Assessment Methods

Life Cycle Assessment (LCA)

Life cycle assessment (LCA) is a tool to assess the potential environmental impacts of any stage in a product or service's life cycle, from the extraction of resources, production and consumption, to the reuse, recycling or final disposal. Reducing the use of plastic is essential to prevent leakage from the source in combating marine plastic debris. However, LCA research on plastics and plastic products indicates 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) found almost all plastic packaging has significantly less environmental impact than aluminium, glass, steel, and cardboard packaging. The ban on plastic bags has not been effective in reducing GHG emissions, especially in municipalities where they have been reused and recycled (Nishijima and Nakatani, 2016). Municipalities should find alternative products or materials for the disposal of their waste, or provide materials for recycling instead of plastic bags.

Japan's Plastic Circulation Cooperation scheme found the use of plastic packaging in distributing fruit (peaches and strawberries) to be efficient in reducing fruit damaged as a result of distribution truck vibration (Plastic Circulation Cooperation, 2017). Plastic packaging reduces food loss and environmental loads (GHG emissions 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. Plastic-packaged fruit reduced 69% of GHG emissions and 66% of energy consumption.  

Future studies should assess more comprehensive impacts through 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, a national LCI database should be established and developed to reduce any bias and ensure assessment accuracy and applicability. Thailand has been developing its LCI database for 20 years: introducing life cycle thinking in 1990, capacity building on human resources in 2002, establishing the database and its master plan (2004), promoting its application (2010), improving data quality (2013), and developing software (2015) (Gheewala, 2018).

Studies have been conducted globally to better utilise LCA, especially to tackle marine plastic debris. As LCA was originally developed for the 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 on community and ecosystems scales) are less developed (Woods et al., 2016). To fill the gap, a specific framework to assess the impact of marine plastic debris 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 also possibly move between compartments. Different compartments will generate different exposure pathways and cause varied effects depending on the receptors.

For instance, 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 which could disrupt the socio-economic as well as natural and cultural values of tourism sites such as beaches, coral reefs, and landscapes. The framework clearly indicates the damaging impacts of marine plastic debris, not only on ecosystem quality but also on human health and 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. Businesses create products based on the exclusive consideration of environmental impacts. For instance, they often choose plastic bottles instead of steel cans or glass bottles for packaging, based on limited environmental indicators. Adopting the comprehensive LCA across the whole business will highlight both the wider environmental impacts and a truly environment-friendly product. Vázquez-Rowe (2018) discussed the unmapped LCA marine debris impacts on the marine ecosystem conducted by Langlois et al. (2014). Vázquez-Rowe (2018) mentioned the urgent need to consider the impact of micro-plastics from 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 combating marine plastic debris, especially in ASEAN countries. They 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 and the socio-economic and cultural values will enrich the level of understanding of the LCA of plastics. In the future, such holistic life cycle thinking will be applied to business at all levels.