EVENT: On September 16th, a high-level event will be held to mark the International Day of Science, Technology and Innovation for the South 2026, the United Nations General Assembly invites member states, specialized agencies, international organizations, academia, civil society, the private sector, and other stakeholders to observe this International Day. It encourages them to present "initiatives, including cooperation projects in the areas of science, technology and innovation that contribute to the development of developing countries in those fields."The celebration represents an important step in reaffirming our commitment of leaving no one behind. It underscores that advancing science, technology, and innovation is essential not only for achieving the Sustainable Development Goals (SDGs) but also creating a fairer, more participatory, and inclusive world. Register to participate!
PUBLICATIONS: Mapping South-South Cooperation in Science, Technology and Innovation for Theory and Practice. Science, technology, and innovation (STI) are key to economic and social development, yet the capacity for scientific innovation remains unequally distributed across the globe. Working from the perspective of access, equity and inclusion (AEI), the present study analyses the state of STI in the Global South and the potential challenges associated with creating an effective linkage between STI and South-South Cooperation (SSC). Our objectives are to assess the state of STI in the Global South from an analytical perspective, determine its importance, identify the challenges and issues faced by stakeholders as they strengthen their STI architecture, and generate a template for a database and inventory of SSC-STI linkage initiatives so as to track STI collaboration through SSC. This study offers insights into the nature of the gap that exists in STI infrastructure between the industrialized and the developing worlds, particularly in countries considered as the least developed, through the analysis of a number of the standardized indicators used to quantify achievement in knowledge and technology. It further considers a number of instances of cooperation between countries in the Global South through sharing technology and attempts to identify the existing cooperation patterns. The patterns thus identified form the basis for a template that may be used to document the kinds and variations in technology sharing among partner countries in the Global South that can serve as reference points for further collaboration and sharing. The template will also help to create an inventory of technologies that could potentially be improved or modified to meet the specific requirements of interested partners. The document offers policy recommendations that may enhance STI architecture in the Global South through SSC. To read the full publication; Download the South-South Ideas Paper.
According to a recent analysis of science and technology policy trends, OECD member countries are experiencing changes in the science, technology, and innovation environment, with R&D investment as a percentage of GDP stagnating at around 2.7%. The share of the energy sector in national government R&D budgets was found to have significantly expanded, increasing approximately 2.3-fold compared to 2015. The growth in the share of international co-authored papers from the United States and the European Union (EU) has slowed since 2018, while the number of countries introducing research security-related systems has increased to over 40. The OECD diagnosed the recent trend as "a situation of increasing policy complexity due to intensifying technological competition and expanding geopolitical fragmentation," emphasizing that countries must secure policy efficiency and agility even with limited resources. It stated that in a rapidly changing environment, countries must create synergy between conflicting science and technology policies and enhance efficiency by strengthening linkages between them. The OECD observed that the convergence of advanced technologies such as synthetic biology, neurotechnology, quantum technology, and space-based Earth observation is fundamentally changing the innovation process and policy demands. It predicted that technological convergence will be a key factor in future global competitiveness. The report presented a three-pronged policy framework of "promote, protect, and project" and three principles of "proportionality, partnership, and precision" to balance scientific openness and economic security.
GET INVOLVED! Promote SSC and STI in developing countries and the least developed countries '
The future of Science, Technology, and Innovation (STI) in ASEAN just took a big leap forward. Officially adopted at the 21st ASEAN Ministerial Meeting on Science, Technology and Innovation (AMMSTI-21) in Indonesia, the APASTI 2026-2035 charts a shared vision for a sustainable, innovative, and resilient ASEAN. The document was developed through a consultative process with all ASEAN Member States and partners. The APASTI 2026–2035 will guide ASEAN’s STI cooperation over the next decade, strengthening regional capacity to innovate, collaborate, and respond to emerging global challenges.
