Lead is a toxic heavy metal found in polluted environments, in materials used for children’s toys, and even in everyday items. This poses a severe health risk to children, yet it is difficult to see or detect, only becoming apparent in cases of acute poisoning, which is often too late for effective intervention.
Lead and Lead Poisoning in Children
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Children who have a habit of sucking or kissing toys with paint are at a 3-4 times higher risk of lead exposure than other children, due to the high lead content in the paint. |
Research indicates that the average lead dust in urban air is about 1 mg/m3, and people, whether they want to or not, inhale approximately 1.5-20 mg of lead daily. In rural areas, this concentration is lower, around 0.1-0.2 mg/m3, resulting in daily inhalation of 1.5-4.0 mg of lead. According to World Health Organization (WHO) regulations, the limit for lead dust in workplaces must be less than 0.01 mg/m3, while in residential areas it should be under 0.005 mg/m3.
However, lead dust in industrial production areas often exceeds permissible levels. Along traffic routes, the average levels may be low, but during traffic jams or peak hours, they can spike significantly. Lead dust is generated from the exhaust of cars and motorcycles that previously used leaded gasoline. Although leaded gasoline is no longer in use, lead dust levels have not significantly decreased.
When children inhale lead at low concentrations of 1 mg/m3 for just one day (and then cease exposure), they do not show immediate symptoms of poisoning; effects may only become apparent after several weeks. Continuous exposure at concentrations of 0.1 mg/m3 over many days can lead to chronic poisoning.
Children are particularly sensitive to lead due to their developing nervous systems and poor detoxification capabilities. However, when lead enters the body through food, it can be difficult to detect because children consume a significantly higher volume of food relative to their body weight compared to adults, making it harder to identify lead exposure. For instance, studies have shown that the average lead intake through food for children is 50-150 mg/day, whereas for adults it is 100-200 mg/day. Children’s risk of lead exposure through food is four times greater than that of adults. If a child ingests 100 mg of lead sulfate per kilogram of body weight over multiple days, they may experience chronic poisoning.
Children who frequently suck their fingers or wipe their hands on their mouths are at a 4-5 times higher risk of lead exposure compared to typical children. The surrounding environment is filled with materials and air that are often contaminated with lead. Even toys painted with vibrant colors can contain significant amounts of lead. Children with habits of sucking or kissing toys with paint face a 3-4 times higher risk of lead exposure due to the high lead content in the paint.
For example, primer paints can contain 30,000-60,000 mg/kg of the paint solution. Areas on materials, tools, furniture, and toys that are blistered or damaged pose a high risk for lead contamination, even if the exterior appears intact. Current standards for toy production in the United States require lead levels to be less than 2,500 mg/kg of paint, while residential paint must contain less than 5,000 mg/kg.
In rural areas, children often find lead from various sources, melting it down to make flat lead pellets for playing games. They may also melt lead on stoves and cast it into marbles for play; or help parents cast lead for fishing tackle and nets. Additionally, children may work in battery production or car repair shops, or live near foundries and artisanal workshops where lead is used. Such activities expose children to lead through their hands and mouths, especially during the casting process when lead fumes can quickly enter their bodies, potentially causing acute poisoning.
Therefore, parents should not allow children to come into contact with or play with batteries or damaged batteries. Many parents are unaware of the dangers posed by these items, leading to poisoning that can accumulate over time, resulting in chronic exposure, bioaccumulation, and potentially leading to cancer or anemia, as lead can persist in the body for long durations and severely impact developing brain cells.
Research also indicates that lead in surface soil can be as high as 0.5-5.0 mg/kg. Children playing on the ground are at risk of chronic lead exposure. Studies have shown that the risk of lead contamination in children through food is 4-5 times higher than in adults.
On another note, it has been observed that an average cigarette contains 4.0-12.0 mg of lead, and approximately 20% of this lead is absorbed by smokers through cigarette smoke. Thus, if an individual smokes 20 cigarettes a day, they could absorb between 1-5 mg of lead daily. Reliable studies indicate that children with parents who smoke are 4-6 times more likely to suffer from lead poisoning than children whose parents do not smoke due to secondhand smoke exposure.
Sudden Death from Lead Poisoning
Lead is a heavy metal (with a density greater than 5 kg/dm3) that is highly toxic to the brain, capable of causing sudden death in severe cases, particularly in children. Children exposed to lead often appear pale, as lead inhibits hemoglobin synthesis, leading to anemia. Lead can replace calcium in a child’s new cells, affecting metabolic processes, and decreasing ATP (Adenosine Triphosphate) synthesis, damaging cell function.
Determining the amount of lead absorbed into a child’s body from soil and dust is quite challenging. According to experiments by foreign researchers, if a child absorbs around 25-100 mg of dust daily, which contains approximately 200 to 2,000 mg/kg of lead, they could absorb 5-200 mg of lead per day.
However, not all lead that enters the body enters the bloodstream; only a small portion does, while the rest accumulates in the liver, kidneys, and fat, with some expelled through feces, urine, and sweat.
Symptoms of Lead Poisoning
Symptoms of lead poisoning in children can often be difficult to detect, especially when lead levels are below dangerous thresholds, yet they can still cause chronic health issues. In such cases, children may exhibit nervous fatigue, weakness, irritability, and widespread pain.
Children with lead poisoning commonly suffer from anemia. Additionally, lead affects the digestive system, leading to reduced appetite, nausea, abdominal pain (which can be severe), and a pale complexion. Many lead toxins can lead to liver and kidney failure.
Lead poisoning is an environmental illness that is hard to detect yet is most common among children and adolescents. Parents should be particularly vigilant in urban areas with high waste, dust, paint, soil, and especially children’s toys.
Prof. Dr. Le Huy Ba (Vietnam National University, Ho Chi Minh City)
