Expanding life cycle impact assessment to account for marine plastic emissions: a case study for the fishing industry

Purpose Fishing is a major source of plastic pollution, which is harmful to marine life. Life cycle assessment studies do not usually include plastic emissions in their inventory or impact assessment. There has been a recent surge of methodological development to include plastic impacts in life cycle impact assessment (LCIA). This study of anchoveta and cod fishing included dissipative plastic emissions in the inventory data and tests currently available characterisation factors for plastic pollution impacts to identify their importance for ecosystem quality damage.

Methods Life cycle inventory (LCI) data was gathered for two systems that produce 1 tonne of fish product (anchoveta fishmeal, consumer packaged cod). LCIA calculations were performed using IMPACT World+ to calculate ecosystem quality damage. In addition, plastic impact pathways for the physical effects from microplastics on biota (both water and sediment-dwelling organisms) and entanglement were included.

Results and discussion The fishing stage dominates the ecosystem quality (EQ) damage results for both systems. For cod fished with gillnets, production of antifouling coating is the dominant contributor. Entanglement results completely dominate the picture for anchoveta. Overall, freshwater ecotoxicity (long term) causes the largest overall EQ damage. The emissions that contribute the most to freshwater ecotoxicity (long term) are metals from fishing gear production (mainly associated with the lead in the bottom rope), followed by polyethylene production for the cod system. For anchoveta, production of phosphoric acid and iron sulphate for fishmeal processing contribute the most. The second most important impact category is climate change (long term), due to emissions of fossil-derived carbon dioxide, as well as refrigerant R500 for anchoveta. Even with 100% fragmentation into microplastics, physical effects on biota account for less than 0.1% of the total EQ damage.

Conclusions Including the impacts associated with plastic emissions is important in LCAs where plastic materials or products are used. Without the inclusion of the plastic impacts, LCAs will not capture all of the impacts that plastics can have on the ecosystem. This study shows that whether parts, or the whole of the gear (including ropes) are included affects the importance of the mismanaged waste losses in the value chain, as well as the microplastic impacts associated with fishing gear losses at sea. The timescale for when lost fishing gear can still entangle organisms is extremely important for the overall damage caused by fishing and should be investigated further.