FORUM: “Global action for a cooler planet” International Day for the Preservation of the Ozone layer 2026. This year's theme celebrates the Montreal Protocol and the transformative impact of its Kigali Amendment ten years after adoption. The Montreal Protocol has demonstrated that science based policy, universal participation, strong compliance, dedicated financing, and effective partnerships can deliver real and measurable results. Through these elements, the treaty has not only protected the ozone layer but also enabled countries and industries to transition to safer, more sustainable alternatives while supporting economic development. Building on this legacy, the Kigali Amendment has expanded the Protocol’s impact by driving the global phase down of HFCs—potent greenhouse gases—and accelerating the transition toward more efficient and sustainable cooling solutions. Over the past decade, Kigali has shown how development priorities can be achieved by promoting energy efficient technologies, strengthening industrial capacity, and supporting innovation across the cooling sector. Together, the Montreal Protocol and the Kigali Amendment demonstrate that cooling the planet is not only possible, but achievable when countries act collectively, industries innovate responsibly, and international partnerships turn commitments into action—delivering benefits for the climate, economies, and people worldwide. Follow the conversations with the hashtags: #16September, #OzoneDay, #MontrealProtocol, #HFCs, #KigaliAmendment, #Ozonelayer, #climatechange.
EVENTS: On September 16th, the UNEP Ozone Action and its partners will mark the International Day for the Preservation of the Ozone Layer 2026. On this thirty-ninth anniversary, we will remember how the Montreal Protocol ended one of the biggest threats ever to face humanity: the depletion of the ozone layer. This observance marks the 10th anniversary of the Kigali amendment. Participants will look to the future for deeper and faster action under the Montreal Protocol. Deeper and faster for the ozone layer but above all, for people, for climate and for the planet. Register to participate and watch the livestream!
Ten years ago, the world added a new chapter to one of its greatest
environmental success stories. Building on the Montreal Protocol, which put the
ozone layer on the path to recovery, nations adopted the Kigali Amendment to
tackle a new threat: hydrofluorocarbons (HFCs) – potent greenhouse gases used
for cooling.
This year’s theme, “Global action for a cooler planet”, highlights a defining
climate challenge. As temperatures rise and extreme heat becomes more
common, access to efficient cooling saves lives. We must meet that need fairly
and sustainably.
Fully implemented, the Kigali Amendment alone could avoid up to 0.5 degrees
Celsius of global warming by the end of the century – and twice as much when
paired with energy-efficient cooling. This is essential for health, food security,
livelihoods, and climate resilience.
On this World Ozone Day, I urge all countries to ratify and implement the
Kigali Amendment, accelerate the shift to sustainable cooling, and protect
people and planet.
As climate change drives global temperature rise towards exceeding 1.5 degrees C target of the Paris Agreement, the world is seeking solutions that deliver real results. So on World Ozone Day, we celebrate one such solution, the Montreal Protocol on substances that deplete the ozone layer. This agreement has put the ozone layer on a path to recovery, protecting millions of lives and vital ecosystems from harmful ultraviolet radiation. But the Montreal Protocol is doing much more than that. This year we mark the 10th anniversary of the protocol's Kgalli amendment. Under this amendment, countries are phasing down hydrofluorocarbons, powerful greenhouse gases widely used in cooling. If fully implemented, this could avoid up to half a degree Celsius of global warming by the end of the century. And if we combine this transition with energy efficient cooling, we could double these gains. So achieving these gains is crucial. Deadly and disruptive extreme heat is rising while billions of people lack access to safe and effective cooling. So we must close the cooling gap while keeping emissions down. This is why this year's theme, global action for a cooler planet, is so important. Sustainable cooling is not a luxury. It is essential for health, for development, and for climate stability. The amendment strives to extend access to sustainable cooling for every human being. But to unlock the full potential of the Kgalli amendment, we need universal ratification and full implementation. So on this World Ozone Day, I call on all countries that have not yet done so to ratify the Kaggali amendment without delay. And I call on all governments to accelerate its implementation. And I do call on industry to invest in climatefriendly energy efficient cooling solution because every fraction of a degree of global warming avoided matters and the Kegali amendment, if fully implemented, can deliver.
FORUM: "Raising Hands and Voices" International Day of Democracy 2026. This year celebration will highlight how deliberative democracy can foster greater agency and ownership by bringing diverse voices into decision-making.The strength of democracy lies in its ability to embrace and balance differences to serve society as a whole. Diversity is a source of resilience, adaptability and creativity. But it can also be exploited for political gain by polarising opinion and deepening divides. Socio-economic, gender, ethnic, generational and other inequalities fuel divisive rhetoric and trigger electoral choices which make democracies increasingly fragile. Follow the conversations with the hashtags: #InternationalDayofDemocracy, #15September, #DemocracyDay.
