| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Capsicum annuum | Fruit | 0.5 | 20.0 | 0.6 | * |
| Carica papaya | Fruit | 0.1 | 5.0 | -0.6 | * |
| Carthamus tinctorius | Flower | 20.0 | 26.0 | 1.9 | * |
| Carum carvi | Seed | 9.0 | 18.0 | 0.3 | * |
| Carum carvi | Fruit | 9.0 | 13.8 | 0.1 | * |
| Carya illinoensis | Seed | -- | 15.0 | 0.0 | * |
| Carya ovata | Shoot | 1.25 | 45.0 | 1.0 | * |
| Carya glabra | Shoot | 0.9 | 55.0 | 1.6 | * |
| Carya ovata | Seed | -- | 7.8 | -0.6 | * |
| Cassia tora | Seed | 8.0 | 10.0 | -0.4 | * |
| Castanea sativa | Seed | 2.0 | 5.0 | -0.9 | * |
| Castanea mollisima | Seed | 4.0 | 6.0 | -0.8 | * |
| Castanea dentata | Seed | 4.0 | 7.0 | -0.7 | * |
| Celosia cristata | Flower | -- | 9.0 | -0.8 | * |
| Chaenomeles lagenaria | Fruit | -- | 24.0 | 0.9 | * |
| Chamissoa altissima | Leaf | 2.0 | 23.0 | -0.1 | Tramil |
| Chenopodium album | Seed | -- | 5.0 | -0.9 | * |
| Cicer arietinum | Seed | 8.0 | 10.0 | -0.4 | USDA's Ag Handbook 8 and sequelae) |
| Cichorium endivia | Leaf | 1.0 | 16.8 | -0.3 | * |
| Cichorium intybus | Root | -- | -- | * |