top of page

The Global Estuaries Monitoring Programme

Occurrence and environmental risks of pharmaceuticals and other emerging chemical contaminants of concern in the major estuaries around the world.

Study Background

At present, over 100,000 chemical substances are being used in our daily life and in industries.  Among which, 4,000 pharmaceuticals are currently in use to prevent and treat human and animal diseases.  Many of these chemicals will eventually be released into the estuaries through pathways such as rivers, surface runoff and partially treated effluents discharged from wastewater treatment plants. Globally, there is a lack of information available for the occurrence and environmental risks of various chemical contaminants in urbanised estuaries, especially those in Africa and South America, and in some coastal areas in Southeast Asia and Oceania. Hence, the GEM Programme will develop standardised methods to sample, extract and quantify the priority chemical contaminants in seawater samples collected from major urbanised estuaries worldwide, enabling scientifically sound global comparison of the results among various estuaries.

GEM Factsheet.jpg

Study Objectives


Establish a global monitoring network for chemical contaminants in major estuaries in the world. Researchers will receive training on how to collect environmental samples, prepare the samples and conduct the chemical analyses via online and/or face-to-face training sessions. Regular meetings will be held to update the research progress and share the findings, while forums on how to achieve cleaner estuaries will be organised to make recommendations to United Nations and individual governments.

Capacity Building


The standardisation of methods for sampling, sample treatments and analyses will allow a fair and scientifically sound comparison of the results across different study sites worldwide.

Research Methods


Pollution hot spots and clean estuaries will be identified based on the results. Socioeconomic and policy analyses will be made to determine factors, drivers and best practices that can concomitantly lead to pollution reduction. National and regional governments could make reference to the recommendations for reducing the risks of the contaminants.

Promote Best Practices in Pollution Control


All partners in the GEM programme will be able to share the information and data generated from the programme via this website where members can upload and download the information (like map indicating the sampling sites) and data. The results will be disseminated to corresponding governments and United Nations.

Data Sharing


The first phase of the project focuses on pharmaceutical residues in estuaries. Once the first phase is set up and running smoothly under a global network, members and end-users of our results (e.g. policy makers and environmental authorities, fishermen community, and other concern groups) will co-design research strategies for the next phase. 

Research Strategies


The results of this global effort will help reveal the latest status of chemical contaminations in major estuaries around the world, identify pollution hotspots, and develop pollution strategies by following best practices and tiered mitigation measures via socioeconomic and policy analyses.

Reveal Estuaries
Health Status


Figure 1. Schematic diagram to summarise the main components and tasks of the Global Estuaries Monitoring Programme as well as its alignment of the outcomes for promoting cleaner, safer and transparent estuaries.

Study Timeline

First Phase of GEM Programme

Focus on method development and study of pharmaceutical residues in estuaries.

July 2021-June 2023: 

Sampling and analysis method development and global estuary monitoring network establishment

July 2023-December 2024: 

Water samples will be collected from major urbanised estuaries globally during dry season.

From 2025: 

Chemical analyses, data analyses and report writing for the global monitoring results will be completed to conclude the first phase of the GEM Programme. 

Second Phase of GEM Programme

In 2025:

Partners will co-decide on the new target pollutants (e.g. emerging chemicals of concern, antibiotic resistant genes, micro-plastics, pathogens), co-design the future global experiments, and co-solicit external funding for the next phases of the GEM Programme. 

Lead Institution: Federal Rural University of Pernambuco – Brazil

Contact Person: Caroline Miranda Biondi

Email Address:

Lead Institution: School of Aquatic Sciences and Fisheries Technology, University of Dar es Salaam, Tanzania

Contact Person: Dr. Blandina Lugendo

Email Address:;

Lead Institution: Center for Human-Environmental Research

Contact Person: Grant S. McCall

Email Address:

bottom of page