Microplastics (MPs) are an emerging pollutant in the aquatic environment, and this has gradually been recognized in the Asian region. This systematic review study, using the Scopus database, provides an insightful understanding of the spatial distribution of scientific studies on MPs in freshwater conducted across the Asian region, utilized sampling methods, and a detailed assessment of the effects of MPs on different biotic components in freshwater ecosystems, with special focus on its potential risks on human health. The results of this review indicate that research on microplastics in Asia has gained attention since 2014, with a significant increase in the number of studies in 2018, and the number of scientific studies quadrupled in 2021 compared to 2018. Results indicated that despite a significant amount of research has been conducted in many Asian countries, they were not distributed evenly, as multiple studies selected specific rivers and lakes. Additionally, around two-thirds of all the papers focused their studies in China, followed by India and South Korea. It was also found that most of the studies focused primarily on reporting the occurrence levels of MPs in freshwater systems, such as water and sediments, and aquatic organisms, with a lack of studies investigating the human intake of MPs and their potential risks to human health. Notably, comparing the results is a challenge because diverse sampling, separation, and identification methods were applied to estimate MPs. This review study suggests that further research on the dynamics and transport of microplastics in biota and humans is needed, as Asia is a major consumer of seafood products and contributes significantly to the generation of plastic litter in the marine environment. Moreover, this review study revealed that only a few studies extended their discussions to policies and governance aspects of MPs. This implies the need for further research on policy and governance frameworks to address this emerging water pollutant more holistically.

Food waste has become a critical issue in modern society, especially in the urbanized and fast-growing cities of Asia. The increase in food waste has serious negative impacts on environmental sustainability, water and land resources, and food security, as well as climate and greenhouse gas emissions. Through a specific case study in Da Nang City, Vietnam, this paper examines the extent of food waste generation at the consumption stages, the eating habits of consumers, food waste from households and service establishments, as well as prospects for the reuse of food waste as pig feed. The results of this study indicate that per capita food waste generation in Da Nang has increased from 0.39 to 0.41kg in 2016, 0.46 in 2017, and reached 0.52kg in 2018. According to the results of our consumer survey, 20% of respondents stated that they often generate food waste, 67% stated they sometimes do, and 13% stated they rarely do. Furthermore, 66% of surveyed households stated that their food waste is collected and transported by pig farmers to be used as feed for pigs. The use of food waste as feed for pigs is a typical feature in Da Nang. The study also found that there is a high level of consumer awareness and willingness to participate in the 3Rs (reduce, reuse, recycle) program, which was being initiated by the city government. In service facilities such as resorts and hotels, daily food waste reached 100–200 kg in large facilities and 20–120 kg in small facilities. This waste was also collected for use in pig farming. However, there has been a fall in demand for pig feed in line with a decrease in the number of pig farms due to the African swine fever epidemic that occurred during the implementation of this study. This paper suggests that there is a strong need to take both consumer-oriented waste prevention and waste management measures, such as waste segregation at source and introduction of effective food waste recycling techniques, to ensure that food waste can be safely and sustainably used as a “valuable resource” rather than “wasted.”

This paper analyses roles of integrated approach to establish a regional mechanism for sustainable hydropower development in the Mekong River Basin. Based on a critical review of the current trend of hydropower development, it argued that existing approach of uncoordinated Mekong mainstream hydropower development cannot ensure sustainable development; rather it causes negative impacts on food security, livelihoods, biodiversity, and ecosystem across the river basin, especially countries in Lower Mekong Basin (LMB), including Cambodia, Thailand and Vietnam. As a result, it fails to bring positive net benefits at both national and regional level. Specifically, if all proposed mainstream dams are constructed and fully operated, Lao PDR is the only economically winner of billions USD after 20 years, while Thailand, Cambodia, and Viet Nam are losers, and total net value will be minus 275 billion USD. Early recognition of the “nexus” interactions amongst hydropower development and cross-border food security, water security and livelihoods can minimise the risk of diplomatic conflicts and social unrest, and is only enabled when member states are willing to divert high-level government priorities from national interests to transboundary interests, as implementing the nexus approach throughout the river basin could contribute to reducing trade-offs between hydropower development and basin-wide socio-economy, and increase synergies through implementation of benefit-sharing mechanisms towards a win-win outcome. It recommends strengthening the Mekong River Commission via bolstered resources and coordinating authority, and encourages China to participate as a full member. It also argues that transboundary Environmental Impact Assessments (EIA) of river projects should be conducted to reflect the synergic and trade-off nexus effect across the whole river basin.