Table 2. Results of the currently conducted field studies regarding nickel and cobalt release from metallic working tools in the German hairdressing trade [4, 5].
| Symanzik et al. 2019 [ 4 ] | Symanzik et al. 2021 [ 5 ] | |||||
|---|---|---|---|---|---|---|
| Nickel positive | Nickel positive | Cobalt positive | ||||
| Metal tools | % | n/total | % | n/total | % | n/total |
| Scissors | 0 | 0/62 | 0 | 0/116 | 0 | 0/116 |
| Hair rollers | 0 | 0/45 | 0 | 0/60 | 0 | 0/60 |
| Whisks | 0 | 0/20 | 0 | 0/22 | 0 | 0/22 |
| Hand showers | 0 | 0/13 | 0 | 0/20 | 0 | 0/20 |
| Tail combs | 7.4 | 2/27 | 8.9 | 4/45 | 0 | 0/45 |
| Straight razors | N/T | N/T | 15.6 | 5/32 | 3.1 | 1/32 |
| Sectioning clips | 17.8 | 8/45 | 44.0 | 33/75 | 2.7 | 2/75 |
| Tweezers | 64.7 | 11/17 | 60.0 | 24/40 | 7.5 | 3/40 |
| Crochet hooks | N/T | N/T | 100 | 5/5 | 0 | 0/5 |
| Hair clips | N/T | N/T | 100 | 60/60 | 6.7 | 4/60 |
| Total | 9.2 | 21/229 | 27.6 | 131/475 | 2.1 | 10/475 |
N/T = not tested.