Global Estuaries Monitoring Programme: Combatting Chemical Pollution

By Kenneth Mei-Yee Leung 20 September, 2022

We chat with Dr. Leung, Chair Professor at City University HK, to learn how his GEM project is closing the research gap on the pollution in global estuaries. Plus, he shares how some HK rivers rank on antibiotic pollution

GEM extends the GMP project from rivers to estuaries, aims to standardise robust & affordable sampling & pollutant analyses – incl. pharma & metals; now in 30 countries
There cannot be healthy rivers or oceans without healthy estuaries; upstream countries matter - need intergovt approach; 2 HK rivers rank 38th & 55th most polluted out of 258
Global warming could cause chemical concentrations in marine environ to rise 3x; need to measure to manage but also need solutions, like proper collection & public education
Kenneth Mei-Yee Leung
Author: Kenneth Mei-Yee Leung
Dr. Kenneth Mei-Yee Leung is Chair Professor of Environmental Toxicology and Chemistry, and Acting Head at Department of Chemistry in City University of Hong Kong, where he also serves as the Director of the State Key Laboratory of Marine Pollution. His research interests encompass marine pollution, ecotoxicology, marine ecology, biodiversity conservation, and ecological restoration using eco-engineering. In 2017, he was awarded the 19th Biwako Prize for Ecology by the Ecological Society of Japan, and conferred as a Fellow of the Society of Environmental Toxicology and Chemistry (SETAC). He was elected a Fellow of the Royal Society of Chemistry and a Fellow of the Royal Society of Biology in May and July 2022, respectively for his outstanding achievements in research, education and community services. He is actively supporting the Hong Kong SAR Government in environmental management and biodiversity conservation through serving on various advisory committees (e.g. the Chairman of the Advisory Council on Food and Environmental Hygiene, the Chairman of the Lantau Conservation Fund Advisory Committee, and a Member of the Advisory Council on the Environment).
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The Global Estuaries Monitoring (GEM) Programme is co-designed by partners and stakeholders with a view to developing a global network to monitor environmental contaminants (e.g. pharmaceutical residues, emerging pollutants of concern, micro-plastics, pathogens etc.) in major urbanised estuaries worldwide. The Programme will develop standard sampling and analysis methods with training opportunities to build capacity for global estuaries monitoring. With about 100 countries expected to join the Programme, its results will reveal the pollution situation around the globe, identify the estuaries that require attention and improvement, recommend priority contaminants for control, and promote best practices to combat the pollution problems and thereby creating cleaner estuaries.

CWR: Thank you for speaking with us Professor Kenneth Leung and congratulations on getting the UN endorsement on your programme, the Global Estuaries Monitoring (GEM). To kick off, could you give us a brief background of the project?

Professor Kenneth Leung (KL): The GEM programme was inspired by the Global Monitoring of Pharmaceuticals (GMP) Project which was led by Professor Alistair Boxall at York University in the UK. The GMP Project was able to motivate and mobilise 127 researchers from 104 countries/regions to collect water samples from 258 rivers around the world using the same standardised method and sampling kit. In total, there were 1053 sampling locations. All samples were returned to York University for chemical analysis for 61 common pharmaceuticals using a standardised method which allowed a global comparison of the results for the first time.

The Global Monitoring of Pharmaceuticals (GMP) Project collected 1,053 samples from rivers around the world…

The beauty of this GMP Project was that the standardised yet simple method allowed researchers from developing nations to join in this global monitoring and enabled the monitoring of many rivers that had never been studied before. The results have been recently published in PNAS. The results not only highlighted the rivers with the highest contamination of pharmaceuticals and the most commonly detected medicines, but also revealed the drivers for causing such pollution problems. For example, rivers in the countries of lower-middle income were most polluted with medicines because people there could afford to purchase drugs, and there no adequate waste and wastewater collection, and treatment facilities.

Also, there were limited regulations on drug prescription in most of these countries. The level of contamination was also associated ages in the population and poverty. The scientific information was highly valuable to identify the global pressing problem of pharmaceutical pollution, in particular the common contamination of antibiotics in the world’s rivers, and to formulate solution to the problem via stakeholders engagement.

