Residues resulting from supervised trials

Supervised field trials were carried out with granular formulations of aldicarb. The samples were mainly analysed by HPLC methods which determine aldicarb, its sulfoxide and sulfone individually. The limits of determination were typically around 0.01-0.02 mg/kg for each residue component. In some of the trials the residues were oxidized to the sulfone and determined by GLC with an FPD. The residues, expressed as aldicarb sulfone, are shown in the following Tables.

Bananas. Trials were conducted in Cameroon, Egypt, France (Martinique), and the Ivory Coast. Aldicarb was applied to the soil at the recommended maximum rate of 2 g ai/plant, corresponding to 3.6-4 kg ai/ha. Samples were taken from 3 to >360 days after the last application. The residues were determined in composite samples consisting of 7-12 fingers, or in individual fingers. In some experiments the peel and pulp were analysed separately. The results are summarized in Table 1.

Potatoes. The reported supervised trials represented a wide geographical distribution and covered a period of 15 years. The samples were analysed either by GLC or HPLC methods based on the principles described in the 1994 evaluation. The major residue component was aldicarb sulfoxide.

Supervised trials were carried out in Argentina, Belgium, Canada, Czechoslovakia, Ecuador, Germany, Greece, Hungary, Italy, Netherlands, Spain, and the UK between 1978 and 1992. The trial conditions reported and the residues detected in composite samples are summarized in Table 2. In addition, a number of "commercial trials" were reported from South Africa in a summarized form without details of the trial conditions, the actual dosage rates or the analytical methods. The data from the trials are also given in Table 2, but are distinguished from the fully reported trials by shading.

Table 1. Aldicarb residues¹ in bananas from supervised trials.

