TABLE 2.
Genotoxic Endpoints for Six Metals
| Chromium-6 (Cr6+) | Arsenic (As) | Nickel (Ni) | Lead (Pb) | Mercury (Hg) | Zinc (Zn) | |
|---|---|---|---|---|---|---|
| National Toxicology Program classification | 1 | 1 | 1 (Ni compounds) | 2 | 3 | 3 |
| Substance Priority List rank | 17 | 1 | 58 | 2 | 3 | 75 |
| Chromosomal damage | * | |||||
| DNA methylation | * | |||||
| DNA–protein cross-linking | ||||||
| Micronuclei formation | * | |||||
| Sister-chromatid exchange | ||||||
| DNA repair inhibition | ||||||
| Gene mutation | * | |||||
| Chromosomal aberrations | * | |||||
| DNA fragmentation | * | |||||
| DNA strand breaks | * | |||||
| Telomere alteration |
Represents some studies with preventive effects.
Note. Table 1 presents the number of published studies that identified the genotoxic endpoint from a search of toxicological profiles and literature using PubMed conducted on October 17, 2022. Search terms included: endpoint induced by X metal exposure (e.g., telomere alteration induced by arsenic metal exposure, only lead and zinc were searched as Pb and Zn). The shading is based on the number of given genotoxic endpoints studied: green = 1–10; yellow = 11–24; and red = >24. A lack of shading indicates no studies were found. For the National Toxicology Program classification: 1 = known carcinogen; 2 = reasonably anticipated to be a human carcinogen; and 3 = not classified by the National Toxicology Program. For the Substance Priority List rank: 1 represents the highest priority. The only form of chromium classified as carcinogenic to humans is hexavalent chromium (Cr6+).