1. Notion of impact in LCA

Impact involves the action of a source system on a target system. The source system considered here is a human activity. The target system is a component of the environment (man, fauna, flora and ecosystem). Impact can be defined as a change in state of the target system due to the action of the source system. Thus, an impact analysis begins by defining the initial state of the target. The problem is then to track changes in the target's state. The changes observed constitute the impact. Finally, it should be noted that direct impacts on the target generally generate a succession of secondary impacts. For example, a substance released into an environmental medium can generate different types of successive effects:

• effect on the physical environment (modification of physico-chemical characteristics) ;

• effect...