Selecting Simple Guidelines for Biodegradability

I Halogens, especially chlorine and fluorine and especially if there are more than three in a small molecule 

II Chain branching if extensive (quaternary C is especially problematic) 

IV Polycyclic residues (such as in polycyclic aromatic hydrocarbons), especially with more than three fused rings 

Gamberger et al. made these positive features mathematically quantifiable, by using alphabetic designations that allow simultaneous assessment of several of the conditions AI—III or BI-V. 

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