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Distinguished Visiting Professor Dr John Cherry has won the 2020 Stockholm Water Prize

Distinguished Visiting Professor Dr John Cherry from Department of Earth Sciences has won the 2020 Stockholm Water Prize – the first groundwater expert receiving this honour. Dr Cherry is named the Laureate for discoveries that have revolutionised our understanding of groundwater vulnerability. Being a world-renowned hydrogeologist and a leading authority on the threats to groundwater from contamination, Dr Cherry is the creator of the academic field contaminant hydrogeology who has changed the scientific paradigms of groundwater research. His research has raised awareness of how groundwater contamination is growing across the world and has led to new and more efficient methods to tackle the problem. The Stockholm International Water Prize Nominating Committee said, “with the Stockholm Water Prize, John Cherry is recognised for his contributions to science, education, practice and for translating his well-earned stature into a passionate and highly effective advocacy for groundwater science to inform current and future policies, laws and collective deliberations that governments must establish to protect water, our most essential and yet most imperilled resource.” Contaminant hydrogeology studies how chemicals and waste leaches into the groundwater. A geological engineer by training, Dr Cherry has pioneered in-depth systematic approaches, including measurement tools and deep insights into groundwater transport processes. Through highly collaborative field experiments, he has developed new ways to monitor, control and clean up contaminated groundwater. Stockholm International Water Institute’s (SIWI) Executive Director Torgny Holmgren commented, “Dr Cherry has made us aware of how much we depend on groundwater and that it is all too often threatened by contamination. We are very grateful for his invaluable contributions in helping us understand how we can protect the world’s groundwater from the threats it faces”. More about Stockholm Water Prize The Stockholm Water Prize is an international water award presented annually since 1991. For 30 years, the world’s most prestigious water award, the Stockholm Water Prize, has honoured women, men and organizations for extraordinary water-related achievements. Stockholm Water Prize is awarded by SIWI in cooperation with the Royal Swedish Academy of Sciences and presented by the Swedish King H.M King Carl XVI Gustaf, the official patron of the Prize.

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The Theme-based Research Team (4th from the right: Prof. X.Y. Li, the leader of this project; 1st from the right: Prof. Kenneth Leung)

HKU researchers develop novel wastewater treatment process to effectively remove health hazardous chemical contaminants

