-100%
				on different days at 0.025 mg/kg. Reported LOD 0.005
				mg/kg; chromatograms suggest 0.01 mg/kg more practical.
GOATS
Australia Bull et al., 1986b	EC	1		1		3		7	14	21 days
	600 mg/l	5 l/goat	Muscle	0.14		0.03		0.01	<0.01	<0.01
	(GAP is 500	(GAP		0.06		0.04		0.02	<0.01	<0.01
	mg/l in	is 3 1)	Mean	0.1		0.04		0.02	<0.01	<0.01
	Australia, 600			Controls in all tissues <0.01 mg/kg
	mg/l in other			GAP pre-slaughter interval is 14 days.
	countries)			Two goats sampled at each time.
			Liver	0.04		<0.01		<0.01	<0.01	<0.01
				<0.01		<0.01		<0.01	<0.01	<0.01
			Mean	<0.03		<0.01		<0.01	<0.01	<0.01
			Kidney	0.08		<0.01		<0.01	<0.01	<0.01
				0.02		0.03		<0.01	<0.01	<0.01
			Mean	0.05		0.03		0.01	<0.01	<0.01
			Kidney fat	3.4		1.0		0.04	<0.01	<0.01
				1.1		1.4		0.22	0.02	<0.01
			Mean	2.3		1.2		0.13	<0.02	<0.01
			Omental fat	3.8		0.39		0.08	0.03	<0.01
				0.91		1.2		0.2	0.01	<0.01
			Mean	2.4		0.8		0.14	0,02	<0.01
Australia Strong et al., 1987	EC	1	Whole milk
	600 mg/l	5 l/goat	(5 goats)	Goat A		B	C		D	E		mean
			Pre-treatment	0.01		0.01	<0.01		0.01	0.01		<0.01
			Hours
			7	0.18		0,25	0.22		0.18	0.25		0.22
			24	0.07		0.08	0.09		0.06	0.03		0.07
			30	0.08		0.08	0.10		0.08	0.07		0.08
			48	0.03		0.03	0.04		0.02	0.02		0.03
			54	0.04		0.03	0.05		0.03	0.03		0.04
			72	0.01		0.01	0.02		0.01	0.01		0.01
			78	0.02		0.02	0.02		0.01	0.01		0.02
				Method 132A. 0.01 mg/kg limit of "detection"
				reported. Recovery 81% at 0.1 mg/1.
PIGS
Switzerland Formica, 1974b	EC 250 mg/l	1 5 l/pig	Muscle	1		3	7		14		28
				0.04		0.02	0.02		0.01		0.01
	(GAP)	(GAP is	Liver	All	<0.01
		1 l)	Kidney	All	<0.01
			Fat	0.22		0.05	0.02		<0.01		<0.01
			Skin	All	<0.01
		2	Muscle	0.02		0.01	<0.01		<0.01		<0.01
		(GAP is	Liver	All	<0.01
			Kidney	All	<0.01
		<3) 5 l/pig	Fat	0.15		0.06	<0.01		<0.01		<0.01
			Skin	0.05		0.02	<0.01		<0.01		<0.01
	EC	1	Muscle	0.08		0.04	0.01		0.02		0.04
	500 mg/l	5 l/pig	Liver	All	<0.01
			Kidney	0.01		<0.01	<0.01		<0.01		<0.01
			Fat	0.5		0.15	0.02		<0.01		<0.01
			Skin	0.13		0.02	<0.01		<0.01		<0.01
		2	Muscle	0.04		0.01	<0.01		<0.01		<0.01
		5 l/pig	Liver	All	<0.01
			Kidney	All	<0.01
			Fat	0.21		0.05	0.01		<0.01		<0.01
			Skin	0.01		0.01	<0.01		<0.01		<0.01
				Controls 0.01 mg/kg for all samples and times.
				Method REM 4/74. Recoveries 125, 75 and 90% at
				0.1 mg/kg from muscle, liver and fat respectively.
				0.01 mg/kg limit of "detection" reported. Results not corrected for recovery
				hydroxydiazinon
			Fat	<0.02 mg/kg in all but two samples (0.02 and 0.03 mg/kg) at 250 and 500 mg/l respectively).
			Other tissues	<0.02 mg/kg in all samples.
				pyrimidinol metabolite G 27 550
			Kidney	<0.1 mg/kg in all samples at 250 mg/l.
				<0.1, 0.12, 0.12, 0.14, 0.14, 0.16 at 500 mg/l.
			Other tissues	<0.1 mg/kg in all samples.
				diazoxon
			All tissues	<0.01 mg/kg in all samples

Sheep. Two studies were provided. In an Australian study sheep were treated once with a single jet spray with either a WP or an EC formulation, at 800 mg/l (twice the reported GAP concentration for Australia). Muscle and fat samples were analysed after slaughter 14 days later, the GAP interval (Bull, 1971). Although fat was identified as omental, subcutaneous and kidney fat, the data did not specify which residues were in which fat. The residues did not exceed 0.16 mg/kg in fat or 0.09 mg/kg in muscle. Details such as sample handling and storage conditions, intervals from sampling to analysis and confirmation of spray concentrations were not recorded, nor were sample chromatograms supplied.

A more recent and well documented Swiss study (Morrison, 1994) was reported to be in accordance with OECD GLP. Three groups of six sheep were sprayed with different EC formulations, all nominally at the Swiss GAP rate of 600 mg/l, actually 576-592 mg/l, and 6 l/animal (twice the GAP volume). Fat samples were taken by biopsy from the base of the tail 8 and 28 days later: the GAP slaughter interval is 21 days in Switzerland, 14 days in some other countries. Samples were stored at -20°C until analysis less than 6 months later. Blood samples were also taken.

