Dissipation of chlorpyrifos in apples under storage conditions in Kashmir Valley

Figures & data

Figure 1. Chemical structure of chlorpyrifos.

Figure 2. Six-point calibration curve (10 ppb to 200 ppb (μg/ml)).

Table 1. Recovery percentage of chlorpyrifos from Golden Delicious apple fruits

Fortification levels (μg/kg)	Replicate recovery (%) ±SD	Average recovery (%) ±SD^a	%Relative standard deviation
20	83.45 82.46 84.5	83.47 ± 1.02	1.22
50	81.60 82.3 80.4	81.43 ± 0.96	1.18
100	92.43 91.2 92.3	91.97 ± 0.67	0.73
200	85.65 85.4 84.3	85.1 ± 0.71	0.84

Figure 3. Chromatogram of chlorpyrifos: (i) Blank, (ii) standard, and (iii) samples.

(x) Chromatogram for dose T3 at 6 months. (y) Chromatogram for dose T2 at 6 months. (z) Chromatogram for dose T1 at 6 months.

Figure 3. (Continued).

Table 2. Dissipation trend in chlorpyrifos in Golden Delicious apples

Chlorpyrifos dissipation for dose T1 following Ct = Coe−kt
Ct (days)	k	t	ci	Ln ci	Ln ct	Final values	Real lab values (µg/kg)	Percentage decrease
0	0.115	0	40.62	3.70	3.70	40.62	40.62	0
60	0.115	60	40.62	3.70	3.01	20.37	20.61	49.26%
120	0.115	120	20.37	3.01	1.63	5.12	10.155	75.00%
180	0.115	180	5.12	3.01	−0.43	0.64	5.077	87.50%
240	0.115	240	0.64	−0.44	−3.20	0.040	2.53	93.77%
300	0.115	300	0.04	−3.21	−6.66	0.001	ND	ND
Half-life, t^1/2: 59.92 (days)
Mean lifetime, τ: 86.45 (days)
Decay constant, λ: 0.011(days)
MRL: 0.5 mg/kg
Waiting period: 1.6 (days)
Correlation coefficient: 0.84

Figure 4. (a) Graph of residue dissipation vs. time following first-order kinetics for dose T1. (b) Graph of residue dissipation vs. time following first-order kinetics for dose T2. (c) Graph of residue dissipation vs. time following first-order kinetics for dose T3.

Table 3. Dissipation trend in chlorpyrifos in Golden Delicious apples

Chlorpyrifos dissipation for dose T2 following Ct = Coe−kt
ct (days)	K	T	ci	Lnci	Ln ct	Final concentration	Real lab values (µg/kg)	Percentage decrease
0	0.115	0	37.2	3.61	3.61	37.23	37.23	0
60	0.0115	60	37.2	3.61	2.92	18.67	18.67	49.85%
120	0.0115	120	18.6	2.92	1.54	4.69	9.3	50.19%
180	0.0115	180	4.69	1.54	−0.52	0.591	4.65	50.19%
240	0.0115	240	0.59	−0.52	−3.28	0.037	2.32	50.53%
300	0.0115	300	0.03	−3.29	−6.74	0.00117	ND	99.90%
Half-life, t^1/2: 59.93 (days)
Mean lifetime, τ: 86.46 (days)
Decay constant, λ: 0.011(days)
MRL: 0.5 mg/kg
Waiting period: 1.58 (days)
Correlation coefficient: 0.83

Table 4. Dissipation trend in chlorpyrifos in Golden Delicious apples

Chlorpyrifos dissipation for dose T3 following Ct = Coe−kt
ct (days)	K	t	ci	lnci	Ln ct	Final concentration	Real lab values (µg/kg)	Percentage decrease
0	0.11	0	35.27	3.56	3.563	35.27	35.27	0
60	0.01	60	35.27	3.56	2.87	17.69	17.635	50.01%
120	0.01	120	17.69	2.873	1.493	4.45	8.81	50.02%
180	0.01	180	4.45	1.492	−0.57	0.56	4.4	50.05%
240	0.01	240	0.56	−0.57	−3.33	0.035	2.2	50.05%
300	0.01	300	0.035	−3.35	−6.80	0.0011	0	99.90%
Half-life, t^1/2: 59.95 (days)
Mean lifetime, τ: 86.499 (days)
Decay constant, λ: 0.011(days)
MRL: 0.5 mg/kg
Waiting period: 1.55 (days)
Correlation coefficient: 0.838

Table 5. Risk assessment for chlorpyrifos dose T1

Time (days)	Pesticide ADI (mg/kg)	Average weight of person (kg)	MPI (mg/kg/ person/day)	Average residue (µg/kg)	Average consumption (kg)	TMRC (µg/kg)
0	0.01	55	0.55	40.62	0.08	3.2496
60	0.01	55	0.55	20.61	0.08	1.6488
120	0.01	55	0.55	10.155	0.08	0.8124
180	0.01	55	0.55	5.077	0.08	0.40616
240	0.01	55	0.55	2.53	0.08	0.2024
300	0.01	55	0.55	0	0.08	0

Table 6. Risk assessment for chlorpyrifos dose T2

Time (days)	Pesticide ADI (mg/kg)	Average weight of person (kg)	MPI (mg/kg/person/day)	Average residue (mg/kg)	Average consumption (kg)	TMRC (µg/kg)
0	0.01	55	0.55	37.23	0.08	2.9784
60	0.01	55	0.55	18.67	0.08	1.4936
120	0.01	55	0.55	9.3	0.08	0.744
180	0.01	55	0.55	4.65	0.08	0.372
240	0.01	55	0.55	2.32	0.08	0.1856
300	0.01	55	0.55	0	0.08	0

Table 7. Risk assessment for chlorpyrifos dose T3

Time (days)	Pesticide ADI (mg/kg)	Average weight of person (kg)	MPI (mg/kg/person/day)	Average residue (mg/kg)	Average consumption (kg)	TMRC (µg/kg)
0	0.01	55	0.55	35.27	0.08	2.8216
60	0.01	55	0.55	17.635	0.08	1.4108
120	0.01	55	0.55	8.81	0.08	0.7048
180	0.01	55	0.55	4.4	0.08	0.352
240	0.01	55	0.55	2.2	0.08	0.176
300	0.01	55	0.55	0	0.08	0