Globally, there is a growing concern regarding the presence of trace emerging contaminants such as retinoids and oestrogenic endocrine disrupting chemicals (EDCs) in aquatic environments. Retinoids such as retinoic acids and their metabolites, which are the derivatives of vitamin A, can cause abnormal morphological development in amphibians, fish, and snails at elevated levels. Oestrogenic EDCs like alkylphenols and bisphenol A are environmental oestrogens that can induce feminization of male fish and abnormal development in aquatic organisms. Sewage effluents are a significant source for the continuous input of these contaminants into the aquatic environment. High levels of these chemical contaminants are commonly found in sewage effluents discharged from conventional sewage treatment plants (STPs).  An interdisciplinary team led by the University of Hong Kong (HKU) has developed a novel wastewater treatment system that can effectively remove conventional pollutants, and recover valuable resources such as phosphorus and organic materials (i.e., carbon fibres and volatile organic acids).  This novel system combines chemically enhanced primary sedimentation (CEPS) of sewage with acidogenic fermentation of sludge in tandem (Image 1).  A series of laboratory experiments were conducted to prove that this novel system can effectively remove trace emerging chemical contaminants from wastewater and is more cost effective compared with conventional wastewater treatment systems.  The results of this study have been recently published in Water Research and Environment International. Moreover, in collaboration with the Nanshan Sewage Treatment Plant in Shenzhen, a pilot wastewater treatment system adopting the novel treatment process has been under construction in Shenzhen since 2019. It will come into operation and testing by this summer if the COVID-19 outbreak subsides (Image 2).   Background In the past few years, Professor Xiao-Yan Li of the Department of Civil Engineering who led the interdisciplinary research project, has been collaborating with Professor Kenneth Leung from HKU School of Biological Sciences and the Swire Institute of Marine Science to examine the levels and removal efficiencies of retinoids and oestrogenic EDCs from wastewater by the novel wastewater treatment process developed by the research team, and to compare that with the conventional STPs. The research team first examined the levels and removal efficiencies of retinoids and oestrogenic EDCs in Shatin, Stanley and Stonecutters Island STPs in Hong Kong by collecting wastewater and sludge samples from different stages of the treatment process, and analyzing the samples for retinoids and oestrogenic EDCs using liquid chromatography with tandem mass spectrometry (LC-MS/MS).  Secondly, a series of laboratory experiments were conducted using a small-scale pilot plant of the novel wastewater treatment process.  Samples of wastewater and sludge were taken for the chemical analysis using the protocols developed by Professor Leung’s team.   Key Findings The results indicated that the three STPs can only remove an average of 57% of retinoids (range: 41-82%) and an average of 54% of oestrogenic EDCs (range: 31-79%) from wastewater influents (this work was published in Environment International).   Using the novel treatment system operated under laboratory conditions, the CEPS process alone was demonstrated to be 16 - 19% more effective in removing retinoids and EDCs than the conventional STPs. 65 - 80% of retinoids and 72 – 73% of EDCs can be removed from the CEPS process (Image 3). After acidogenic fermentation of the CEPS sludge, 50 – 58% of retinoids and 47 – 50% of EDCs were further removed from the supernatants of sludge (this work has been recently published in Water Research).  Compared to the conventional STPs, the novel treatment system integrating CEPS with acidogenic fermentation of sludge is comparatively more efficient in removing emerging chemical contaminants from wastewater, and hence could reduce their environmental impacts. In terms of cost effectiveness, the CEPS process has been shown, by other studies, to be more cost-effective than the conventional wastewater treatment process. For instance, the cost of CEPS for wastewater treatment is less than a half of that of the secondary wastewater treatment (i.e., activated sludge process). On one hand, acidogenic fermentation of CEPS sludge can further reduce the treatment cost by recovering organic carbon and phosphate resources from the sludge as the harvested organic carbon and phosphate can be utilized to produce carbon fibers and fertilizers respectively. On the other hand, the acidogenic fermentation of CEPS sludge can provide additional removal of pollutants. The novel treatment process, therefore, offers win-win outcomes.   The Way Forward Professor Li, who led the study, said: “When the pilot wastewater treatment system in Shenzhen comes into operation and testing, we hope to demonstrate that this innovative technology will use less energy, generate cleaner effluent and recover more useful materials from the sludge.”   Professor Leung said, “We are very pleased to gather evidence for supporting our hypothesis that our novel sewage treatment system can effectively remove the emerging chemical contaminants. With the scaled-up pilot plant in Shenzhen, we will further investigate the removal efficiency of other classes of common pollutants by this novel treatment system.” Regarding its potential application in Hong Kong, Professor Li added, “Our system can be easily retrofitted onto the existing STPs in Hong Kong, like add-on units. For instance, the pilot system will be connected to the existing Nanshan STP in Shenzhen to test its performance. If successful, this will pave the way for advancing wastewater treatment in China and beyond.”  This innovative research is funded by Theme-based Research Scheme of Research Grants Council of the Hong Kong SAR.     The published articles: Zhou G.J., Lin L., Li X.Y., Leung K.M.Y. 2020. Removal of emerging contaminants from wastewater during chemically enhanced primary sedimentation and acidogenic sludge fermentation. Water Research 175: 115646. Link to the article: https://www.sciencedirect.com/science/article/pii/S0043135420301822   Zhou G.J., Li X.Y., Leung K.M.Y. 2019. Retinoids and oestrogenic endocrine disrupting chemicals in saline sewage treatment plants: Removal efficiencies and ecological risks to marine organisms. Environment International 127:103-113. Link to the article: https://www.sciencedirect.com/science/article/pii/S0160412018327570   Image 1: The novel wastewater treatment system developed by the Theme-based research team led by HKU: Fe-based CEPS with side-stream sludge acidogenesis in relation to the conventional wastewater treatment process. Image 2: The HKU research team’s pilot wastewater treatment plant adopting the novel treatment process under construction in Shenzhen, including the control system, a CEPS tank, an acidogenic fermenter and a moving bed biofilm reactor (MBBR) and carriers. Image 3: The novel wastewater treatment process and removal of emerging contaminants during this process. Image 4: Prof. X.Y. Li (Left) and Prof. Kenneth Leung (Right) taking this picture with the HKU Distinguished Visiting Professor John Giesy from Canada.  