Country, Location, Year	Variety	Application		PHI, days	Portion of commodity analyzed	Residues mg/kg			Ref.
		No., Form.	Rate, ai, kg/ha &/or g/plant			Mean	Min.	Max.
Cameroon Nyombe, 1992	Grand Naine		3.6	33	Whole fruit2	0.11	0.05	0.20	JM27
			2 g/plant	63		0.23	0.09	0.41
				92		0.11	0.04	0.19
				124		0.04	0.02	0.08
Cameroon Penja, 1993	Grand Naine		3.6	114	Whole fruit2	0.02	0.02	0.03	JM28
			2 g/plant
Egypt, Menoufia 1992	Balika		2 g/plant	87	Whole fruit2	0.02	0.02	0.03	JM29
			2.55 g/plant	154	Whole fruit2	0.02	0.02	0.02
France (Martinique) Danoux, 1991	Poyo	3	2 g/plant	119	Pulp of mature yellow fruit	0.04			JM30
Barriere 1991	Grand Naine	3		175-205	Pulp of mature yellow fruit	0.01
Moulin a vent, 1991	Grand Naine	2		148-175	Pulp of mature yellow fruit	0.04
Camille 1990	Grand Naine	2		>360	Pulp of mature yellow fruit	0.02
Daroux 1991	Grand Naine	2		85-114	Pulp of mature yellow fruit	0.02
Mangot 1991		3		175-205	Pulp of mature yellow fruit	0.025
Cloture 199)	Grand Naine	2		175-205	Pulp of mature yellow fruit	0.02
La Pointe 1991	Poyo	2		85-114	Pulp of mature yellow fruit	0.025
Sapotille 1991	Grand Naine	3		146-173	Pulp of mature yellow fruit	0.01
Ravine 1991	Poyo	1		85-114	Pulp of mature yellow fruit	0.06
Terre Grasse 1991	Grand Naine	1		119	Pulp of mature yellow fruit2	0.13
Etuve 1991	Grand Naine	1		85-114	Pulp of mature yellow fruit2	0.10
Savane 1991	Grand Naine	1	2 g/plant	94	Pulp of mature yellow fruit	0.01
CAF9 1991	Grand Naine	1		55-85	Pulp of mature yellow fruit	0.05
Papaye 1991	Poyo	1		113-143	Pulp of mature yellow fruit	0.04
Fefe 1991	Grand Naine	1		122	Pulp of mature yellow fruit	0.01
Dinde 1991	Grand Naine	1		151	Pulp of mature yellow fruit	0.03
Beauvallon 1991	Grand Naine	3		88	Pulp of mature yellow fruit	0.29
Neuf Chateau 1991	Grand Naine	4		86-89	Pulp of mature yellow fruit	0.12
Lamberty 1991	Grand Naine	1		167	Pulp of mature yellow fruit	0.03
La Rose 1991	Grand Naine	1		126	Pulp of mature yellow fruit2	0.09	0.05	0.18
Mapoue 1991	Poyo	2		114-144	Pulp of mature yellow fruit2	0.07	0.02	0.18
Carangaise 1991	Poyo/G. N	2		94	Pulp of mature yellow fruit2	0.15	0.03	0.25
France/ Guadeloupe 1991	Grand Naine	1	2 g/plant	100	Pulp of mature green fruit2	0.172	0.04	0.75	JM31
Martinique 1993	Grand Naine	1	2 g/plant	89	Pulp of mature green fruit2	0.39	0.08	0.81
Martinique 1987		1	2 g/plant	3	Whole fruit3	0.015			JM32
					Pulp	0.012	0.01	0.02
				7	Whole fruit3	0.067
					Pulp	0.056	0.02	0.09
				14	Whole fruit3	0.21
					Pulp	0.20	0.09	0.41
				30	Whole fruit3	0.20
					Pulp	0.16	0.04	0.29
				45	Whole fruit3	0.35
					Pulp	0.28	0.02	0.53
				60	Whole fruit3	0.50
					Pulp	0.45	0.23	0.70
				75	Whole fruit3	0.23
					Pulp	0.18	0.05	0.38
				90	Whole fruit3	0.31
					Pulp	0.26	0.12	0.38
				120	Whole fruit3	0.077
					Pulp	0.071	0.01	0.11
				150	Whole fruit3	0.037
					Pulp	0.035	0.01	0.11
Grand Reduit 1988	Grand Naine	3	2 g/plant	19	Green fruit4, whole	0.11			JM33
					Peel	0.11
					Pulp	0.07
				19	Yellow fruit, whole	0.11
					Peel	0.15
					Pulp	0.085
Moulin l'Etang 1988	Grand Naine	3	2 g/plant	93	Green fruit4, whole	0.04
					Peel	0.06
					Pulp	0.04
				103	Yellow fruit, whole	0.13
					Peel	0.20
					Pulp	0,08
Union II 1989	Grand Naine	5G	2 g/plant	27	Pulp of mature fruit	<0.11	0.02	0.23	JM34
				59		<0.06	<0.02	0.09
				87		<0.04	<0.02	0.08
		10G	2 g/plant	27	Pulp of mature fruit	<0.09	<0.03	0.13
				59		0.05	<0.03	0.06
				87		<0.03	<0.02	0.03
		15G	2 g/plant	27	Pulp of mature fruit	0.06	0.04	0.09
				59		<0.05	0.02	0.07
				87		<0.03	<0.02	0.05
Gradis 1989	Poyo	1	2 g/plant	27	Pulp of mature fruit	0.18	0.06	0.28
		5G		60		0.20	0.14	0.30
				88		0.18	0.11	0.34
		10G	2 g/plant	27	Pulp of mature fruit	0.17	0.12	0.26
				60		0.39	0.14	0.65
				88		0.19	0.08	0.32
		15G	2 g/plant	27	Pulp of mature fruit	0.26	0.05	0.83
				60		0.17	0.12	0.23
				88		0.16	0.09	0.29
Ressource 1989	Grand Naine	1	2 g/plant	27	Pulp of mature fruit	0.11	0.04	0.20
		5G		81		0.13	0.07	0.27
				88		0.23	0.16	0.3
		10G	2 g/plant	27	Pulp of mature fruit	0.18	0.11	0.36
				81		0.23	0.19	0.39
				88		0.18	0.15	0.27
		15G	2 g/plant	27	Pulp of mature fruit	0.43	0.27	0.98
				81		<0.23	0.02	0.55
				88		0.19	0.07	0.29
Ivory Coast Azaguie, 1992		1	4.0	31	Whole fruit2	0.16	0.05	0.28	JM35
			ca. 2.0	60		0.28	0.08	0.48
			g/plant	90		0.40	0.06	0.82
				122		0.23	0.06	0.47
Thomasset 1993		1	4.0	92	Whole fruit2	0.23	0.14	0.33	JM36
			ca. 2.0 g/mat	120		0.17	0.08	0.28
Bamacomoe 1993	Grand Naine		4.0	94	Whole fruit2	0.20	0.05	0.31
			ca. 2.0 g/plant	123		0.07	0.05	0.10
			3.6 ca. 2 g/plant	>90	Whole fruit2	0.07	0.02	0.12	JM37
Damotte	Grand Naine		4.0 ca. 2 g/plant	>90	Whole fruit	0.036			JM38
			4.0 ca. 2 g/plant	>90	Whole fruit	0.032