…The Global Estuaries Monitoring (GEM) project extends the GMP from rivers to estuaries…

To extend the GMP Project from rivers to estuaries, we have partnered with York University in the UK (the GMP Project), the World Harbour Project in Australia (the Sydney Institute of Marine Science), Baylor University in the US, Xiamen University (the State Key Laboratory of Marine Environmental Science) and China’s National Marine Environmental Monitoring Centre. We submitted our proposal of the GEM Programme to UNESCO-IOC in December 2020 which was then selected as one of the Action Programmes under the UN Decade of Ocean Science for Sustainable Development (2021-2030) on the world’s ocean day in June 2021.

The GEM first aims to develop standard and robust yet affordable methods for sampling and pollutant analyses, as such researchers in developing nations can also join this global effort and allow the team to monitor urbanised estuaries which have never been studied before or have been understudied. The target pollutants will not only cover pharmaceuticals like in the GMP Project, but also include contaminants of emerging concerns, microplastics, metals, pathogens and antibiotics resistant genes etc.

…aims to standardise robust & affordable methods for sampling & pollutant analyses – incl. pharmaceuticals & metals…

…currently GEM is covering 30 countries

All partners will jointly co-design the GEM Programme. Secondly, we will organise regular forums via internet to share the results, and engage stakeholders to co-develop solutions to reduce the pollution and recommend practical ways to improve water quality for different nations, ranging from education to policy and technology for pollution control. Our GEM Programme echoes the motto of UN Decade of Ocean Science “The Science we need for the ocean we want”. Eventually, we hope that our science and translational effort will help make the estuaries and ocean cleaner and safer for all.

We have recently launched the GEM Programme and have recruited 46 partners from six continents, covering 43 coastal cities in 30 countries. We are hoping to have 100 partners by the end of 2022. The first phrase of the project will focus on monitoring of pharmaceuticals and metals via collection of oysters, sediments and the use of passive samplers (e.g. Artificial Mussels).

During the past year, we have found that a large volume of seawater samples will be required for analysing various pharmaceuticals, but the shipping a large volume of seawater samples by courier service will be costly and may not be feasible. Hence, we have been shifting from sampling seawater to sampling biota and sediment samples. We are currently working on the establishment of the standard methods.

Click here for an overview of the GEM Programme.

CWR: It’s great to hear that the first phase of the project programme was launched last month. Could you elaborate on how estuaries play an important role in a holistic pollutant management, A.K.A source-to-sea or mountains-to-oceans management?

Prof. KL: Chemical contaminants often go along with the river discharge and surface runoff, and they will pass through the estuary before entering into the ocean. It is also common that an estuary will receive contaminated freshwater from multiple rivers. Although at an estuary, seawater may dilute the chemical contaminants from rivers, the level of contaminants in seawater, sediment and biota in the estuaries can indicate the current status of pollution and the health of the coastal marine ecosystem. Healthy oceans cannot be achieved without healthy estuaries.

Healthy oceans cannot be achieved without healthy estuaries

To control and minimize marine pollution, source-to-sea management is prerequisite. After the completion of the study on monitoring the pollution status, it is possible for the GEM Programme to launch a further study on source appointment of pollutants (i.e., figuring out the source of the pollutants and then suggesting ways for their control at the source).

CWR: A key chemical pollutants is pharmaceuticals. Could you share some of the key findings from the study you participated earlier this year on pharmaceutical pollutants found in Hong Kong rivers?

Prof. KL: As most of pharmaceuticals could not be totally assimilated by humans, they would be end up in human excreta (urine and faeces) and discharged into the sewage system.

However, many of pharmaceuticals in wastewater could not be fully removed by sewage treatment process, and thus they occur in treated sewage effluent and contaminate the receiving water body. As part of the GMP Project, our team had collected river water samples from Kai Tak River and Lam Tsuen Rive for analysis of 61 pharmaceuticals.

Kai Tak river & Lam Tsuen river – 38th & 55th most polluted out of 258 global rivers…

…and ranked 20th & 74th most polluted with antibiotics

Kai Tak River and Lam Tsuen River were ranked as the top 38th and 55th most polluted rivers out of the 258 rivers around the globe, indicating they were moderately contaminated with pharmaceuticals. However, alarmingly, 34 kinds of pharmaceuticals were detected in Kai Tak River, which was the highest record in this GMP study. The most common pharmaceuticals the two rivers included caffeine, cetirizine, clarithromycin, fexofenadine, gabapentin, metformin and sitagliptin; they are antibiotics, anticonvulsants, antihistamines, antihyperglycemics and stimulants, respectively.