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Professor Che Chi Ming receives First Class Award of 2019 Shenzhen Science and Technology Prize from the Shenzhen Science and Technology Innovation Commission (SZSTI)

HKU chemical scientist Professor Che Chi Ming receives First Class Award of 2019 Shenzhen Science and Technology Prize

Professor Che Chi Ming Professor Che Chi Ming, Chair Professor and Zhou Guangzhao Professorship in Natural Sciences at the Department of Chemistry of Faculty of Science, the University of Hong Kong (HKU) has received the First Class Award of 2019 Shenzhen Science and Technology Prize from the Shenzhen Science and Technology Innovation Commission (SZSTIC). Professor Che specialises in synthesis of inorganic and organic chemistry, inorganic and metal organic photochemistry, photocatalysis and bioinorganic medicine, and has significant achievements in the studies of high-valent metal ligand multiple bond complex, inorganic and metal organic light emitting materials, photo-induced electrons and atom transfer reaction, as well as asymmetric olefin epoxidation. Professor Che thanks his research team members including Dr Cheng Gang, Dr To Wai Pong, Dr Lok Chun Nam and Dr Zou Taotao for their dedicated hard work to make the research a success. Professor Che has made innovative discoveries in inorganic photochemistry, electron transfer in multinuclear compounds and atom transfer chemistry. In particular, his outstanding contribution to the study in reactive metal-ligand multiple bonded complexes won him the First Class prize of the State Natural Science Award in 2007. He is the first Hong Kong scientist to have received the honour. The Shenzhen Science and Technology Prize was established in accordance with the Shenzhen Science and Technology Prize Incentives and related implementing rules. It is seen as the important window for the scientific and technological development in Shenzhen, which provides the essential motivation for the realisation of innovative breakthroughs in the city. Professor Che is the first HKU scholar to receive the award. Professor Che was elected to the Chinese Academy of Sciences as academician in 1995, the US National Academy of Sciences as foreign associate in 2013, the Hong Kong Academy of Sciences as founding member and vice president in 2015. Professor Che is now the Director of the Synthetic Chemistry State Key Laboratory, HKU-CAS Joint Laboratory on New Materials and Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis. He also serves the editorial board for Chemical Review and other internationally recognised academic journals.

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Distinguished Visiting Professor Dr John Cherry has won the 2020 Stockholm Water Prize

Distinguished Visiting Professor Dr John Cherry from Department of Earth Sciences has won the 2020 Stockholm Water Prize – the first groundwater expert receiving this honour. Dr Cherry is named the Laureate for discoveries that have revolutionised our understanding of groundwater vulnerability. Being a world-renowned hydrogeologist and a leading authority on the threats to groundwater from contamination, Dr Cherry is the creator of the academic field contaminant hydrogeology who has changed the scientific paradigms of groundwater research. His research has raised awareness of how groundwater contamination is growing across the world and has led to new and more efficient methods to tackle the problem. The Stockholm International Water Prize Nominating Committee said, “with the Stockholm Water Prize, John Cherry is recognised for his contributions to science, education, practice and for translating his well-earned stature into a passionate and highly effective advocacy for groundwater science to inform current and future policies, laws and collective deliberations that governments must establish to protect water, our most essential and yet most imperilled resource.” Contaminant hydrogeology studies how chemicals and waste leaches into the groundwater. A geological engineer by training, Dr Cherry has pioneered in-depth systematic approaches, including measurement tools and deep insights into groundwater transport processes. Through highly collaborative field experiments, he has developed new ways to monitor, control and clean up contaminated groundwater. Stockholm International Water Institute’s (SIWI) Executive Director Torgny Holmgren commented, “Dr Cherry has made us aware of how much we depend on groundwater and that it is all too often threatened by contamination. We are very grateful for his invaluable contributions in helping us understand how we can protect the world’s groundwater from the threats it faces”. More about Stockholm Water Prize The Stockholm Water Prize is an international water award presented annually since 1991. For 30 years, the world’s most prestigious water award, the Stockholm Water Prize, has honoured women, men and organizations for extraordinary water-related achievements. Stockholm Water Prize is awarded by SIWI in cooperation with the Royal Swedish Academy of Sciences and presented by the Swedish King H.M King Carl XVI Gustaf, the official patron of the Prize.

