Purpose
The increase of shellfish production has raised environmental concerns, i.e., enrichment and redistribution of nutrients and energy consumption. Efforts assessing the environmental burdens arising from the expansion of shellfish production have been made using the life cycle assessment (LCA) methodology. Although LCA has been extensively applied and reviewed in aquaculture systems, shellfish production remains scarcely studied. The objective of this review is to identify methodological trends, highlight gaps and limitations, and provide guidelines for future studies.
Methods
A systematic literature review was applied to scientific studies published up to 2021. A total of 13 documents were shorted by abstract and full text-screening. Literature meeting the inclusion criteria were further analyzed in six different aspects of a LCA (functional unit, system boundaries, data and data quality, allocation, impact assessment methods, interpretation methods). Discussion and guidelines are provided for each reviewed aspect.
Results and discussions
Shellfish LCAs differ considerably from other aquaculture studies mainly because shellfish avoids the allocation of impacts derived from the production of fishmeal. Co-products are present when the shellfish is processed, e.g., in canned products. Furthermore, shellfish studies do not take into account the positive credits from the removal of nutrients from the ecosystems and from the valorization of the shellfish waste (shell and organic remains). Limited information was found for countries outside Europe and species different from mussels. Despite the variability on goals and scopes of the studies, methodological trends were found. The local impacts of the shellfish with the farming area and the impacts on biodiversity have not been included into the studies.
Conclusions and recommendations
Effort should be made in providing the data associated with the fore-background system within the studies in order to improve transparency and to allow the reproduction of the results. Information regarding the natural condition of the cultivation area should be provided as the shellfish production depends mainly on non-anthropogenic conditions. Application of biodiversity assessment methodologies should be encouraged, despite their limitations.
Electricity data is one of the key factors in life cycle assessment (LCA). There are two different approaches to model electricity and to apply average or marginal data in LCA studies. Marginal data is used in consequential whereas average data is considered in attributional studies. The aim of this study is to provide the long-term marginal technology for electricity power generation in Colombia until 2030. This technology is one capable of responding to small changes in demand on the market and is an important issue when assessing the environmental impacts of providing electricity. Colombia is a developing country with a national power grid, which historically has been dominated by Hydropower rather than fossil fuels. This particularity makes Colombian national power grid vulnerable to climatic variations; therefore, the country needs to introduce renewable resources into the power grid. This study uses consequential life cycle assessment and data from Colombian national plans for capacity changes in the power grid. The results show that whereas marginal electricity technology would most probably be Hydropower, Wind and Solar power are projected to reach more than 1% of the national power grid by 2030.
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