Today, on the International Day of Democracy, we face a world of deepening division. Conflicts are multiplying, trust is eroding, and the social contract between citizens and their governments is being undermined.
Democracy is more than elections. Democracy is a daily practice of ensuring human rights, the rule of law, and the meaningful participation of all people across civic and political life. It thrives through dialogue, collaboration, and working to understand different points of view — including civil society.
This year’s focus on deliberative democratic processes reminds us of the importance of bringing together people from across societies to enrich decision making, foster trust, and build more peaceful, inclusive, and resilient societies.
Having personally faced the challenges of restoring democracy in my own country, I know it must never be taken for granted. Each time we choose dialogue over division, and cooperation over confrontation, we strengthen democracy.
Today and every day, let us recommit to ensuring every voice counts, and that democracy delivers the peace, dignity and inclusion that every society needs and deserves.
FORUM: "Solidarity Rising: Global Alliance for Inclusive and Innovative Development." United Nations Day for South-South Cooperation 2026. Across the Global South – 134 countries that are home to 80 percent of the world’s population – solidarity is rising. Countries are increasingly turning to one another to exchange innovative ideas, expertise, and effective solutions. From renewable energy and digital innovation to public health and sustainable agriculture, successful approaches are being shared, adapted and scaled in ways that improve lives. What unites these efforts is the growing recognition that progress is strongest when knowledge, experience and opportunity are shared. This momentum is building against a difficult backdrop. For example, developing countries paid a record US$921 billion to service external debt in 2024, and UNCTAD estimates that 3.4 billion people now live in countries that spend more on interest payments than on health or education. Communities are confronting droughts, floods and extreme weather. Young people are seeking opportunities in a rapidly changing digital economy. Countries are striving to improve health care, education, energy access and economic growth while navigating increasing uncertainty. No country can solve these challenges alone. Yet there is reason for optimism. South-South trade alone reached US$7.2 trillion in 2025, from the 1995 baselineOf $0.5 trillion. Today, more than half of all exports from developing countries are destined for other developing economies, compared to just 38% three decades ago. Similarly, South-South investment has become an increasingly important force in the global economy. Since the 1990s, foreign direct investment (FDI) flows among developing countries have quadrupled, with their share of global FDI rising from just 9% to 32% in the period 2020– 2023. Today, the Global South generates more than 40% of global economic output, accounts for nearly half of worldmerchandise trade, and attracts over half of global investment inflows. These shifts and trends highlight the growing economic weight and influence of developing countries, as well as the growing economic interconnectedness of the Global South and its increasing role in shaping global trade patterns. Farmers are adapting techniques pioneered elsewhere to strengthen food security. Cities are applying lessons from peers to build safer and more resilient communities. Governments are drawing on experiences from other countries to initiate and/or expand access to renewable energy, improve public services and strengthen disaster preparedness. These exchanges are helping countries leapfrog traditional development pathways by drawing on proven successes. This is the essence of South-South and triangular cooperation: building on shared experiences to pave pathways of shared progress. The United Nations Day for South-South Cooperation celebrates this spirit of solidarity and collaboration. It recognizes that every country has something valuable to offer and that solutions emerge from every region of the world. It is about sharing ideas, building trust and learning from one another. This year’s theme, “Solidarity Rising: Global Alliance for Inclusive and Innovative Development”, reflects a simple reality: today’s challenges are shared, and so are the solutions. Across regions, countries are connecting expertise, innovation and experience to address common priorities. The theme reflects how collective actions and collaboration are shaping a more inclusive, resilient and sustainable future. This growing momentum is documented in the Global Report on South-South and Triangular Cooperation, which highlights how countries of the Global South are increasingly driving innovation, sharing solutions and forging new partnerships to address complex development challenges. The report points to a future in which South-South and triangular cooperation play an even greater role in accelerating sustainable development and strengthening international cooperation. A similar trend is evident across the current generation of United Nations Sustainable Development Cooperation Frameworks. Increasingly, South-South and triangular cooperation are being positioned not as stand-alone areas of work, but as strategic means