Four well-known heavy metals and chemical pollutants – lead, asbestos, arsenic and cadmium- continue exact a heavy toll on the lives of those in low- and middle-income countries  – with lead named a factor in as much as 5 million premature deaths annually from cardiovascular disease, according to one recent estimate. Asbestos, arsenic, and cadmium round out the top four, claiming hundreds of thousands of lives every year.

While much recent media attention has been focused on the health impacts of newer industrial compounds such as dioxins, phthalates, and endocrine disruptors, these heavy metal “silent killers” need renewed attention in the environmental health arena, experts say.  

This was one key message from a day-long session on Health and Environment, the featured theme on the opening day of this year’s Geneva Health Forum, 27-29 May. The session highlighted the pressing threats of environmental pollution from plastics and lead to endocrine disruptors and ambient air pollution.

Migration, health and equity and malaria are other key themes

This year’s Forum, running on the sidelines of the World Health Assembly, brings together hundreds of scientists, policy experts and member state representatives on three key themes – including migration, health and equity; and malaria elimination – each the focus of a full-day session. There are also a host of side events on issues ranging from One Health to Climate resilience and elimination of neglected tropical diseases such as Chagas disease and Noma. 

While panellists highlighted the higher profile of air pollution in recent years and successes with air quality regulation in higher-income countries, air pollution remains a serious and even growing problem in low- and middle-income regions. 

Focus on pollutants with the highest impacts on death and disease

Meanwhile, age-old problems of heavy metal and mineral pollutants such as lead and asbestos also need much more attention, also in LMICs.   

“We need to deal with key priorities, country by country, of what’s causing the most damage,” said Richard Fuller, founder and former chair of the Global Alliance on Health and Pollution, who recently participated in an assessment ranking the burden of disease from key WHO “chemicals of concern.”

“There was one chemical issue that caused millions of deaths – and then four issues that caused hundreds of thousands of deaths,” he said, referring to lead, asbestos, highly hazardous pesticides, arsenic, and cadmium. “The one that caused the majority of deaths was our old friend lead, which is responsible for 1.5 -2 million deaths per year.”

Lead may account for as many as 5.5 million premature deaths from CVD 

A 2023 paper published in The Lancet, supported by the World Bank, estimated that lead exposure may cause up to 5.5 million premature deaths annually, with 95 per cent of those deaths attributed to cardiovascular diseases. The analysis draws on emerging evidence linking lead exposure to atherosclerosis, alongside its known effects on reduced IQ, the central nervous system, and other organs.

Mr. Fuller noted that the “lead problem,” once associated with pipes, paint, and gasoline, has evolved in affected low-income regions, but its impact remains just as devastating. “It turns out to be all sorts of activities going on in low- and middle-income countries, including [fabrication of] pots and pans and [contamination] of turmeric,” he explained.

“The ones that are less impactful … are things like dioxins, phthalates, brominated flame retardants, PFAS, endocrine disruptors, PCBs, and PAHs,” Mr. Fuller noted, emphasizing that these pollutants are “simply the noisier part of the agenda, but not necessarily the most impactful part of the agenda.”

“Should we be focusing on the ones that have the most impact, not just the most noise?” he added.

Ji John, an environmental epidemiologist at the Tsinghua University Vanke School of Public Health, told the forum he initially thought his 2013 dissertation on lead would be one of the last.

“Then Flint happened,” he said, referring to the water crisis in Flint, Michigan, which brought the issue of lead contamination back into the spotlight.

Air pollution remains a driver of poor health

With the World Health Organization attributing 13.7 million deaths to chemical and pollutant exposures, the Forum called attention to the need for global collaboration, research, and policy to tackle pollution-related health effects. 

“Clean air is possible, yet in some cities in the Asian and African continents, air pollution is getting worse,” said Nino Kuenzli, former Swiss Tropical and Public Health Institute professor. He acknowledged that air pollution regulation is part of a broader environmental health success story, citing the significant increase in air quality in Europe and North America in the past decades.

“The Swiss mountain town I grew up in had worse air quality than the Swiss urban centres today,” said Kuenzli, adding that this drastic improvement was built upon decades of scientific victories.

“We cannot just call for action and policy without a knowledge [of the science] and it is really fascinating to see how the science to understand the health effects of air pollution has evolved over the last 35 years. It’s incredible. Progress is enormous.” Advances in environmental epidemiology, and newfound ways for collaboration among basic scientists and toxicologists, have paved the way for these air quality improvements.

Addressing global air pollution inequalities and replicating much of the successes of higher-income countries means “leapfrogging” intermediate policies and technologies, argued John. For example, one of the largest sources of indoor air pollution comes from burning biomass fuels, yet countries often transition to gas stoves, which still produce air pollutants. Instead, countries could support a transition directly from biomass to electric, he said.

Plastic pollution: a new and growing threat

Plastics, now ubiquitous in the environment, are another kind of new, and growing pollution concern for soils, waterways, and air, when incinerated.

“By 2050, there will be more plastic than fish in the oceans,” remarked Fernando Espinosa, the Mexican Ambassador to Switzerland.

Plastic pollution got a brief nod on opening day following last month’s fourth Intergovernmental Negotiating Body in Ottowa, Canada to develop an international legally binding instrument on plastic pollution, including in the marine environment. While the negotiations did reach some conclusions, like developing a list of chemicals of concern, they did not agree to reduce the production of new plastics, most likely due to ongoing pressure from the fossil fuel lobby and their state backers, such as Saudi Arabia, Russia and the United States.

Climate adaptation and resilience in the healthcare system

The Forum also brought together experts to discuss the often negative environmental contributions of healthcare systems in lower- and middle-income countries. The sector has increasingly produced contaminated waste, greenhouse gas emissions, and other pollutants – causing upwards of five per cent of global greenhouse gas emissions. These emissions come from hospitals themselves, but also from the manufacturing of medical products.

Yet remarks from panellist Habib N’Konou, founder of an innovative biomedical waste company, during a later session demonstrated the disproportionate environmental impacts of the health sector in lower-and-middle-income countries. Senegal, he noted, produces upwards of 21,000 tonnes of medical waste per year, much of which is inadequately processed. “It’s an alarming situation. When I came back to Senegal, there was waste on the coasts, in neighbourhoods.”

Looking to the successes of other countries could pave the way for better biomedical waste management, N’Konou noted. Morocco and Tunisia both have government-mediated partnerships between waste facilities and hospitals, something N’Konou champions for Senegal and surrounding countries. Even when regulations exist, they are hard to enforce. 

Despite the environmental challenges facing LMICs, the climate crisis is an opportunity to rethink how healthcare systems operate, according to Sonia Roschnik, executive director of the Geneva Sustainability Centre. 

“This is where I really hope that some of what we do to respond to climate change is going to help us leverage more innovative ways of looking at healthcare that actually deliver better population health, but also help the planet.”

Image Credits: Prchi Palwe , EPA/L. Koula, Geneva Health Forum, HPW.