Follow CDE on Socials Dr He Jianzhong Professor Department of Civil and Environmental Engineering Dr Karina Gin Associate Professor Department of Civil and Environmental Engineering Environmental Engineering Reducing microplastics’ impact on our water environment 3 Nov 2022 | Highlights Community Follow CDE on Socials Through researching on how microbial populations can be used to make microplastics in our seas less harmful to marine animals, and determining that these particles can result in physiological changes in seaborne biota, two Department of Civil and Environmental Engineering researchers hope to shed light on microplastics’ impact on marine ecosystems. The world’s efforts at trying to stay clean and hygienic may have inadvertently polluted the Earth’s waterways with microplastics-smaller, finer particles that result from the wearing and tearing of plastic waste. This problem became even more pronounced during the pandemic, where our reliance on single-use plastics to keep us clean meant we were discarding more plastics each day than ever. Through Earth’s waterways, microplastics have travelled to just about every corner of the globe; from sea urchins in Brazil to the drinking water of Lagos, the largest city in West Africa-and found even in human blood. Microplastics’ small size, defined as being less than 5 mm in length, makes them harder to be detected in our waters and easier to be consumed by almost all organisms, big and small. Their presence has been shown to harm marine life and damage human cells. Furthermore, microplastic particles sometimes come into contact with pollutants, in particular persistent organic pollutants such as herbicides and pesticides, and bacteria, which then latch onto the particles. This problem is even more pronounced in water because these chemicals can travel vast distances in liquids without dissolving. Using microbial populations to make microplastics less harmful Professor He Jianzhong and Associate Professor Karina Gin, from the Department of Civil and Environmental Engineering at the NUS College of Design and Engineering, are on a mission to lessen the impact of microplastics on our marine and river environments. “There have been a few lab-based demonstrations of persistent organic pollutants adhering to microplastics and some recent studies have found pollutant concentrations orders of magnitude higher than the surrounding environment on microplastics recovered from marine and estuarine environments,” said He. Together with her team, He recently began investigating how biological processes, through the use of microbial populations, could be used to degrade and detoxify the persistent organic pollutants bound to the surface of microplastics and the microplastics themselves. The researchers have identified the potential microbial populations that can break down the microplastics present in Singapore’s coastal and marine environments. The team is now working to determine which persistent organic pollutants are commonly found on microplastics in Singapore. A realistic need to reduce microplastics’ impact Going forward, He and her team will develop biological systems and processes that can remove the toxins from these chemicals while breaking down the microplastic carrier at the same time. In doing so, He and her team turn to biological tools, such as microbes which are adaptive and low-cost. Using such tools, they aim to explore new biological pathways to treat the myriad of pollutants in Singapore and elsewhere. Ultimately, He understands that even if society chooses to eliminate the use of plastics today, removing them from our environment would take centuries. She sees an urgency for scientific research to develop new ways to reduce the impact of microplastic today as the world works towards a plastic-free future. “Rather than considering ways to eliminate microplastics from the marine environment, it’s more realistic to focus on developing technologies that can mitigate the most dramatic impacts of microplastics and other contaminants in our seas and on our beaches, while encouraging practices that reduce the volume of plastics that are produced, consumed and discarded,” said He, who is also an Elected Fellow of the Royal Society of Biology in the UK in 2020 and one of ten named as “Inspiring Women in Science and Technology” by the World Economic Forum in 2016. Pioneering a new approach to study microplastic toxicity in marine animals Meanwhile, Gin and her team are studying how new contaminants interact with microplastics, and how the biofilm communities that reside on microplastics have become more resistant to the medicine that treats the diseases they cause. “Microplastic pollution is a threat to global marine ecosystems, and it is important to understand the hazard risk posed to local coastal ecosystems and its biota,” said Gin, who received the Dean’s Chair Award from 2017 to 2019. “We study the impacts of microplastics on ecosystem health and the environment through three interlinking research themes: field surveillance of microplastics along Singapore’s tropical coastline; modelling the transport and fate of plastics; and evaluating the ecotoxicology through model marine organisms.” In parallel, Gin and her team focus on how microplastics are moving in Singapore’s waters and how they can be toxic to green mussels. To find out how toxins carried by microplastics affected physiological changes in marine biota, the team relied on the enhanced integrated multi-biomarker response (EIBR) model to measure changes across eight biomarkers in Perna viridis, the Asian green-lipped mussel. These biomarkers include those at the molecular, cellular, and physiological levels. The researchers found that the Asian green-lipped mussels could not eject smaller microplastic particles, ultimately leading to physiological changes and a weakened state for filtering out seawater. Moreover, ingesting microplastics could make these sea creatures more susceptible to other environmental stress, such as lower oxygen levels in the water or changes in water temperature. This research was the first time the EIBR model was used to assess if microplastics did indeed induce toxicity in marine animals. The team found that the model was an effective ecotoxicological platform that allowed them to determine how toxic microplastics were. It also gave them flexibility in modifying biomarker variables depending on research priorities. “Such an approach will be useful to environmental managers as a practical tool to assess the ecological impacts of microplastic pollution in aquatic environments and food chains, as demonstrated in this study,” the team noted. Understanding marine plastics’ devastating impact “If you take a walk along the beach today, you can still see the visual impact of plastics pollution from the oceans,” Gin pointed out. “What we don’t see are the devastating consequences marine plastics have on marine organisms. Through our research, we can better understand such implications and motivate people to adopt lifestyle changes that will reduce plastic waste.” Indeed, given that Southeast Asia is one of the world’s hotspots for microplastic pollution and potential maritime transboundary migration, more effort is also needed on our part to elucidate-and mitigate-the ramifications of such contamination. With greater regional and international collaboration and cooperation, the problem of plastic pollution will hopefully not seep into the next generation. People He Jianzhong ▏ Professor, Department of Civil and Environmental EngineeringGin Yew-Hoong, Karina ▏ Associate Professor, Department of Civil and Environmental Engineering Related Departments/ Centres Department of Civil and Environmental Engineering If you are interested to connect with us, email us at cdenews@nus.edu.sg More Research Features
