A review of the LCA literature investigating the methods by which distinct impact categories are compared.

An in-depth literature review was carried out, highlighting previous life cycle assessments studies on the environmental impact of food packaging solutions. The aim was to analyse the different indicators used and the relationships thereof, the various methods weighing distinct damage categories and the implicit trade-offs between the various environmental burdens. The results of 40 studies were analysed. The frequency of comparisons between different impact categories was counted. The frequency of correlation between impact categories was measured in 270 comparisons as well as the trade-off levels in instances where changes in impact were not correlated. Methods by which authors combined distinct categories were reviewed. It was found that the most frequently used indicators were correlated in > 93% of comparisons. Authors used subjective or often undefined methods of combining and comparing distinct categories. Methods used to combine distinct impact or damage categories can be affected by subjective value judgment and can generate arbitrary comparisons. Suggestions are made to improve such methods. [ABSTRACT FROM AUTHOR]