There is still a lack of reliable data and short of scientific knowledge on marine plastic debris. Although we should take some actions, based on the precautionary principle, we also need to enrich scientific knowledge in various fields, such as monitoring method, flow of macro- and microplastics in the ocean, impact of to ecosystem and human health, material flow analysis, life cycle assessment, and others. RKC-MPD is planning to organise some seminars and working groups to review the current status of relevant research and to facilitate future research in the region.
Life Cycle Assessment
Life Cycle Assessment (LCA) is a tool to assess the potential environmental impacts of any stage in life cycle of products or services, from extraction of resources, production, consumption, to reuse, recycling, or final disposal. In the context of combatting marine plastic debris, reducing the use of plastic is essential to prevent leakage from the source. However, some LCA research on plastics and plastic products indicate that replacing plastics with alternative materials is not always an environmentally friendly choice, at least when it comes to climate change impact.
Ayudhaya (2014) compiled some comparisons that emphasise that plastics are still essential to address climate change. Chaffee and Yaros (2014) found that conventional polyethylene bags are more environmentally friendly than paper bags and compostable bags, especially in terms of fossil fuel use, municipal solid waste, greenhouse gas (GHG) emission, and freshwater use. Huang and Ma (2004) revealed that almost all kinds of plastic packaging have significantly less environmental impact than aluminium, glass, steel, and cardboard packaging. The ban on plastic bags was not effective in reducing GHG emission, especially in municipalities where they have been reused and recycled (Nishijima and Nakatani, 2016). Municipalities should find alternative products or materials for disposing of their waste or provide materials for recycling instead of plastic bags.
The Plastic Circulation Cooperation in Japan found that the use of plastic packaging in distributing fruit (peaches and strawberries) is efficient in reducing the amount of fruit damaged as a result of vibration in distribution trucks (Plastic Circulation Cooperation, 2017). Plastic packaging reduces food loss and environmental loads (GHG emission and energy consumption). For example, in an average distribution distance of 324 km, food loss from plastic-packaged fruit was only 0.1%, compared with 73.4% of fruit without plastic packaging. As for impacts, plastic-packaged fruit reduced 69% of GHG emissions and 66% energy consumption.
Future studies should assess more comprehensive impacts along the life cycle of plastics, focusing not only on GHG emissions and energy consumption but also end-of-life impacts, such as littering potential, human toxicity, and aquatic ecotoxicity. To promote such research, national LCI database should be well established and developed to reduce any bias and ensure accuracy and applicability of assessment. Thailand has been developing its LCI database for 20 years: introducing life cycle thinking (since 1990), capacity building on human resources (since 2002), establishing the database and its master plan (since 2004), promoting its application (since 2010), improving data quality (since 2013), and developing a software (since 2015) (Gheewala, 2018).
Globally, studies have been conducted to better utilise LCA, especially to tackle the emerging marine plastic debris issue. As LCA was originally developed for impact assessment of land-based industries on mainly terrestrial and freshwater ecosystems, impact indicators for major drivers of marine ecology (i.e. sensitivity of marine biota with plastic debris at community and ecosystems scales) are less developed (Woods et al., 2016). To fill the gap, a specific framework to assess marine plastic debris impact was developed (Verones et al., 2020) (Figure 1). The framework considers three categories of plastic: macro (>5 mm), micro (<5 mm), and nano (<1 µm). Each category can end up in air, terrestrial, freshwater, or marine compartments, and possibly move between compartments. Different compartments will generate different exposure pathways and cause varied effects depending on the receptors. Nano-plastics could be toxic to humans if inhaled. Together with micro-plastics, nano-plastics could be ingested by invertebrates and vertebrates in terrestrial and freshwater compartments, which could be toxic to humans if they ingest such animals, create ecotoxicity, have physical effects on biota, and affect invasive species. In the marine compartment, macro-plastics are exposed through entanglement and accumulation that could disrupt socio-economic as well as natural and cultural values of tourism sites such as beaches, coral reefs, or landscapes. The framework clearly indicates the damaging impacts of marine plastic debris, not only on ecosystem quality but also on human health as well as on socio-economic and cultural values.
Figure 1. Framework for Marine Plastic Debris Assessment in LCA
Source: Verones et al. (2020).
Sonnemann (2018) highlighted the integration of holistic life cycle thinking into business practices. Current businesses create products based on the exclusive consideration of environmental impacts. For instance, businesses often end up choosing plastic bottles instead of steel cans or glass bottles for packaging, based on limited environmental indicators. Adopting the comprehensive LCA in the entire business will show the wider environmental impacts and a truly environment-friendly product. Vázquez-Rowe (2018) discussed the unmapped marine debris impacts during LCA of the marine ecosystem conducted by Langlois et al. (2014). Vázquez-Rowe (2018) mentioned the urgent need to consider micro-plastics impacts due to direct littering in the marine ecosystem, including human toxicity from seafood, ecosystem quality impacts on the different trophic levels such as seabirds, and loss of resources and revenue.
Such global efforts will inspire similar efforts to better utilise LCA in combatting marine plastic debris, especially in ASEAN countries. Such efforts will consider plastics in their entire life cycles in a more holistic way, rather than exclusively measuring the indicators of GHG emissions and energy consumption. Considering the damaging impacts of plastic on human health as well as on socio-economic and cultural values will enrich the state of understanding on the LCA of plastics. In the future, such holistic life cycle thinking will be applied to business at all levels.