¹ Residues of aldicarb its sulfoxide and sulfone were either measured and reported individually or determined as sulfone after oxidation. In the Table the residues are expressed as aldicarb sulfone.

² Individual fingers were analyzed.

³ Samples were taken from the upper and lower parts of the bunch. At each PHI the pulp and peel of 10 fruits were analyzed separately.

Whole fruit: residues in the peel and pulp of individual fingers were determined separately, but only the mean values of residues found in 10 fingers were reported.

Pulp: reported as the mean value and range of residues in the pulp of individual fingers.

⁴ Results for mature green and yellow fruits are each based on 2 individual samples. Shipment of fruit lasted approximately 13 days; an additional 6 days was allowed for ripening to the yellow fruit stage.

Table 2. Aldicarb residues¹ in composite potato samples from supervised trials. All single applications except where otherwise shown.

Table 2. Aldicarb residues¹ in composite potato samples from supervised trials. All single applications except where otherwise shown. (a)

Table 2. Aldicarb residues¹ in composite potato samples from supervised trials. All single applications except where otherwise shown. (b)

Table 2. Aldicarb residues¹ in composite potato samples from supervised trials. All single applications except where otherwise shown. (c)

Table 2. Aldicarb residues¹ in composite potato samples from supervised trials. All single applications except where otherwise shown. (d)

Table 2. Aldicarb residues¹ in composite potato samples from supervised trials. All single applications except where otherwise shown. (e)

Table 2. Aldicarb residues¹ in composite potato samples from supervised trials. All single applications except where otherwise shown. (f)

Table 2. Aldicarb residues¹ in composite potato samples from supervised trials. All single applications except where otherwise shown. (g)

¹ Residues expressed as aldicarb sulfone
² B.: broadcast application. F.: in furrow application. S.: side band or side dress application.
³ No GAP PHI, tubers were ready for marketing at new potato stage

Many studies have been conducted to determine the level of residues in potatoes in the USA. and the UK during 1990-1993. In these trials large number of individual potato tubers taken from single sites were analysed in order to obtain information on the within-field and the field-to-field variation of residues, depending on the mode of application, method of irrigation and climatic conditions. The trial conditions, numbers of tubers analysed and the sum of the carbamate residues expressed as aldicarb sulfone are given in Table 3. The residues deriving from trials according to the different use patterns established for the Northwest States and for Florida are underlined. In estimating maximum residue levels the growing and climatic conditions of the Northern States (Washington, Idaho, Oregon, Michigan, North Dakota, Pennsylvania and Maine) and the Southern States (Florida, Texas) of the USA were considered to be comparable.

The many residues measured in individual tubers provide an excellent basis for the precise estimation of acute dietary risk deriving from the use of the compound. However, since the range of residues in individual tubers is much wider than the range of average residues in composite samples consisting of 10-12 tubers, the results cannot be used directly for estimating maximum residue levels. Therefore composite random samples consisting of 12 tubers, the recommended sample size according to FAO Guidelines (FAO, 1990), were drawn with replacement from some of the primary residue data sets obtained from individual tubers according to a computer programme described recently (Ambrus, 1996). The programme draws the composite samples and calculates their average residues from the residue content of the potatoes selected for each sample. Figures 1-6 show the relative frequency distribution of residues in individual potatoes and in composite samples. It can be seen that the distributions of the residues in the primary samples are far from normal, so distribution-free statistics have to be used for their analysis. In such cases a minimum of 90 samples are required to estimate the 95th percentile of the population with 99% confidence (FAO, 1993). Composite samples were therefore drawn from primary sample populations taken from uniformly treated areas (excluding the end sections of rows) and consisted of at least 100 samples with one exception where there were 79 samples. The means, medians, and minimum and maximum residues found in 100 replicate composite samples are also presented in Table 3 together with the corresponding primary residue data. Since the average residues in composite samples are used to determine whether the crop had been treated according to GAP, the maximum residues found in composite random samples drawn by the computer are underlined in the Table.

