| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Carthamus tinctorius | Seed | 1260.0 | 1324.0 | -0.5 | * |
| Carthamus tinctorius | Plant | -- | 17000.0 | 0.4 | * |
| Carthamus tinctorius | Flower | 620.0 | 4430.0 | -0.4 | * |
| Carum carvi | Fruit | 6426.0 | 8160.0 | 1.0 | * |
| Carum carvi | Seed | 1530.0 | 8160.0 | 0.7 | * |
| Carya illinoensis | Seed | 618.0 | 763.0 | -0.6 | * |
| Carya ovata | Shoot | 5250.0 | 33300.0 | 1.4 | * |
| Carya glabra | Shoot | 3800.0 | 40700.0 | 1.9 | * |
| Carya ovata | Seed | -- | 1095.0 | -0.6 | * |
| Casimiroa edulis | Fruit | 80.0 | 455.0 | -0.8 | * |
| Cassia tora | Seed | -- | 11700.0 | 1.4 | * |
| Cassia tora | Sprout Seedling | -- | 28100.0 | 2.6 | * |
| Castanea mollisima | Seed | 160.0 | 356.0 | -0.7 | * |
| Castanea dentata | Seed | 240.0 | 427.0 | -0.7 | * |
| Castanea sativa | Seed | 220.0 | 528.0 | -0.7 | * |
| Catalpa ovata | Fruit | -- | 2890.0 | -0.2 | * |
| Catha edulis | Leaf | -- | 2900.0 | -1.1 | * |
| Caulophyllum thalictroides | Root | 428.0 | 3890.0 | -0.4 | * |
| Ceiba pentandra | Seed | 2300.0 | 4700.0 | 0.1 | * |
| Celosia cristata | Flower | -- | 8910.0 | 0.9 | * |