Fat samples were extracted with acetonitrile, cleaned up on a solid-phase column and analysed by GLC with an NP detector. Recoveries were near 100% at 0.025 mg/kg. The reported limit of determination was 0.005 mg/kg, but 0.01 mg/kg appears to be more practical from the sample chromatograms.

Eight days after treatment diazinon residues in the fat ranged from 0.8 to 3.5 mg/kg with an overall mean of 2.3 mg/kg after 8 days and 0.06 to 0.3 mg/kg with a mean of 0.14 mg/kg after 28 days, with no significant difference between the three formulations.

Goats. Two Australian trials were reported. In one, each goat was treated once with 51 of an EC at 600 mg ai/l and 51 animal and the goats were slaughtered in pairs 1, 3, 7, 14 and 21 days after treatment (Bull et al., 1986b). GAP in Australia requires 500 mg/l and in other countries up to 600 mg/l. The higher residues of each pair one day after treatment were 0.14 mg/kg in muscle, 0.04 mg/kg in liver, 0.08 mg/kg in kidney, 3.4 mg/kg in kidney fat and 3.8 mg/kg in omental fat. After the Australian GAP slaughter interval of 14 days the only residues above 0.01 mg/kg were 0.02 mg/kg in one sample of kidney fat and 0.03 mg/kg in one of omental fat.

Samples were stored at -15°C until analysis by method 135 for which a limit of determination of 0.01 mg/kg was reported, although no sample chromatograms were presented. Recoveries were >87% at the lowest fortification level of 0.1 mg/kg. The interval from sampling to analysis was not reported, nor was confirmation of the actual spray concentration.

In the second study 5 goats were each sprayed once with 51 of EC at 600 mg/l (Strong et al., 1987). Diazinon residues were determined in the whole milk after 7 consecutive milkings by method 132A. Reported recoveries were 81% at 0.1 mg/kg but no sample chromatograms were presented. Samples were stored at -15°C until analysis, but the storage period was not reported nor was confirmation of the spray concentration. Residues decreased from a maximum of 0.25 and a mean of 0.22 mg/kg after 7 hours to 0.01-0.02 mg/kg after 72 and 78 hours. Withholding intervals for milk are 3 to 4 days in other countries.

Pigs. One old but relatively well documented Swiss study (Formica, 1974b) was reported. Pigs were each sprayed once or twice with 51 EC spray (11 is GAP) at either 250 or 500 mg ai/l, the GAP concentration in Switzerland and Egypt respectively. Samples of muscle, liver, kidney, skin and fat taken 1, 3, 7, 14 and 28 days after treatment were analysed for residues of diazinon, diazoxon, hydroxydiazinon and the pyrimidinol metabolite G27550. The Swiss GAP pre-slaughter interval is 21 days.

Although spray concentrations were not confirmed nor chromatograms provided, samples were stored at -20°C until analysis within 7 months of treatment. Residues of diazinon after 14 and 28 days were all <0.01 mg/kg except in two muscle samples with 0.02 and 0.04 mg/kg. Residues of hydroxydiazinon were <0.02 mg/kg in all samples except two of fat which contained 0.02 and 0.03 mg/kg. Residues of G 27550 were <0.1 mg/kg except in the kidneys of pigs treated at 500 mg ai/l, where they ranged from <0.1 to 0.16 mg/kg. No residues of diazoxon (<0.01 mg/kg) were detected in any sample.

Summary

For the convenience of a general picture, the residues resulting from treatments according to GAP shown in Tables 8 to 12 above are summarized in Table 13.

Table 13. Summary of diazinon residues found in milk and tissues of cattle, sheep, goats and pigs from treatments against ectoparasites according to GAP.

Sample Type of treatment			Diazinon, mg/kg, maximum and (median) residues in					Maximum residue, mg/kg, from any treatment
			Cattle	Sheep	Goats		Pigs
Milk		Ear tag	0.01 (0.01 mean) 0.3(0.2)fat					Milk 0.02 (mean)1
Dip				0.02(0.02)
Spray			0.05 (0.02 mean)		0.02
Muscle		Ear tag	0.02 (tongue)					Muscle 0.03
Dip				0.03(0.02)
Spray			0.032		<0.01(<0.01)		0.01
Liver		Ear tag	<0.01					Liver 0.032
Dip				0.01(<0.01)
Spray			0.032		<0.01(<0.01)		0.01
Kidney		Ear tag	<0.01					Kidney 0.032
Dip				0.02(0.02)
Spray			0.032		<0.01(0.01)		<0.01
Omental fat		Dip		1.3(1.1)				Omental fat 1.3
Spray			0.2(0.2)		0.03(<0.02)
Renal fat		Backrub	0.3(0.2)					Renal fat 0.7
Ear tag			0.04
Dip				0.7(0.7)
Spray			0.7(0.6) (low side)		0.02(<0.02)
Loin (= subcut?) fat		Backrub	0.7(0.2)					Loin fat (subcut.?) 0.7
Spray			0.08(0.05)
Subcut. fat		Ear tag	0.05 "back fat"					Subcutaneous fat 4.3
Dip				4.3(1.3)
Spray				0.3(0.14) (tail base fat)			<0.01 ("fat")
Max. mg/kg/matrix/animal
	milk		0.01	0.02	0.02		-
	muscle		0.03	0.03	<0.01		0.01
	liver		0.03	0.01	<0.01		<0.01
	kidney		0.03	0.02	<0.01		<0.01
	fat - >		0.7	4.3	0.03		<0.01

¹ Because milk is normally pooled, the highest mean, not the highest individual value, is recorded. This was 0.02 mg/kg from both spray and dip treatments.

² Estimated. There were no results at the GAP 3-day preestimate was made on the basis of the residues found at 1 and 7 days.-slaughter interval, so an