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The Theme-based Research Team (4th from the right: Prof. X.Y. Li, the leader of this project; 1st from the right: Prof. Kenneth Leung)

HKU researchers develop novel wastewater treatment process to effectively remove health hazardous chemical contaminants

Globally, there is a growing concern regarding the presence of trace emerging contaminants such as retinoids and oestrogenic endocrine disrupting chemicals (EDCs) in aquatic environments. Retinoids such as retinoic acids and their metabolites, which are the derivatives of vitamin A, can cause abnormal morphological development in amphibians, fish, and snails at elevated levels. Oestrogenic EDCs like alkylphenols and bisphenol A are environmental oestrogens that can induce feminization of male fish and abnormal development in aquatic organisms. Sewage effluents are a significant source for the continuous input of these contaminants into the aquatic environment. High levels of these chemical contaminants are commonly found in sewage effluents discharged from conventional sewage treatment plants (STPs).  An interdisciplinary team led by the University of Hong Kong (HKU) has developed a novel wastewater treatment system that can effectively remove conventional pollutants, and recover valuable resources such as phosphorus and organic materials (i.e., carbon fibres and volatile organic acids).  This novel system combines chemically enhanced primary sedimentation (CEPS) of sewage with acidogenic fermentation of sludge in tandem (Image 1).  A series of laboratory experiments were conducted to prove that this novel system can effectively remove trace emerging chemical contaminants from wastewater and is more cost effective compared with conventional wastewater treatment systems.  The results of this study have been recently published in Water Research and Environment International. Moreover, in collaboration with the Nanshan Sewage Treatment Plant in Shenzhen, a pilot wastewater treatment system adopting the novel treatment process has been under construction in Shenzhen since 2019. It will come into operation and testing by this summer if the COVID-19 outbreak subsides (Image 2).   Background In the past few years, Professor Xiao-Yan Li of the Department of Civil Engineering who led the interdisciplinary research project, has been collaborating with Professor Kenneth Leung from HKU School of Biological Sciences and the Swire Institute of Marine Science to examine the levels and removal efficiencies of retinoids and oestrogenic EDCs from wastewater by the novel wastewater treatment process developed by the research team, and to compare that with the conventional STPs. The research team first examined the levels and removal efficiencies of retinoids and oestrogenic EDCs in Shatin, Stanley and Stonecutters Island STPs in Hong Kong by collecting wastewater and sludge samples from different stages of the treatment process, and analyzing the samples for retinoids and oestrogenic EDCs using liquid chromatography with tandem mass spectrometry (LC-MS/MS).  Secondly, a series of laboratory experiments were conducted using a small-scale pilot plant of the novel wastewater treatment process.  Samples of wastewater and sludge were taken for the chemical analysis using the protocols developed by Professor Leung’s team.   Key Findings The results indicated that the three STPs can only remove an average of 57% of retinoids (range: 41-82%) and an average of 54% of oestrogenic EDCs (range: 31-79%) from wastewater influents (this work was published in Environment International).   Using the novel treatment system operated under laboratory conditions, the CEPS process alone was demonstrated to be 16 - 19% more effective in removing retinoids and EDCs than the conventional STPs. 65 - 80% of retinoids and 72 – 73% of EDCs can be removed from the CEPS process (Image 3). After acidogenic fermentation of the CEPS sludge, 50 – 58% of retinoids and 47 – 50% of EDCs were further removed from the supernatants of sludge (this work has been recently published in Water Research).  Compared to the conventional STPs, the novel treatment system integrating CEPS with acidogenic fermentation of sludge is comparatively more efficient in removing emerging chemical contaminants from wastewater, and hence could reduce their environmental impacts. In terms of cost effectiveness, the CEPS process has been shown, by other studies, to be more cost-effective than the conventional wastewater treatment process. For instance, the cost of CEPS for wastewater treatment is less than a half of that of the secondary wastewater treatment (i.e., activated sludge process). On one hand, acidogenic fermentation of CEPS sludge can further reduce the treatment cost by recovering organic carbon and phosphate resources from the sludge as the harvested organic carbon and phosphate can be utilized to produce carbon fibers and fertilizers respectively. On the other hand, the acidogenic fermentation of CEPS sludge can provide additional removal of pollutants. The novel treatment process, therefore, offers win-win outcomes.   The Way Forward Professor Li, who led the study, said: “When the pilot wastewater treatment system in Shenzhen comes into operation and testing, we hope to demonstrate that this innovative technology will use less energy, generate cleaner effluent and recover more useful materials from the sludge.”   Professor Leung said, “We are very pleased to gather evidence for supporting our hypothesis that our novel sewage treatment system can effectively remove the emerging chemical contaminants. With the scaled-up pilot plant in Shenzhen, we will further investigate the removal efficiency of other classes of common pollutants by this novel treatment system.” Regarding its potential application in Hong Kong, Professor Li added, “Our system can be easily retrofitted onto the existing STPs in Hong Kong, like add-on units. For instance, the pilot system will be connected to the existing Nanshan STP in Shenzhen to test its performance. If successful, this will pave the way for advancing wastewater treatment in China and beyond.”  This innovative research is funded by Theme-based Research Scheme of Research Grants Council of the Hong Kong SAR.     The published articles: Zhou G.J., Lin L., Li X.Y., Leung K.M.Y. 2020. Removal of emerging contaminants from wastewater during chemically enhanced primary sedimentation and acidogenic sludge fermentation. Water Research 175: 115646. Link to the article: https://www.sciencedirect.com/science/article/pii/S0043135420301822   Zhou G.J., Li X.Y., Leung K.M.Y. 2019. Retinoids and oestrogenic endocrine disrupting chemicals in saline sewage treatment plants: Removal efficiencies and ecological risks to marine organisms. Environment International 127:103-113. Link to the article: https://www.sciencedirect.com/science/article/pii/S0160412018327570   Image 1: The novel wastewater treatment system developed by the Theme-based research team led by HKU: Fe-based CEPS with side-stream sludge acidogenesis in relation to the conventional wastewater treatment process. Image 2: The HKU research team’s pilot wastewater treatment plant adopting the novel treatment process under construction in Shenzhen, including the control system, a CEPS tank, an acidogenic fermenter and a moving bed biofilm reactor (MBBR) and carriers. Image 3: The novel wastewater treatment process and removal of emerging contaminants during this process. Image 4: Prof. X.Y. Li (Left) and Prof. Kenneth Leung (Right) taking this picture with the HKU Distinguished Visiting Professor John Giesy from Canada.  

