Figure 1
![Selenium content in soils across Poland (0.0–0.3 m)[Pasieczna 2018]](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/64726a78215d2f6c89dc72e9/j_oszn-2021-0013_fig_001.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=ASIA6AP2G7AKHLVY5MLQ%2F20260228%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20260228T133338Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEI3%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEaDGV1LWNlbnRyYWwtMSJHMEUCIFN8FXo4rqiId4cLCCbRVuk%2Fcw7MogKnNmBZ8KFjgMqBAiEAvFryefIW8ZqTl1v44Fej118Ojqnmn4IEWjlbnuwV0kYqvQUIVhACGgw5NjMxMzQyODk5NDAiDJbUO8HPqt2Vq0f2SSqaBWHudX2KAMjVLo959EfT7CxV5SrtuDv7gKh4thsVi2720wG75aRDZOCOnRuyktIWGkhv73Q0Z03qtSzfrKXHgF8ocsbAieQYJ6wCv2N3p3Zs%2BIyxAqvlnqqNK%2Fzq0HbdKsH4mPFYmtBCO4UergEhFn6Q4ne8Qcdp5mR%2BFLgFtYBgdG%2Fn6AhOC348XVI4t7o5uEiwpD%2BXszc0MC6AxVKKvHfgRLsiMKF0Aimkk7FpwlBOH%2F1BEbDwUE0u4tGyTA2ymLQhML%2BbhMiLTFizshbpH%2B9O6b415cnXX7KswResVAFb4GrWDMRfy%2BxHo2wABdttqeCsYjDDEIDDuk%2FGAzGVb3bVlgoNzTPCox%2FujjmWvthYO4UrJj8zxUwqj76unq7sKz%2BAHIk71jrGuMOHqelwMwKui1pi1jomJcgHAr%2BnoE4CDRtI3O3zWWdTd4vRf0flU7RdZ5zAMIi9A21X3FGT5XkB4trWMhJv7z1Lqt1Xj7LhRmC7FDhLc5dgIir0jXEs8tySCr5UozHt%2B56qkDJOw%2Ffka1bLpn6XKte6VR7DHY3sV%2FDY3QSqHg6oD1YssMuuvkA3s2k0NT%2FLoM21suLu%2BVrc5K8SeN%2B5I7ncxG4yysFRxO0qeHshVDi3sc%2B4Ky15DUKXzyVtGxwacB%2BRPkqRGdmAz8CDP57KYQSfSxWpPdt0GnROrG4YYQy6gal1oUyM746ES8P394w09ixF33LGE8XXq5UM1W5tk6o4SbL3FqDyVjMeoShtKSkX9jlJoiHGO9h1jTpYcXF2l2d65CNqeRAS4SxGm2OfYY0am4yqfmwxVJArE1rmTn8uV6y0uFE3IYnEC32lwXFdya7sCPVCl2PEGEjl4Gq%2F1DLiuH4SVe0Y%2F3dDQqGqfO3EnTDOy4vNBjqxAd0u4ekbc1fQ2%2BgIH10jK0S01Q6De4gq1JxEJ2Hy74%2FdfnVjSs8nVd19qsitK2tWcqALCw3YfyR2z5c%2Ff9itOCtc62%2B1gDPPEhgo%2FILf9yGZCKmOxjB4giEuTKDTFDkOYfjYFWv47rGjhp%2B%2BNF7foO8t6Qeez7svxAGWBIVISa2aLHBP%2BFdpy2fghkZEPJZUBaki2kHFQaso74e6Sg8%2Fwx3v7hEWzME9BY7vB6%2F%2BkgHcwQ%3D%3D&X-Amz-Signature=6b4d710b41778cca980791926116303512f7f14ac6481ff8658af4201284578e&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
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 | ||