Kai Tak River and Lam Tsuen River were ranked as the top 20th and 74th most polluted rivers with antibiotics. Special attention should be paid to ciprofloxacin and clarithromycin in Kai Tak River, which exceeded their safety thresholds and had a high risk in inducing antimicrobial resistance.

CWR: Are there any implications for Asia’s rivers considering river’s transboundary nature?

Prof. KL: In the GMP Project, the ten most polluted rivers with pharmaceuticals were located in: Bolivia, Pakistan, Tunisia, Ethiopia, India, Congo, Kenya, Armenia, Israel and Costa Rica. In Asia, relatively highly polluted rivers included those in Pakistan, India, Malaysia and China (Guangzhou and Hong Kong).

Upstream countries will have an impact…

…an intergovernmental collaboration is required to achieve a healthy waterways

Apart from pharmaceuticals, other legacy pollutants and contaminants of emerging concerns will also present in those polluted rivers, and elevated levels of such chemical contaminants may pose ecological risk to the coastal marine ecosystem, and health risk to humans who may expose to the chemicals via seafood consumption.

For some river with the transboundary nature (e.g. Mekong River), the contaminated discharge from a country in the upstream will have an impact to a country in the downstream. Hence, an intergovernmental collaboration is required to achieve a healthy waterway including the estuary. In general, a better green infrastructure for collection and treatment of waste and wastewater is urgently needed in developing nations in Asia.

CWR: Next up, in the recent report ‘The Invisible Wave’ by the Economist Impact and the Nippon Foundation, you mentioned about how chemical pollution could be worsened by the effects of climate change. Why is this? 

Prof. KL: Under global warming, ambient temperature will increase. Increasing temperature will accelerate the chemical reaction and promote the release of chemical contaminants into the ecosystem via various physicochemical processes (e.g. evaporation, precipitation and infiltration). It was estimated by modelling projections that global warming could cause chemical concentrations in marine environments to rise as much as three-fold.

“… global warming could cause chemical concentrations in marine environments to rise as much as three-fold”

We have done some experiments and concluded that temperature remains the main driver when it comes to changing chemical toxicity, and also by means of changing the chemical properties of the pollutants, and how organisms respond to multiple stressors. In the marine environment, there is evidence that temperature shifts alter the metabolism of marine organisms. For instance, the thermal performance curve theory explains the performance of fish in terms of aspects like growth and reproduction rates.

Performance climbs as the temperature rises until the fish reach their optimal temperature — beyond which their performance drops fast. So some marine organisms perform far worse at temperatures that are much higher or much lower than the optimum. Adding certain chemicals to the water further depresses this curve, which means their performance declines even faster at those higher temperatures. Based on that prediction, many species may suffer more in the presence of chemical stressors under global warming [refer to P.75-76 in “The Invisible Wave”].

CWR: Lastly, what are the solutions would you like to see fast-tracked? What do you want to see happen in the next couple, five, ten years?

Prof. KL: In a short-term, we will focus on capacity building among scientists from coastal cities worldwide. We will start some global projects together (e.g., monitoring pharmaceuticals, microplastics, metals) and achieve a common goal together. We will share the results together with environmental authorities and stakeholders, and recommend some practical and tangible solutions to reduce the pollution.

We will then get together to formulate the next phase of the GEM project, and expand the project to cover other kinds of pollutants which may include chemicals of emerging concern, pathogens and antibiotic resistant genes.

First need to measure to know what we need to manage…

New technologies for sampling various target pollutants may be developed and advanced. As an old saying “You can only manage what you measure”. To manage pollution in estuaries, we first need to reveal the current pollution situation, and identify the major pollutants of concern and the problematic estuaries. With such scientific data, scientists, environmental authorities, and stakeholders will discuss the way forward and come up with tangible solutions for minimizing the pollution.

…one solution can be centralizing the collection of expired drugs for proper treatment

The solution could be simple as centralizing the collection of expired drugs for proper treatment so as to reduce their direct disposal into the waterway (e.g. via the toilet), and educating the general public about the practices of the 3R (reduce, reuse and recycle). Science and education are equally important in improvement of environmental quality.

Once estuaries with high pollution are identified, there are needs for improvement in these impacted coastal cities. With the scientific data, we shall work with their governments and call for assistance from organisations such as The World Bank and philanthropies to establish needed green infrastructure for collection and treatment of waste and wastewater. By the end of our GEM Programme in 2030, we do hope to see some positive changes in pollution reduction (via reduction and control at the source, and treatment) that will lead to cleaner and safer estuaries.

Further readings

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