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Pathway to HKU Science Series - Live lectures on ZOOM

Two live lectures were delivered via ZOOM by Dr George AKOM and Dr Evan PICKETT on March 27, 2020. Around 270 secondary school students joined the lectures, interacting and learnt from our teachers.  Missed the lectures? Here comes the recap and the video:  Lecture abstract: 1. Science, Technology and Us - by Dr George AKOM (Lecturer of Faculty of Science) Scientific principles are widely applied to address social issues around us. Scientific knowledge, therefore, is important not only to scientists but to the community. In this talk, we will examine a common compound (chemical) and try to understand how the science behind a common reaction (behaviour) of this compound can be applied to affect our lives in a dramatic way.  2. Animal Voices: What can we learn when we listen to nature? - by Dr Evan PICKETT (Lecturer of Faculty of Science) Animals make sounds for a variety of reasons: to communicate, to warn family of nearby predators, to attract mates. In this talk, we will explore the world of animal communication, what we learn from this chatter and how new technologies allows us to better understand our animal cousins.    

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Professor Che Chi Ming receives First Class Award of 2019 Shenzhen Science and Technology Prize from the Shenzhen Science and Technology Innovation Commission (SZSTI)

HKU chemical scientist Professor Che Chi Ming receives First Class Award of 2019 Shenzhen Science and Technology Prize

Professor Che Chi Ming Professor Che Chi Ming, Chair Professor and Zhou Guangzhao Professorship in Natural Sciences at the Department of Chemistry of Faculty of Science, the University of Hong Kong (HKU) has received the First Class Award of 2019 Shenzhen Science and Technology Prize from the Shenzhen Science and Technology Innovation Commission (SZSTIC). Professor Che specialises in synthesis of inorganic and organic chemistry, inorganic and metal organic photochemistry, photocatalysis and bioinorganic medicine, and has significant achievements in the studies of high-valent metal ligand multiple bond complex, inorganic and metal organic light emitting materials, photo-induced electrons and atom transfer reaction, as well as asymmetric olefin epoxidation. Professor Che thanks his research team members including Dr Cheng Gang, Dr To Wai Pong, Dr Lok Chun Nam and Dr Zou Taotao for their dedicated hard work to make the research a success. Professor Che has made innovative discoveries in inorganic photochemistry, electron transfer in multinuclear compounds and atom transfer chemistry. In particular, his outstanding contribution to the study in reactive metal-ligand multiple bonded complexes won him the First Class prize of the State Natural Science Award in 2007. He is the first Hong Kong scientist to have received the honour. The Shenzhen Science and Technology Prize was established in accordance with the Shenzhen Science and Technology Prize Incentives and related implementing rules. It is seen as the important window for the scientific and technological development in Shenzhen, which provides the essential motivation for the realisation of innovative breakthroughs in the city. Professor Che is the first HKU scholar to receive the award. Professor Che was elected to the Chinese Academy of Sciences as academician in 1995, the US National Academy of Sciences as foreign associate in 2013, the Hong Kong Academy of Sciences as founding member and vice president in 2015. Professor Che is now the Director of the Synthetic Chemistry State Key Laboratory, HKU-CAS Joint Laboratory on New Materials and Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis. He also serves the editorial board for Chemical Review and other internationally recognised academic journals.

