Biodegradable Chemicals

Good day All

The general definition of biodegradable is anything that biologically degrades with time. This time can be 1000 years, 2days or any amount of time. So looking at this definition, then everything is technically biodegradable.

Some chemicals used for cleaning and disinfection (especially in food industry) has also been termed biodegradable. The WHO said Sodium-diChloro-Isocyanurate is a biodegradable chemical. 

So if certain chemicals are stamped biodegradable then this deviates from the general definition of biodegradability. 

So what is actually the meaning of biodegradability when it is being used to stamp products as biodegradable. Is there a time to degrade which is used as reference. Example, anything taking >5 years is termed un-biodegradable. Or what is the criteria to stamp a chemical as biodegradable?

Same as with labs that terms all parameters going through a 0.45um filter as "soluble". But the same parameters termed soluble passing through a 0.45um filter is not soluble passing though a 0.03um filter. So the 0.45um size was used as reference to create the universal definition of soluble.