environmental availability

https://doi.org/10.1351/goldbook.14638
Portion of the total amount of a substance present in the environment that is involved in a particular process and is subject to physicochemical and biological modifying influences.
Source:
PAC, 2009, 81, 829. (Glossary of terms used in ecotoxicology (IUPAC Recommendations 2009)) on page 877 [Terms] [Paper]