This word is not acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. The capacity of a material to decompose over time as a result of biological activity, especially to be broken down by microorganisms

"According to scientific methods, the toxicity and biodegradability of a mixture must be tested on the mixture as a whole."

biodegradation    biodegradable