Water contaminated with toxic metals kills millions of people worldwide every year, a study suggests – and the majority of Americans drink it.
World Bank researchers claim that lead in drinking water is responsible for more heart disease than smoking or poor diet.
Using blood tests on thousands of adults in 183 countries, they simulated the number of deaths from heart disease caused by lead – with their model saying 5.5 million were caused by the heavy metal.
By comparison, smoking has been linked to two million deaths from heart disease worldwide, while high cholesterol contributes to 2.6 million deaths.
Researchers from Washington DC said their study was a “wake-up call” to remove lead from the water supply, as 56 percent of Americans still drink water contaminated with the heavy metal.
The above map from the pressure group the Natural Resources Defense Council (NRDC) shows the populations served by drinking water with the highest levels of lead contamination. Florida had the highest concentration of lead pipes, a separate study found
The above shows the number of main service lines per state. A service pipe is a pipe that connects a home to the water supply. Every house has one
Heart disease is the leading cause of death worldwide, after an estimated 8.9 million deaths in 2019 alone.
According to the Centers for Disease Control and Prevention (CDC), it is also the leading cause of death in the US, with 695,000 deaths per year.
Lead is an extremely toxic heavy metal that can build up in the body over time, leading to a range of heart problems.
In babies and small children, it can also cause damage to the brain and central nervous system, leading to language and speech problems and developmental delays.
The heavy metal leaches into drinking water through pipes made of the heavy metal that are still used in many countries, including the US.
These are mostly service lines, or pipes that connect homes to water pipes, with the Biden administration unveiling a $45 billion fund to address the problem.
Homes in Florida are the most likely to have lead pipes, studies suggest, followed by those in Illinois and Ohio.
Lead causes heart disease by causing high blood pressure, which happens because the heavy metal builds up in the body and causes blood vessels to narrow, reducing the amount of space for blood to flow through.
The metal can also cause this by damaging the kidneys, which can lower blood pressure by filtering water and nutrients from the bloodstream.
Lead is also known to cause cardiac arrhythmias, or abnormal heartbeats, by disrupting the nerves.
High blood pressure leads to heart disease by forcing the heart to work harder and increasing the risk of damage to the arteries, which can cause fatty plaques to build up.
For the research, published in Lancet Planetary Healthresearchers looked at data from the Global Burden of Diseases (GBD) study published in 2019.
Previous research has only estimated deaths from lead exposure based on figures on the number of adults suffering from high blood pressure.
But in this study, the researchers used a model that took into account other effects that lead has on the heart, such as cardiac arrhythmias.
The results showed that 90 percent of deaths from lead exposure occurred in developing countries.
The above shows the leading causes of death worldwide in 2019, according to the World Health Organization
They also found that children in developing countries lost an average of six IQ points due to damage from lead exposure.
This was six times higher than the previous figure and is estimated to cost the world $6 trillion a year.
Environmental economist Bjorn Larsen, co-author of the study, said that when they first saw the number it was so “huge” that they “didn’t even dare whisper it.”
Campaigners described the study’s findings as a ‘wake-up call’ for the world to take action on lead exposure.
Richard Fuller, the president of Pure Earth, said the results suggested the effects of lead may be even worse than initially feared.
But experts – such as air pollution scientist Dr Roy Harrison of the University of Birmingham, UK – tried to pour cold water on the findings.
He said the results were “interesting” but remained “subject to many uncertainties.”
He pointed out that the relationship between lead in the blood and heart disease that the model used was based on a study conducted in the United States, but that applying it to the entire world was a “huge leap of faith.”
The Natural Resources Defense Council – a US-based pressure group – estimated that between 2018 and 2020, 56 percent of Americans drank from water systems with detectable lead levels.