Fig. 1:
Fig. 2:
Fig. 3:
Fig. 4:
Fig. 5:
Comparison of trace element concentration (μg kg-1) in different countries of walnut origin_
| Location | Sampling site | Cr | Ni | Cd | Pb | References |
|---|---|---|---|---|---|---|
| Türkiye | Production areas | 474.9 | 202.8 | 2.1 | 30.6 | Present study |
| Sweden | Supermarket | 1.3 | 1.6 | 0.6 | 0.2 | (Rodushkin et al., 2008) |
| Brazil | Supermarket | / | / | <2.0 | <6.0 | (Muller et al., 2012) |
| Bulgaria | Growing area | / | / | 15.9 | 61.3 | (Arpadjan et al., 2013) |
| Chile | Supermarket | 82.4 | 719.0 | 1.3 | 9.2 | (Kafaoğlu et al., 2014) |
| Türkiye | Near highway area | 503.0 | 1160.0 | 55.0 | / | (Kalkışım et al., 2014) |
| China | Supermarket | <0.9 | / | 20 | <11 | (Yin et al., 2015) |
| Serbia | Supermarket | 1423.7 | 969.7 | ND | ND | (Tosic et al., 2015) |
| China | Farmer’s markets | 290.0 | / | 16.0 | 6.9 | (Ni et al., 2016) |
| Spain | Supermarket | 1454 | 1727 | 705 | <0.8 | (Moreda-Pineiro et al., 2016) |
| China | Production areas | 184.1 | / | 7.3 | 55.6 | (Han et al., 2018) |
| China | Production areas | 400.0 | 1600.0 | 3.0 | 30.0 | (Wu et al., 2020) |
| Poland | Supermarket | / | / | 5.4 | 13.0 | (Bielecka et al., 2021) |
Daily intake rate (DIR), the reference dose (RfD) and the hazard quotient (HQ) values of the studied heavy metals in walnuts_
| Heavy metals | Cr | Ni | Cd | Pb |
|---|---|---|---|---|
| DIR mg day-1 | 0.01995 | 0.00852 | 0.0000865 | 0.00128 |
| RfD | 1.5 | 0.02 | 0.001 | 0.0035 |
| HQ | 0.0133 | 0.4260 | 0.0865 | 0.3657 |
Comparison of walnut genotypes with respect to trace elements examined_
| Genotypes | Cr μg kg-1 | Ni μg kg-1 | Cd μg kg-1 | Pb μg kg-1 |
|---|---|---|---|---|
| 76 IGD-05 | 650.4±0.8 f | 243.9±1.3 h | 2.4±0.1 de | 55.9±0.4 c |
| 76 IGD-22 | 300.7±0.7 o | 167.2±2.3 k | 1.3±0.2 ijk | 13.7±0.2 r |
| 76 IGD-26 | 169.4±0.4 t | 71.5±0.3 t | 1.4±0.0 ijk | 15.9±0.4 p |
| 76 IGD-66 | 209.4±0.4 r | 150.3±1.0 m | 1.3±0.1 jk | 43.1±0.1 d |
| 76 IGD-94 | 601.9±0.7 g | 337.6±0.5 b | 1.9±0.1 g | 28.6±0.6 h |
| 76 KAR-03 | 313.1±0.4 n | 144.7±0.7 n | 1.3±0.1 jk | 20.5±0.4 mn |
| 76 KAR-05 | 236.8±0.3 q | 108.4±0.7 p | 1.2±0.0 k | 17.7±0.3 o |
| 76 KAR-09 | 264.6±0.4 p | 99.1±0.8 r | 1.4±0.1 ijk | 31.4±0.2 g |
| 76 KAR-12 | 419.5±0.3 k | 165.3±0.4 l | 2.7±0.2 c | 24.9±0.5 j |
| 76 KAR-45 | 343.0±0.4 m | 101.8±0.3 q | 1.4±0.1 ijk | 14.8±0.4 q |
| 76 TUZ-03 | 714.5±0.7 d | 305.2±0.7 d | 2.5±0.1 cd | 57.2±0.3 b |
| 76 TUZ-22 | 793.1±0.7 b | 298.7±0.4 e | 3.4±0.1 b | 82.9±0.6 a |
| 76 TUZ-36 | 745.5±0.5 c | 380.6±0.3 a | 4.0±0.1 a | 26.7±0.5 i |
| 76 TUZ-59 | 577.2±0.2 h | 291.1±0.3 f | 2.1±0.1 fg | 22.1±0.5 kl |
| 76 TUZ-82 | 540.2±0.4 i | 178.5±0.7 j | 1.8±0.2 gh | 21.4±0.7 lm |
| 36 KAG-02 | 387.4±0.8 l | 116.9±0.5 o | 1.6±0.1 hi | 19.9±0.2 n |
| 36 KAG-30 | 892.1±0.7 a | 267.2±0.7 g | 3.6±0.1 b | 35.1±0.3 f |
| 36 KAG-33 | 478.8±1.2 j | 318.3±0.6 c | 2.4±0.2 cde | 18.4±0.8 o |
| 36 KAG-51 | 198.6±0.4 s | 96.8±0.4 s | 1.5±0.1 ij | 40.0±0.2 e |
| 36 KAG-58 | 662.9±0.4 e | 213.5±0.7 i | 2.2±0.2 ef | 22.6±0.9 k |
| Minimum | 168.7 | 71.1 | 1.1 | 13.5 |
| Maximum | 893.1 | 381.2 | 4.2 | 83.7 |
| Std. error of mean | 28.1 | 12.1 | 0.1 | 2.2 |
| Average | 474.9 | 202.8 | 2.1 | 30.6 |
| LSD (0.05) | 1.4 | 1.1 | 0.3 | 1.1 |
| Sig. Level | *** | *** | *** | *** |