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With elevated temperatures during a marine heatwave this cardinalfish species (Cheilodipterus quinquelineatus) shows the least changes in gene expression and appears to be more tolerant.

HKU marine biologist and international team unveil impacts of heatwave on reef fishes

A coral bommie filled with a variety of coral reef fish species with differential effects with increased sea temperatures during marine heatwaves. The marine heatwave of 2016 was one of longest and hottest thermal anomalies recorded on the Great Barrier Reef in Australia, influencing multiple species of marine ectotherms, including coral reef fishes. Dr Celia Schunter from School of Biological Sciences and the Swire Institute of Marine Science (SWIMS), The University of Hong Kong (HKU) and a team of international scientists conducted a study attempting to understand the molecular response of five species to the 2016 heatwave conditions that killed a third of the Great Barrier Reef corals. This is the world-first study tracking how wild fish populations respond to a severe marine heatwave. The results of the study were published in the journal Science Advances.  Marine heatwaves (MHWs) are elevated extreme temperatures in the oceans for an extended period of time, similar to an atmospheric heatwave. These elevated temperatures can have a significant impact on marine life, possibly pushing the thermal limits of many organisms. With the frequency and intensity of heatwaves predicted to increase in the future, this could have greater impacts on the performance of ectotherms, when compared to slight thermal increments over years or decades.  “To understand the challenges fish face under such conditions we used a molecular approach to evaluate how acute warming events directly affect reef fish communities in nature,” said Dr Celia Schunter. “We chose to work with five different species which are commonly found on the reef to be able to understand differences in reactions among fish species with different life histories to get a broader overview of the reaction and impact.”  “Our study shows that reef fishes are directly affected by heatwaves, but their responses vary greatly among species,” said co-author Associate Professor Jodie Rummer from the ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE at JCU).  Dr Rummer was part of the international team that studied changes in the expression of thousands of different genes in five species of coral reef fish, collected at different points before, during and after the 2016 heatwave.  “Changes in gene expression can tell us how an animal responds physiologically to an environmental shock, such as a heatwave,” said Dr Celia Schunter from HKU School of Biological Sciences and SWIMS, one of the lead authors in the study. “We measured RNA levels in livers in the fish. This can control when proteins are made and in what amount, and these proteins dictate how the cells of the body function. We saw many genes change expression levels across the timepoints of a heatwave revealing important functions such as cellular stress response and changes in metabolic functions.”   Through these genetic analyses, the team identified species-specific physiological responses to the heightened temperatures. “Fast water warming causes an increase of the metabolic demands in fishes, which are similar to what happens to an athlete doing intense exercises. When water temperature increases, fishes have a higher demand for energy and oxygen, which leaves a signal that is measurable with genetic techniques. This higher energy demand at warming can affect their reproduction, swimming and development, and that is why it is important to understand the response to warming.” said Dr Moisés A Bernal, co-author of the study from Auburn University.  Interestingly, “these patterns of gene expression also changed with the duration of the heatwave,” said Dr Rummer. “This suggests that the physiological mechanisms the fish use to cope with the warmer waters changed as the heatwave progressed. The results suggest fish populations are influenced by both the intensity of a heatwave and how long it lasts.” This signals potential long-term consequences for the health of fish populations as extreme heat events increase in frequency, duration and magnitude under human-induced climate change. At a species level, Dr Rummer says the responses varied in intensity. Some fish struggled less than others. “The spiny damselfish responded strongly to the warmer conditions, with changes in the expression of thousands of genes, suggesting it is particularly sensitive to heatwaves. Other species appear to be more tolerant, with fewer changes in gene expression.” said Dr Rummer. Two of the five studies species studied can also be found in waters around Hong Kong and Southern China as well as many more closely related fish species providing also some context for possible effects for waters around Hong Kong.  The study provides a possible approach for predicting which fish species are most at risk under repeated heatwave conditions, said another co-author Professor Timothy Ravasi, from the Marine Climate Change Unit at the Okinawa Institute of Science and Technology Graduate University (OIST). “This has ramifications for policy makers and for the fishing industry, because not all species will be equally affected. We need to screen a large number of species to predict which will be sensitive and which will be more tolerant to warming waters and heatwaves.” “Over time, the fish may adapt to rising temperatures, or even migrate to cooler waters,” Professor Ravasi said.  “But these heatwaves are happening now, and it’s necessary to understand and consider the immediate consequences.” In 2015 the South China Sea experienced a heatwave of a similar magnitude than the heatwave on the Great Barrier Reef studied here. The coastal waters of Hong Kong and the South China Sea are predicted to experience more frequent and intense marine heatwave events as seen on the global scale. It is now clear that these extreme events can have far-reaching effects on marine fishes, but also economic implications on aquaculture and fishing industries. Dr Celia Schunter urges the need for more research into the impacts of such events in the marine waters of Hong Kong to avert the potential collapse in the marine ecosystem and the industries relying on it. The paper: ‘Species-specific molecular responses of wild coral reef fishes during a marine heatwave.’ in Science Advances by Moisés A Bernal, Celia Schunter, Robert Lehmann, Damien J Lightfoot, Bridie J M Allan, Heather D Veilleux, Jodie L Rummer, Philip L Munday and Timothy Ravasi. Link of journal paper: https://advances.sciencemag.org/content/6/12/eaay3423 For more information about Dr Celia Schunter’s research, please visit: www.celiaschunter.com/

