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It is important to critically examine recycling claims. Ductile iron (DI) pipe manufacturing, which uses metals from recycled automobiles, releases a host of additional chemicals such as lead, mercury, manganese, zinc, chromium compounds, trimethylamine, xylene, methanol and phenol compared to iron pipe made from virgin iron ore. The production of PVC pipe using virgin material is less energy intensive than DI pipe using recycled materials, resulting in fewer environmental impacts for water infrastructure projects. It is therefore critical to review using a life cycle data perspective, which may in fact indicate even greater impacts. When examining embodied energy impacts, the cradle-to-gate stage (raw material supply, transport and manufacturing) of DI pipe production exceeds the embodied energy of the entire life cycle of the equivalent PVC pipe. Moreover, piping materials such as polyethylene (HDPE) and prestressed concrete cylinder pipe (PCCP) also represent greater impacts, even when not accounting for replacement of failed piping systems.

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