Figure 1

Selenium forms depending on soil pH [Kabata-Pendias and Pendias 1999]
| redoX CONDITIONS | pH | MAIN FORMS OF SELENIUM | |
|---|---|---|---|
| HIGHLY OXIDATIVE | 7 | SeO42− | selenates |
| <2 | HSeO4−, H2SeO3− | ||
| transitory | >7 | SeO32− | selenins |
| <7,3 | HSeO3− | ||
| highly reductive | >3,8 | HSe− | selenides |
| <3,8 | H2Se0 | ||