Six field trials were conducted in different locations of the UK at recommended and double rates. Fifty individual tubers were collected from each site and analysed for aldicarb residues (Maycey et al., 1991; Brockelsby et al., 1991). The average residues ranged from 0.14 to 0.46 mg/kg following applications according to GAP.

Table 3. Aldicarb residues¹ in individual potato tubers deriving from supervised trials. All single applications.

Table 3. Aldicarb residues¹ in individual potato tubers deriving from supervised trials. All single applications. (a)

Table 3. Aldicarb residues¹ in individual potato tubers deriving from supervised trials. All single applications. (b)

Table 3. Aldicarb residues¹ in individual potato tubers deriving from supervised trials. All single applications. (c)

Table 3. Aldicarb residues¹ in individual potato tubers deriving from supervised trials. All single applications. (d)

Table 3. Aldicarb residues¹ in individual potato tubers deriving from supervised trials. All single applications. (e)

¹ Expressed as aldicarb sulfone (aldicarb residues mg/kg = aldicarb sulfone mg/kg x 0.856)

² States of the USA: WA Washington; ID Idaho; CO Colorado; NE Nebraska; FL Florida; MN Minesota; OR Oregon; MT Montana; MI Michigan; CA California; ND North Dakota; TX Texas; ME Maine; PA Pennsylvania.

³ B broadcast application; Be broadcast at emergence; BR band over row application at emergence; F in furrow application; GFA gravity-flow application; PDA positive-displacement application; f.i. furrow irrigation; o.i. overhead irrigation

⁴ Samples were taken from the centre of the row

⁵ Samples were taken from the end of the row

Nineteen field trials were conducted in the Pacific Northwest region of the USA to determine whether irrigation methods affected the magnitude of aldicarb residues in potatoes treated with a 15G formulation (Tew, 1992). Overhead and in-furrow irrigation methods were compared. All plots were treated with the nominal maximum label rate of 3.36 kg ai/ha with commercial ground equipment. Plots irrigated in-furrow were treated at planting, while overhead irrigation was either at planting or at emergence. A total of 340 tubers from plots irrigated in-furrow and 824 tubers from plots treated by overhead irrigation plots were analysed.

Figure 1. Relative frequency distribution of aldicarb sulfone residues in potato samples from trial 90-129.

Notes:
Primary samples:
Mean = 0.295 Standard Deviation = 0.1820 Median = 0,255
Composite samples:
Mean = 0.294 Standard Deviation = 0.04989 Median = 0.2875

Figure 2. Relative frequency distribution of aldicarb sulfone residues in potato samples from trial 90-138.

Notes:
Primary samples:
Mean = 0.0773 Standard Deviation = 0.0724723 Median = 0.06
Composite samples:
Mean = 0.077 Standard Deviation ⁼ 0.0200693 Median = 0.076

Figure 3. Relative frequency distribution of aldicarb sulfone residues in potato samples from trial 90-142.

Notes:
Primary samples
Mean = 0.166 Standard Deviation = 0.10245 Median = 0.15
Composite samples
Mean = 0.163 Standard Deviation = 0.02897 Median = 0.160

Figure 4. Relative frequency distribution of aldicarb sulfone residues in potato samples from trial 90-152.

Notes:
Primary samples:
Mean = 0.0306 Standard Deviation = 0.04690 Median = 0.01
Composite samples:
Mean = 0.0311 Standard Deviation = 0.01242 Median = 0.0275

Figure 5. Relative frequency distribution of aldicarb sulfone residues in potato samples from several fields after harvest.

Notes:
Primary samples:
Mean = 0.454 Standard Deviation = 1.0590 Median = 0.12
Composite samples:
Mean = 0.4576 Standard Deviation = 0.31584 Median = 0.371
Residues between 9.1 and 10.2 mg/kg level at 1% relative frequency are not shown

Figure 6. Relative frequency distribution of aldicarb sulfone residues in potato samples after 6 months storage.

