Background
Methods
Pesticide residue data analysis in tea
Tea consumption data
Relative potency factors
Transfer rate of pesticide residues to tea infusion
Modelling of cumulative dietary exposure
Compound | Variables | Definition | Assumption/distribution/formula | Source |
---|---|---|---|---|
OPs |
Conc
Qp
| Concentration in methamidophos equivalents of OPs in tea infusion (detected value) | Lognorm (0.052, 4.636)a | Monitoring data |
Lognorm (0.003, 0.041)b | ||||
Lognorm (0.003, 0.151)c | ||||
Conc
Qn
| Concentration in methamidophos equivalents of OPs in tea infusion (undetected value) | Uniform (0, 0.105)a | Monitoring data | |
Uniform (0, 0.044)b | ||||
Uniform (0, 0.105)c | ||||
Conc
*
Qp
| Concentrationin in methamidophos equivalents of OPs in tea infusion (detected value) | Lognorm (0.038, 2.987)a | Monitoring data | |
Lognorm (0.002, 0.019)b | ||||
Lognorm (0.001, 0.019)c | ||||
Conc
*
Qn
| Concentration in methamidophos equivalents of OPs in tea infusion (undetected value) | Uniform (0, 0.447)a | Monitoring data | |
Uniform (0, 0.235)b | ||||
Uniform (0, 0.447)c | ||||
Pp
| Rate of sample with detectable | 10.11%a | Calculated | |
13.53%b | ||||
6.20%c | ||||
Pn
| Rate of sample with undetectable | 89.89%a | Calculated | |
86.47%b | ||||
93.80%c | ||||
Conc
QC
| Concentration in methamidophos equivalents of OPs in tea infusion | Discrete (ConcQp: ConcQn, Pp: Pn) | Calculated | |
TR
| Transfer rate | 87.4% | Based on the open scientific literatures to calculate | |
22.1% | ||||
2.8% | ||||
Cons
| The consumption of tea | Invgauss (3.772, 0.721)a | China National Nutrient and Health Survey | |
Invgauss (4.474, 1.718)b | ||||
Invgauss (11.532, 10.870)c | ||||
BW
| Body weight for tea consumers | Normal (55.1, 15.5) | China National Nutrient and Health Survey |
Results
Residue and food consumption data
OPs | Samples analysed | Detected samples | Positive rate (%) | Concentrations of detected samples in tea (mg/kg) | |||||
---|---|---|---|---|---|---|---|---|---|
Mean | P50 | P95 | P97.5 | P99.9 | Max | ||||
Chlorpyrifos | 1660 | 112 | 6.75 | 0.138 | 0.060 | 0.594 | 0.788 | 1.900 | 1.900 |
Triazophos | 1619 | 42 | 2.59 | 0.152 | 0.125 | 0.427 | 0.801 | 0.830 | 0.830 |
Disulfoton | 1623 | 12 | 0.74 | 0.265 | 0.295 | 0.706 | 0.706 | 0.706 | 0.706 |
Dimethoate | 1642 | 11 | 0.67 | 0.261 | 0.220 | 0.980 | 0.980 | 0.980 | 0.980 |
Monocrotophos | 1634 | 10 | 0.61 | 0.201 | 0.095 | 0.909 | 0.909 | 0.909 | 0.909 |
Parathion-methyl | 1646 | 10 | 0.61 | 0.052 | 0.041 | 0.162 | 0.162 | 0.162 | 0.162 |
