The open source journal PLOSOne had a recent article of potential interest to the P2 community. The researchers used TRI data to determine the extent to which adoption of P2 practices reduces pollution substitution. They found that adoption of P2 techniques reduces toxic air and water releases equally, but it is associated with increases in treated and recycled wastes over total releases to the environment. The conclude that:
"We find that adopting greater numbers of P2 techniques contributes to increases in wastes emitted for treatment and recycling over total releases. Specifically, process and equipment modifications have a greater effect than do raw material, product, and procedure modifications. These results suggest that the potential of P2 techniques in reducing or eliminating overall reliance on toxics in manufacturing may be limited, as facilities focus on reducing releases to the environment through combining end-of-pipe and in-process waste management strategies with particular types of P2 techniques that do not necessarily address the root causes of toxic wastes. Thus, pollution control policy should emphasize waste minimization, considering the life cycle of toxics, and prioritize the use of raw material and product modification. As noted by Ranson et al. [6], raw material and product modifications are likely to be more resource intensive, thus grants and technical assistance programs should target them."
You can download the full article at https://doi.org/10.1371/journal.pone.0224868.