Primary samples:
Mean = 0.301 Standard Deviation = 0.4347 Median = 0.125
Composite samples:
Mean = 0,302 Standard Deviation = 0.1108 Median = 0.2788

In the in-furrow irrigation trials the maximum residue (aldicarb plus its metabolites) was 5.30 mg/kg, and eight tubers contained residues above 1 mg/kg.

Following treatments at planting and at plant emergence with overhead irrigation, the maximum residues found were 0.49 and 0.74 mg/kg respectively, and 95% of the tubers contained residues below 0.15 and 0.3 mg/kg respectively. The average residues ranged from 0.03 to 0.3 mg/kg in both primary and composite samples. At 155 and 159 days PHI the maximum residues found in composite samples deriving from two trials were 0.15 mg/kg and 0.13 mg/kg, respectively.

Seventeen field trials were conducted in twelve States of the USA in which aldicarb was applied in-furrow at planting at a target rate of 3.36 kg ai/ha (Tew, 1993a). Treated plots were subdivided into three sections at the time of sampling. The first and last 1.5 m sections of each row were marked and identified as row-end sections. The remaining centre parts of the plots were considered as the uniform application area (row centre). Samples were collected separately from the row centre and the row-end sections. In one trial (92-130) PDA equipment was used, while in the other trials the treatment was carried out by gravity-flow application (GFA). A total of 918 individual potato tubers were analysed. Of these, twelve contained total aldicarb residues above 1 mg/kg, and all of these samples were taken from row-end sections. The maximum residue found was 3.13 mg/kg. The maximum residue found in any row-centre sample was 0.91 mg/kg. The 95th percentile for all samples was 0.40 mg/kg, for row-end samples 0.52 mg/kg, and for row-centre samples 0.34 mg/kg. Since 24-30 potatoes were analysed from each sections, the residues in composite samples were not calculated.

Eight field trials in six States of the USA were designed to determine the variability of aldicarb residues within treated plots and within individual plants (Tew, 1993b). The pesticide was applied at the maximum nominal recommended rate in furrow at planting or with a granular spreader at emergence. One hundred individual potato tubers were analysed from each plot, except in trial 90-129 from which 300 tubers were analysed. Of the total of 1621 samples analysed, only two tubers contained residues above 1 mg/kg, the maximum residue found was 1.3 mg/kg. At PHIs corresponding to GAP the average residues ranged from 0.02 mg/kg to 0.09 mg/kg and the maximum residues in composite samples were between 0.03 and 0.15 mg/kg (Table 3).

Ten potato plants were randomly selected from each plot. All of the tubers found under the selected plants were analysed individually. The coefficient of variation of residues in the tubers from one plant ranged from 0% (three plants) to 350% (one plant), but some of these results are biased by the very low residue levels and few (4-6) tubers per plant. The average residues and their relative standard deviations (coefficients of variation) are shown in Table 4.

Sixteen trials were conducted in four States of the USA to compare the variability and magnitude of the residues in potato tubers grown in the 6 m end-sections of rows, where the tractor comes to a stop before the applicator is lifted, with the mid-row variability and residue levels (Tew, 1994a). Positive-displacement application (PDA) equipment and the conventional gravity-flow applicator (GFA) were used on the side-by-side test plots in each trial. The number of samples analysed from the end-row sections varied from 75 to 101. Thirty tubers were analysed from the mid-row section. A total of 3414 individual potato tubers from the treated plots were analysed. The results are summarized in Table 3.

From the PDA-treated plots a total of 1529 end-row tubers were analysed, of which three contained residues above 1 mg/kg (1.2, 1.2, and 1.12 mg/kg). The highest residues found in mid-row samples were 0.61, 0.51 and 0.32 mg/kg. The average residues in mid-row and end-row samples from treatments complying with GAP ranged from <0.02 to 0.18 mg/kg and from <0.02 to 0.23 mg/kg respectively.

A total of 1525 individual tubers were analysed from end-row sections following GFA treatment. Of these 67 tubers contained residues over 1 mg/kg with a maximum value of 12.8 mg/kg. The average residues in end-row samples ranged from 0.03 to 0.79 mg/kg.

