Very low levels of lead contamination can still be harmful to health and should not be taken lightly | Science and Technology News |

Lead is a toxic heavy metal that can damage organs and tissues such as nerves, cardiovascular systems, kidneys and bones. In addition to affecting children’s intelligence, it also increases the risk of high blood pressure and cardiovascular disease in adults. Studies show that cardiovascular disease caused by low dose lead poisoning kills 5.5 million people every year! In a review paper published in the authoritative medical journal “New England Journal of Medicine” at the end of October, scholars reiterated that the health risks of low-dose lead poisoning still exist and that governments around the world cannot to take the world lightly.

Lead is a metal that has the advantages of ductility, high density, and corrosion resistance, and has been widely used since ancient times. Human use has increased dramatically in the 20th century.In addition to being widely used as a gasoline additive to reduce “engine knocking”, it is also used in the manufacture of water pipes, paints, batteries and welding materials, and even in the production of pesticides. Various applications show modern humans to drive concentrations much higher than natural levels. Although lead exposure levels have fallen by more than 95% since the 1970s, lead levels in people today are still 10 to 100 times higher than pre-industrial levels.

Two thousand years ago, the Greek pharmacist Dioscorides described the symptoms of lead poisoning, which included fatigue, headaches, irritability, severe abdominal cramps, and constipation. When the blood lead concentration exceeds 800 micrograms/liter, acute lead poisoning can cause epilepsy, brain damage and death. In addition, lead poisoning was linked to arteriosclerosis a century ago. In an autopsy study, more than half of the people with chronic lead poisoning had arteriosclerosis.

In 1988, scientists reported to the US Congress that “lead is ubiquitous and potentially toxic wherever it is found. A Canadian study showed that for every 10 micrograms/liter increase in maternal blood lead levels, the risk of preterm birth increased by 70%. increase more than 5 times in the school ten years later.

Monitoring bone lead levels helps predict risk better than blood lead levels

Long-term exposure of adults to low-concentration lead pollution may also cause chronic kidney failure, hypertension and autonomic nervous system disorders. Even very low concentrations, considered safe in the past, can be dangerous. Even blood lead concentrations as low as 35 micrograms/liter can cause harm. Therefore, there is currently no known safe blood lead concentration; The World Health Organization (WHO) also pointed out that there is no “safe” exposure value for so-called lead pollution also saying: ” Safe levels of blood lead in children have not yet been established.”

Although developed countries have phased out leaded gasoline, paint, and water pipes to reduce lead exposure, in developing countries, lead exposure has not decreased but increased. Dr. Ana Navas-Acien, lead author of this review paper and professor of environmental health sciences at Columbia University, said: “The global burden of disease caused by lead exposure is enormous. Developing China’s crowns The incidence of heart disease has continued to rise over the past 30 years, and over 600 million children worldwide are exposed to lead poisoning! “

The paper also suggests that testing bone lead levels appears to be more helpful in predicting risk than blood lead levels and is worth adopting. But the basic solution to protect people from lead poisoning is to eliminate lead from the environment. Dr. Navas-Achien emphasized that countries should continue to phase out lead acid batteries, replace leaded water pipes, ban the use of leaded jet fuel, remove leaded paint from old houses, and reducing further lead-contaminated soil. to completely eliminate lead exposure.

(Source of first image:Unsplash)

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