of implementation for advancing nationally owned SDG priorities. Countries are using these approaches to mobilize expertise, strengthen institutional capacities, scale proven solutions and diversify partnerships. In several cases, Cooperation Frameworks identify stronger South-South and triangular cooperation networks and platforms as an important means of maintaining development progress amid growing geopolitical uncertainty and fragmentation. Recent international gatherings have also highlighted both the urgency of these challenges and the power of cooperation to address them. During the 22nd Session of the High-level Committee on South-South Cooperation, which drew more than 130 countries and stakeholders – the highest level of engagement in the Committee’s history – Member States reaffirmed the importance of countries working together to accelerate sustainable development and strengthen international solidarity. Discussions underscored the growing role of South-South and triangular cooperation in responding to emerging challenges and advancing shared development priorities. During the Dushanbe Water Conference, leaders and experts emphasized that water security is one of the defining challenges of our time. It is no longer solely an environmental issue, but a major socio-economic, peace and security priority directly linked to sustainable growth, inclusive prosperity, and resilience of countries and communities. Countries shared practical experiences on managing water resources, building resilience to water-related stresses and disasters, and strengthening cooperation across borders to protect communities, livelihoods and ecosystems. In Baku, at the World Urban Forum, governments, cities and partners explored how cooperation can help create more sustainable, inclusive and resilient communities across the rural-urban continuum, particularly in the rapidly urbanizing Global South. Discussions explored approaches to housing, infrastructure, climate resilience and urban planning, demonstrating the value of learning from one another’s experiences. The 2026 observance of the United Nations Day for South-South Cooperation will mark the launch of the Global Alliance for South-South and Triangular Cooperation, a new platform designed to connect countries seeking solutions with partners that can contribute expertise, experience and catalytic support. The Global Alliance will help transform shared knowledge into practical action by facilitating partnerships, strengthening collaboration and expanding opportunities to scale successful solutions. Supported by UNOSSC’s South-South Galaxy+, the Global Alliance will enable countries and partners to connect more easily, identify opportunities for cooperation and share experiences across regions and sectors. By bringing together governments, United Nations entities, development partners, financial institutions, academia, civil society and the private sector, the Global Alliance will strengthen collective action for sustainable development. As the international community looks ahead to important discussions on the future of South-South cooperation during the eighty-first session of the General Assembly, the United Nations Day and the launch of the Global Alliance for South-South and Triangular Cooperation arrive at a pivotal moment, not only to celebrate progress, but to set the course for what comes next. The message is unmistakable: solutions, expertise, and innovation are already at hand. Across the Global South, countries are leading the way by showcasing proven models of success. The task before us is to connect these solutions, strengthen partnerships and scale impact so that more people can benefit from the knowledge and experience that already exists. Rising solidarity provides an opportunity to transform shared challenges into shared progress. United Nations Day for South-South Cooperation 2026 is therefore more than a celebration. It is a call to action. It is an opportunity to strengthen partnerships, share solutions and reaffirm a simple principle that remains as important today as ever: when countries work together, everyone benefits. Join the Global Alliance for South-South and Triangular Cooperation. Together, we can move solutions further, faster. Follow the conversations with the hashtags: #12september, #SouthSouth, #TriangularCooperation, and #SouthSouthCooperation.
On the United Nations Day for South-South Cooperation, we celebrate the transformative power of partnership to accelerate sustainable development.
This year’s theme – “Solidarity Rising: Global Alliance for Inclusive and Innovative Development” – reminds us that countries across the Global South are creating and sharing solutions every day.
We have seen what South-South cooperation can achieve: from farmers adapting to a changing climate, to entrepreneurs expanding access to green energy, to health workers responding more rapidly to outbreaks.
The launch of the Global Alliance for South-South and Triangular Cooperation marks an exciting new chapter. Bringing together governments, development banks, academia and the private sector, it will help match national priorities with financing and expertise – connecting ideas to investment, and ambition to action.
As we observe this important day, let us ensure that solutions created anywhere can improve lives everywhere. Let’s come together across borders for equality, prosperity and peace.