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HKU scientists find high concentrations of toxic phenyltin compounds in local Chinese white dolphins and finless porpoises

For years Professor Kenneth Leung Mei Yee from the HKU School of Biological Sciences and the Swire Institute of Marine Science and his research team, have been dedicated to the monitoring of toxic substances tribuyltin (TBT) and triphenyltin (TPT) compounds in our marine environment. Globally, organotin compounds such as tribuyltin (TBT) and triphenyltin (TPT) have been widely used as antifouling agents on ship hulls and submerged mariculture facilities over the past decades. Hence, they are often detected in seawater, sediment and biota samples collected from coastal marine environments of urbanised coastal cities worldwide. At very low concentrations, these compounds can cause endocrine disruption or even death in marine organisms. The International Maritime Organisation (IMO) of the United Nations has implemented a global ban on the use of organotin compounds on the hull of sea-going vessels since 2008. Together with their collaborators, Professor Leung's research team discovered that despite a decline of TBT concentration in our marine environment in recent years, the levels of TPT contamination remained serious with an increasing trend. In addition to TPT contamination in seafood, the team's recent research has also confirmed the occurrence of biomagnification of TPT compounds along the marine food chain, resulting in very high concentrations of TPT in two top predators, the Chinese white dolphin and the finless porpoises. This is the first study in the world to confirm the trophic magnification of TPT in food webs of cetacean species, and the findings were recently published in Environment International. Background TBT and TPT are highly toxic biocides which can cause growth inhibition to marine algae and mortality to many marine invertebrates and fishes at 1-50 μg/L*. At very low concentrations (1-10 ng/L**), these compounds can cause endocrine disruption in marine organisms such as growth retardation and shell thickening in oysters, and abnormal development of male sex organs on females of gastropods. TBT and TPT accumulate along the food chain in larger organisms such as fish, and may have an adverse effect on health when consumed by humans. Professor Kenneth Leung and his research team have been monitoring organotin pollution in the marine environment of Hong Kong since 2004. They discovered that TPT contamination remained serious with an increasing trend. TPT had been found in our seafood and in some case, their concentrations (e.g. those in tonguefishes) exceeded the food safety limit for human consumption. In 2017, the Government of the Hong Kong Special Administrative Region finally established a new legislation (Cap. 413, section 3) to support the IMO's global ban of using organotin compounds on vessels, and enhance the control of their release. Methodology In order to fully understand the extent of the contamination, Professor Leung and his team have recently completed a follow-up research in collaboration with Xiamen University and the State Key Laboratory of Pokfulam Road, Hong Kong Tel: (852) 3917 2683 Fax: (852) 2858 4620 E-mail: science@hku.hk Website: https://www.scifac.hku.hk/ Marine Pollution, to investigate the extent of TPT contamination in marine food webs in Hong Kong, and verify whether TPT and its degradation products (i.e., mono- and di-phenyltin; MPT and DPT) can be biomagnified through the food chain, leading to very high concentrations in local Chinese white dolphins (Sousa chinensis) and finless porpoises (Neophocaena phocaenoides). The Chinese white dolphins prefer the inner estuary of the Pearl River Delta, while the porpoises have a greater home range from the southwest to the southeast waters of Hong Kong. Between 2015 and 2017, the study team obtained samples of stranded dolphins and porpoises from the Ocean Park Conservation Fund Hong Kong and collected samples of marine molluscs, crustaceans and fishes from waters at the northwest (i.e., inner estuary) and southwest (i.e., outer estuary) of Lantau Island, respectively. Muscle tissues of all biota samples were analysed for MPT, DPT and TPT using gas chromatography-mass spectrometry, and used for determination of trophic levels using a stable isotope ratio mass spectrometer. Research findings Research findings showed that TPT was the predominant phenyltin compound in the marine mammals, indicating that contamination is an on-going issue. High concentrations of TPT were recorded in the muscle tissue of the Chinese white dolphins and the finless porpoises, with an average of 1,893.8 ng/g w. w. and 1,477.6 ng/g w. w. recorded respectively, even higher than the highest concentration of TPT ever reported in marine mammals the false killer whale worldwide (the false killer whale in Japan with 649 ng/g w. w.