The Meeting examined the relationship between the average and maximum residues detected in individual potato tubers at sites treated according to the GAP rate and PHI, taking into consideration all middle and end-row ground applications, representing most of the world-wide conditions of use, where the number of potato tubers was above 80 (in most cases it was 100). The selected primary sample populations cover about 95% of residues with 98-99% confidence, which provides a valid data base for estimating the ratio of maximum to average residues. The data are shown graphically in Figure 7. The linear regression of the data resulted in a regression coefficient of 0.904 which indicates an acceptable correlation.

Figure 7. Relation between maximum and average residues from trials according to GAP, including end-row samples.

Table 4. Average numbers of tubers found under one plant, and the average residues and their coefficients of variation in single potato tubers under individual plants and within experimental plots.

Trial No.	Within-plant			Within-plot
	Mean no. of tubers	Mean residue, mg/kg	CV %	Residue, mg/kg	CV %
90-026	6	0.12	24	0.085	88.8
90-095	8	0.1	46	0.089	67.2
90-096	8	0.06	27	0.05	81.9
90-107	7	0.09	37	0.14	51.7
90-129	11	0.24	55	0.295	65.7
90-130	14	0.06	51	0.057	57.4
90-146	8	0.06	109	0.019	31.7
90-191				0.046	40.9
Grand average		0.104	49.9	0.098	60.7
Between-plot CV					87.4

The within-field variation of composite potato samples taken between 118 and 155 days after treatment (Table 5) gave an average CV of 23% and an average variance (square of standard deviations) of 0.0002. The field-to-field variation of the average residues in different regions following GAP applications (Table 6) gave CVs ranging from 70% to 139% with an average of 102%. The average variance for centre-row samples from GAP treatments was 0.0105. The total variance of residues in the samples (V_s) is the sum of the within-field (V_wf) and between-field (V_bf) variances:

V_s = V_bf + V_wf

Since the average within-field variation is only 2-40% of the between-field variation, it effectively does not influence the total variance of the residues and the average residues obtained by the analyses of >12 individual potato samples can be used to estimate the maximum residue levels reflecting GAP.

Table 5. Variation of aldicarb residues in composite and primary samples arising soil treatment with aldicarb

Trial No.	Composite samples							Primary samples CV
	Residues expressed as sulfone, mg/kg				SD	Variance	CV
	Mean	Median	Minimum	Maximum
90-026	0.083	0.080	0.050	0.150	0.0184	0.00034	0.22.	0.89
90-096	0.056	0.051	0.034	0.099	0.0137	0.00019	0.24	0.82
90-137	0.073	0.070	0.044	0.132	0.0166	0.00028	0.23	0.82
90-138	0.077	0.076	0.038	0.148	0.0202	0.00041	0.26	0.94
90-146	0.022	0.022	0.020	0.030	0.0023	0.00001	0.10	0.32
90-151	0.048	0.045	0.021	0.099	0.0151	0.00023	0.31	1.12
90-152	0.031	0.028	0.011	0.063	0.0125	0.00016	0.40	1.53
90-191	0.045	0.043	0.038	0.059	0.0050	0.00003	0.11	0.41
Average	0.054					0.00021	0.23	0.86
Between-field SD: 0.0221			Between-field variance: 0.000488
Between-field CV: 0.405			Within-field average CV: 0.23

Table 6. Distribution of average residues in potatoes expressed as aldicarb sulfone measured at experimental field sites.

Type of application	Residue as aldicarb sulfone, mg/kg				Variance	CV %
	Mean	Median	Minimum	Maximum
Treatment according to US N.W. GAP	0.046	0.04	0.004	0.14	0.00114	73.1
Treatment according to US Florida GAP	0.11	0.075	0.061	0.21	0.003588	54.3
Treatment according to GAP other than USA & South Africa	0.071	0.03	0.005	0.7	0.0103	143.2
Treatment according to GAP other than USA	0.101	0.03	0.005	1.14	0.0299	170.9
All GAP samples	0.099	0.04			average: 0.0105	average: 99.4
Non-GAP applications
US N.W., PHI 100-135 days	0.148	0.09	0.01	0.9	0.0369	130
US row-end samples, PHI around 150 days	0.10	0.038	0.005	0.69	0.0293	171
US row-end samples, PHI around 100 days	0.176	0.125	0.025	0.5	0.0247	89