Agenda programme of the United Nations Day for South-South Cooperation 2026.
11 September 2026 | 10:00am - 1:00pm United Nations Headquarters
Moderator Mr. Maher Nasser Director of the Outreach Division in the United Nations Department of Global Communications Opening Video Welcome Ms. Dima Al-Khatib Director of the United Nations Office for South-South Cooperation Keynote Messages Mr. António Guterres (video message) United Nations Secretary-General H.E. Mr. Khalilur Rahman President of the 81st Session of the UN General Assembly H.E. Mr. Amar Bendjama (TBC) Permanent Representative Algeria, President of the United Nations Economic and Social Council (ECOSOC) Remarks H.E. Mr. Omar Hilale Permanent Representative of Morocco, President of the 22st Session of the High-level Committee on South-South Cooperation H.E. Mrs. Laura Dupuy Lasserre Permanent Representative of Uruguay, Chair of the Group of 77 and China Mr. Alexander De Croo (video message) UNDP Administrator Launch of Global Alliance for South-South and Triangular Cooperation Moderated Interactive Discussion (per inscribed protocol)
Leveraging South-South Cooperation for Inclusive and Sustainable Development. Event organized by the Mission of the Republic of Indonesia. Watch the creative Economy beyond Borders!
Commemoration of the UN Day for South-South Cooperation around the world:
Creative Economy beyond Borders: Leveraging South–South Cooperation for Inclusive and Sustainable Development
Organized by: Indonesia, Cambodia, Mozambique, UNDESA, UNOSSC
Third Annual Meeting of Emerging Development Partners Network / Commemoration of the United Nations Day for South-South Cooperation / Technical Seminar on Monitoring the Effectiveness of Assistance to Least Developed Countries (LDCs) and Measurement of South-South Cooperation
Organized by: Government of Kazakhstan and Kazakhstan Agency of International Development (KazAID) UN Plaza, Almaty, Republic of Kazakhstan 10-11 Sept. 2026
International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) International Conference on “Innovations to Transform Dryland Agriculture through South–South Cooperation”
Organized by: ICRISAT
10-12 Sept. 2026
New Delhi, India
International Day of Science, Technology, and Innovation for the South
Organized by: Group of 77 and China UNHQ, New York 16 Sept. 2025 More information.
Rome-based Agencies UN Day Event
Webinar focusing on: Scaling Impact, Sowing Equity – Rural Women Driving South-South and Triangular Cooperation for Sustainable Agrifood Systems Organized by: FAO, IFAD and WFP Rome, Italy 29 Sept. 2026
On 31 August 2026, on the International Day for People of African Descent, the UN Movie Society of the United Nations Staff Recreation Council is honoured to present a special conversation with two-time Academy Award®-winning director Ben Proudfoot, director of THE EYES OF GHANA.
On this occasion, opening remarks will be delivered by H.E. Mr. Samuel Yao Kumah, Ambassador Extraordinary and Plenipotentiary, Permanent Representative of Ghana to the United Nations. Executive produced by former President Barack Obama and Michelle Obama, THE EYES OF GHANA is a documentary feature by two-time Academy Award-winning director Ben Proudfoot, following 93-year-old cinematographer Chris Hesse — personal cameraman to Ghana's founding President, Kwame Nkrumah — as he races against blindness and time to rescue and repatriate more than 1,000 reels of long-lost footage documenting the birth of African independence. The film's story of reclaiming a suppressed visual history speaks directly to the spirit of the International Day for People of African Descent, honouring the memory, culture, and resilience of people of African descent worldwide. The International Day for People of African Descent reminds us that recognition, justice, and development — the three pillars of the UN's Second International Decade for People of African Descent (2025–2034) — remain vital, unfinished work. THE EYES OF GHANA embodies that work: Chris Hesse's decades-long fight to save the footage of Ghana's independence from erasure, and Anita Afonu's mission to ensure that this history is never lost again. Movies hold the unique power to promote universal ideals, principles, and values so deeply enshrined by the United Nations, including peace, development, respect for human rights, cultural appreciation, the dignity of the human person, and equal rights for all. Founded at the United Nations Headquarters by Brenda Vongova, the UN Movie Society is committed to championing the goals and values of the United Nations through the universal language of motion pictures.