[1]). The highest concentration of TPT detected in an adult Chinese white dolphin in this study (3,476.6 ng/g w. w.) was five times higher than that of the false killer whale. At elevated concentrations, TPT can lead to sublethal adverse effects to the immune, nervous, cardiovascular and reproductive systems of mammals, resulting in a negative impact on the population fitness of these local dolphins and porpoises in the Pearl River Delta. Alarmingly, this study also found that the highest TPT concentration in a juvenile finless porpoise (3,455.6 ng/g w. w.) was ten times higher than the highest value (310 ng/g w. w.) recorded in the same species collected from Hong Kong in 2003[2], indicating a worsening situation of TPT contamination. Based on the results of stable isotope and chemical analyses, tissue concentrations of both DPT and TPT significantly increased with increasing trophic level of marine organisms in the food web of the Chinese white dolphins (i.e., inner estuary) while only TPT tissue concentration showed a positive relationship with the trophic level of the biota in the food web of the finless porpoises. For the Chinese white dolphins, trophic magnification factors (TMF) of DPT and TPT were found to be 6.03-11.48 and 2.45-3.39, respectively. For the finless porpoises, the TMF of TPT was found to be 2.51-3.47. When a TMF is greater than 1, it indicates that the chemical compound can be biomagnified through the marine food chain. The results of the study suggest that high trophic organisms including humans are likely to be vulnerable to the exposure of DPT and TPT compounds via dietary intake due to the high trophic magnification potential of these chemicals. Therefore, environmental and human health risks of these compounds should be assessed with consideration of their biomagnification potentials along the food chain. Regarding ways to reduce the health risk of TPT exposure, Professor Leung said, "The public should avoid and minimise the consumption of very large fishes such as sharks and Reeve's croakers, and also benthic fish species such as the flathead and tongue sole fishes, as they probably contain high concentrations of TPT and other persistent organic pollutants in their tissues. Instead, they can consume crustaceans (e.g. shrimps and crabs), shellfishes (e.g. mussels, clams and oysters), and small fishes as an effective way to reduce the intake of TPT and other chemical contaminants." Dr James Lam Chung Wah, an environmental toxicologist and Assistant Professor at the Department of Science and Environmental Studies of the Education University of Hong Kong, who was not involved in the study, commented, "This interesting and impactful study led by HKU provided solid evidence of such a significant biomagnification of TPT along the marine food chain of marine mammals. Their results also highlight the greater impact of TPT on top predators in the sea and in humans through seafood consumption." He also added, "To improve the current situation of organotin contamination, we must reduce their use and release at the source. Around the world, every government needs to play a part in strengthening the regulation and control of the use of toxic chemicals (like TPT compounds) in order to minimise their release into the environment." *1 μg/L is like putting 2.5 g of sugar grains in a standard Olympic-size swimming pool (2,500,000L) **1 ng/L is like putting 4 tiny grains (a grain = 0.00065 g) of sugar in a standard Olympic-size swimming pool   Cited References: [1] Harino et al. 2007. Accumulation of organotin compounds in tissues and organs of stranded whales along the coasts of Thailand. Arch. Environ. Contam. Toxicol. 53: 119-125. [2] Nakayama et al. 2009. Temporal and spatial trends of organotin contamination in the livers of finless porpoises (Neophocaena phocaenoides) and their association with parasitic infection status. Sci. Total Environ. 407: 6173-6178.   The paper: “Occurrence and trophic magnification profile of triphenyltin compounds in marine mammals and their corresponding food webs”, Environment International (link to the article: https://www.sciencedirect.com/science/article/pii/S0160412019332635)

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