Ethion | 1638 | 9 | 0.55 | 0.066 | 0.020 | 0.240 | 0.240 | 0.240 | 0.240 |
Tolclofos-methyl | 386 | 2 | 0.52 | 0.080 | 0.080 | 0.080 | 0.080 | 0.080 | 0.080 |
Acephate | 1635 | 8 | 0.49 | 0.033 | 0.031 | 0.077 | 0.077 | 0.077 | 0.077 |
Methamidophos | 1640 | 8 | 0.49 | 0.057 | 0.033 | 0.120 | 0.120 | 0.120 | 0.120 |
Dichlorvos | 1638 | 7 | 0.43 | 0.055 | 0.014 | 0.130 | 0.130 | 0.130 | 0.130 |
Omethoate | 1628 | 6 | 0.37 | 0.068 | 0.070 | 0.930 | 0.930 | 0.930 | 0.930 |
Fenitrothion | 1638 | 6 | 0.37 | 0.033 | 0.016 | 0.100 | 0.100 | 0.100 | 0.100 |
Parathion | 1642 | 6 | 0.37 | 0.024 | 0.008 | 0.073 | 0.073 | 0.073 | 0.073 |
Phorate | 1649 | 6 | 0.36 | 0.006 | 0.003 | 0.017 | 0.017 | 0.017 | 0.017 |
Chlorpyrifos-methyl | 1598 | 5 | 0.31 | 0.020 | 0.005 | 0.080 | 0.080 | 0.080 | 0.080 |
Phosalone | 1616 | 5 | 0.31 | 0.047 | 0.025 | 0.152 | 0.152 | 0.152 | 0.152 |
Methidathion | 1629 | 5 | 0.31 | 0.076 | 0.044 | 0.170 | 0.170 | 0.170 | 0.170 |
Phosmet | 1575 | 3 | 0.19 | 0.013 | 0.013 | 0.013 | 0.013 | 0.013 | 0.013 |
Malathion | 1645 | 3 | 0.18 | 0.012 | 0.012 | 0.012 | 0.012 | 0.012 | 0.012 |
Pyridaphethione | 40 | 0 | 0 | – | – | – | – | – | – |
Diazinon | 6 | 0 | 0 | – | – | – | – | – | – |
Trichlorfon | 3 | 0 | 0 | – | – | – | – | – | – |
Quinalphos | 3 | 0 | 0 | – | – | – | – | – | – |
Phoxim | 3 | 0 | 0 | – | – | – | – | – | – |
Number of detected pesticides in samples | Non-fermented tea | Semi-fermented tea | Fermented tea |
---|---|---|---|
Number of detected samples | Number of detected samples | Number of detected samples | |
0 | 1031 | 230 | 257 |
1 | 84 | 33 | 12 |
2 | 21 | 1 | 5 |
3 | 4 | 1 | 0 |
4 | 2 | 0 | 0 |
≥ 5 | 5 | 1 | 0 |
Total of detected samples | 116 | 36 | 17 |
Total of number of samples | 1147 | 266 | 274 |
Tea category | Consumption of dry tea leaves (g/d) | |||||
---|---|---|---|---|---|---|
Mean | P50 | P90 | P95 | P97.5 | Max | |
Non-fermented green tea | 3.92 | 1.70 | 11.09 | 16.70 | 25.00 | 41.70 |
Partly fermented oolong tea | 4.42 | 3.40 | 9.98 | 10.00 | 10.00 | 10.00 |
Fermented black tea | 9.83 | 10.00 | 19.80 | 25.00 | 48.80 | 61.90 |
Dietary exposure assessment
Percentiles of exposure | OPsa (μg/kg bw/d) | OPsb (μg/kg bw/d) |
---|---|---|
Tea consumer | ||
Mean | 0.02 (0.02–0.02)c | 0.08 (0.08–0.09)c |
P50 | 0.01 (0.01–0.01) | 0.05 (0.05–0.05) |
P90 | 0.04 (0.04–0.06) | 0.17 (0.17–0.25) |
P95 | 0.06 (0.05–0.06) | 0.25 (0.24–0.25) |
P97.5 | 0.08 (0.07–0.08) | 0.33 (0.32–0.35) |
P99 | 0.11 (0.10–0.12) | 0.46 (0.44–0.50) |
P99.9 | 0.25 (0.20–0.30) | 1.08 (0.85–1.23) |