THE BRINK OF WAR is based on the incredible true story of the 1986 Reykjavík Summit in Iceland, where President Ronald Reagan and Soviet leader Mikhail Gorbachev met inside Höfði House for a high-stakes, closed-door negotiation at the height of the Cold War. Stripping away political theater, the film captures two opposing leaders locked in intense dialogue as they confront the existential threat of nearly 70,000 nuclear weapons and dare to imagine the total elimination of their nuclear arsenals. Though the summit ultimately collapsed over disagreements regarding the Strategic Defense Initiative (SDI), the mutual trust forged in that room paved the way for the groundbreaking 1987 INF Treaty a year later. By highlighting how direct, honest communication averted global catastrophe, the film serves as a powerful testament to the necessity of diplomacy on the UN International Day Against Nuclear Tests. The UN International Day Against Nuclear Tests reminds us that dialogue, mutual understanding, and the courageous pursuit of peace remain our strongest safeguards against atomic escalation and nuclear annihilation. Established by the UN General Assembly to raise global awareness about the catastrophic dangers of nuclear testing, this observance underscores that even the deepest geopolitical divides can be bridged when nations choose dialogue and negotiation over confrontation. THE BRINK OF WAR dramatically reinforces this vital message, showing that true leadership requires looking past suspicion to secure a safer, nuclear-weapon-free world for future generations. Movies hold the unique power to promote universal ideals, principles, and values so deeply enshrined by the United Nations, including peace, development, respect for human rights, cultural appreciation, the dignity of the human person, and equal rights for all. Founded at the United Nations Headquarters by Brenda Vongova, the UN Movie Society is committed to championing the goals and values of the United Nations through the universal language of motion pictures.
UN Movie Society of the United Nations Staff Recreation Council. Brenda Vongova, Artistic Director Interview with Michael Russell Gunn, Director of THE BRINK OF WAR
Written Message by the UN Secretary-General for the International Day Against Nuclear Tests
**************************** SPECIAL THANKS
UN Department of Global Communications UN Executive Office of the Secretary-General
Speech writing Unit
Angel Sarah Amro Junket Productions, Inc.
Opening and Closing Music
UN Chamber Music Society of the United Nations Staff Recreation Council Brenda Vongova, Artistic Director JOHANNES BRAHMS (1833 - 1897) Six Pieces for Piano, Op.118: 2. Intermezzo in A Major, Andante teneramente (arr. for Viola and Piano) Jeremy Kienbaum (Viola), Brenda Vongova (Piano).
10’ Opening
session:
- Opening remarks -Tentative speakers Rafael Peralta (Director
of NY Office) Japan
- Indonesia.
10’ Technical
Showcase:
Earth
Observation for
Lake
Monitoring
- Demonstration of Global
Wetland Watch and how
satellite-bas ed monitoring
supports lake extent,
wetland monitoring,
national reporting, and
evidence-based
management. Tentative speakers - UNEP – GWW (Stuart
Crane, remotely)
30’ MultiStakeholder
Panel
Discussion:
From Science
to Policy.
Suggested guiding questions :
• How can lake conservation be
better integrated into national
climate and biodiversity
strategies?
• What lessons can countries
s hare through South-South and
triangular cooperation?
• What technical and financial
support is needed to accelerate
action?
• How can momentum be
sustained toward the 21st
World Lake Conference?
Recognizing the critical importance and compounding crises faced by lakes, a special event to commemorate World Lake Day is being organized to elevate the global political and technical profile of sustainable lake management. Lakes and reservoirs contain more than 90% of the world's liquid surface freshwater. They are the lifeblood of ecosystems, driving local economies, securing food and drinking water for billions, and regulating local climates. Despite their critical importance, lakes globally face unprecedented threats from pollution, agricultural runoff, climate-induced evaporation, and rapid biodiversity loss.
Lake Chelan is the cleanest lake in America, due to its low mineral levels and low turbidity.
The Great Salt Lake is the dirtiest lake in the US right now, with by far the heaviest mineral load of any ranked lake (134,500 mg/L Total Dissolved Solids), as well as the lowest dissolved oxygen levels (3.65 mg/L) and the highest ammonia levels of any lake in the top ten dirtiest (0.92 mg/L).
Over 60 major lakes in America were assessed across eight different categories.
The Cleanest and Dirtiest Lakes at a Glance
A new report has revealed the cleanest and dirtiest lakes in America, with Lake Chelan ranking as the cleanest, while the Great Salt Lake in Utah ranks as the dirtiest due to its saline levels. The study, conducted by vacation rental platform Lake.com, analyzed all the available chemical data from the National Water Quality Monitoring Council (NWQMC) for 100 of America’s largest lakes, sampled from January 1st, 2021, until July 30th, 2026. The study evaluated eight of the most commonly measured characteristics that can indicate a lake’s cleanliness level:
Dissolved oxygen
Ammonia
Lead
Phosphorus
Sulfate
Total dissolved solids
Turbidity
pH levels
A total of 67 lakes reported at least three of these pollution factors and therefore qualified for the study. The findings were put into an index to produce a pollution score out of 10 to determine the safest and most dangerous lakes based on hygiene, pollution and more.
At the other end of the scale, Lake Chelan in Washington state is the cleanest lake in America. Lake Chelan has turbidity of just 2.00 NTU, meaning it’s extremely clear, and one of the lowest TDS levels at 30.25 mg/L. Lake Chelan also experiences low sulfate levels of 3.65 mg/L.
The Great Salt Lake in Utah is America’s dirtiest lake. Its water carries an extremely high mineral load, with total dissolved solids (TDS) of 134,500 mg/L, which is much more than any other lake in the study. TDS refers to the total minerals within water, including sulfates, chlorides, calcium, magnesium, potassium, bicarbonates and sodium, and indicates the general quality of water. While not necessarily a direct indicator of pollution itself, the levels highlight how dangerous it could be to ingest any water from the Great Salt Lake due to its extreme chemistry.
The Great Salt Lake is also the most poorly oxygenated lake in the ranking, with dissolved oxygen of just 3.65 mg/L. If this level were to drop below 2, the lake would become hypoxic, meaning fish would suffocate. It also reports the highest ammonia of any lake in the top ten dirtiest ranking at 0.92 mg/L, along with elevated lead at 2.09 µg/L. The Great Salt Lake is not a freshwater lake and is a terminal lake; therefore, there is no outlet for any mineral or chemical buildup.
Lake McConaughy in Nebraska and Lake Winnebago in Wisconsin rank second and third dirtiest, respectively. Lake McConaughy has turbidity levels of 5.50 NTU, while Lake Winnebago, Wisconsin’s largest inland lake, is ranked so low due to its high levels of phosphorus, which are 0.09 mg/L, along with a pH deviation of 1.58.
The fourth dirtiest lake in America is Lake Vermilion in Minnesota. Lake Vermilion is the second least oxygenated lake, behind the Great Salt Lake, with dissolved oxygen of just 3.90 mg/L.
Devils Lake in North Dakota is the fifth dirtiest lake in the country and is likely to be the smelliest of all, as it has the highest levels of sulfate (639 mg/L) due to no natural outlet to dilute sulfates over time. The smell of sulfate is often described as similar to ‘rotten egg’.
Despite ranking as the eighteenth dirtiest lake overall, Lake Moultrie in South Carolina is the most lead-contaminated lake included in the study, with samples detecting lead at 17.2 µg/L. There is no safe level of lead.
Lake Mattamuskeet in North Carolina shows the highest ammonia of any freshwater lake in the top ten, estimated at 0.67 mg/L. Ammonia should not be present at all in clean water, and when levels reach 0.53 mg/L, the water begins to become harmful to fish.
“America’s largest lakes remain, on the whole, clean and pleasant to swim in. Even the lakes at the top of our dirtiest table sit within the range you would expect for large natural bodies of water, which shows that there is good maintenance and care for them.
“However, with that in mind, some monitoring of lakes throughout the country is uneven from one lake to the next, so anyone looking to visit a lake, particularly swimmers, needs to check any signage near their local swimming spot and follow the advice given to them. No lake in the ranking is inherently dangerous, but you could be at risk of a stomach bug.” David Ciccarelli, CEO of Lake.com
