Lead poisoning is simply the presence of excessive amounts of lead in the blood. In people’s traditional concept, once a person is poisoned, he or she will have a violent reaction such as black face, vomiting, coma, convulsions and even death within a short period of time, but lead poisoning as scientifically defined does not mean such symptomatic poisoning, but describes that the blood lead level in a person’s body is already at a dangerous level that is harmful to health.
Lead is a neurotoxic heavy metal element that should not be present in the body and should not be measured in the blood. It has no physiological function in human body, only toxic effect, and its ideal blood concentration is zero. At present, 100ug/L of blood lead is set as the clinically acceptable level. Above this level and accompanied by corresponding poisoning symptoms is lead poisoning. Children are particularly sensitive to the toxicity of lead due to the characteristics of metabolism and development, and the damage of lead poisoning to children’s brain is permanent, some countries in Europe and America have regarded lead poisoning as the “first kill” of children’s intelligent development, and lead poisoning in children in China is far more than that in industrialized countries.
What are the causes of lead poisoning in life?
There are many causes of lead poisoning, including dietary habits, tableware, cosmetics, furniture, etc., which may cause excessive lead to accumulate in human body. The consumption of lead-containing foods, such as eggs, popcorn, leaded soldered canned foods, fruit peels, etc.; frequent contact with color-printed food packaging, paint items, lead-containing cosmetics, hair dyes, lead-contaminated clothing, automobile exhaust, lead-containing drugs; lighting candles containing lead, especially scented and slow-burning candles, etc. Among them, for adults who usually have little contact with lead, the use of substandard colored glazed tableware may be an important reason for the excessive lead content in the body.
According to the introduction, substandard porcelain lead, cadmium and other heavy metals are very easy to dissolve from the beautiful appearance of the glaze, causing chronic harm to human health. Ceramic eating utensils are generally decorated by glazing its surface, where the presence of lead, cadmium and other heavy metals, when encountering acidic food, poor quality products will have excessive lead, cadmium leaching into the food. If people consume the food contained in products with excessive lead and cadmium content for a long time, it will cause lead deposition in the blood, resulting in damage to the central nervous system of the brain and the kidneys and other organs. Surface smooth as glass in the glaze, underglaze ceramic lead, cadmium leaching amount is very little or almost no, can be safe to buy; while the surface has a sense of bumpy glaze products should try to use the surface decorative pattern less products, for the uneasy products, available vinegar soak a few hours, if found that the color has obvious changes should be discarded.
What are the causes of occupational lead poisoning?
Industrial lead exposure includes: mining, sintering and refining of lead ore; smelting of lead-containing metals and alloys; manufacturing of storage batteries; casting words and pouring boards in the printing industry; cable wrapping lead; heat treatment of lead baths in the mechanical industry; welding of water pipes, food cans and electrical instrumentation components; manufacturing of bearings for trains and automobiles (hanging tiles); manufacturing of X-rays and atomic radiation protection materials; spraying lead for radio components; welding and cutting when repairing and dismantling old ships and bridges. . The above operations lead escapes in the form of vapor and soot. Lead compounds, such as lead oxide (also known as yellow dane, mithril), lead trioxide (also known as red dane), lead dioxide, lead trioxide, lead sulfide, lead sulfate, lead chromate (also known as chromium yellow), lead nitrate, lead silicate, lead acetate, basic lead carbonate, dibasic lead phosphate, trisodium lead sulfate, etc. are used in paints, pigments, rubber, glass, ceramics, glaze, drugs, plastics, explosives, etc. Compounds are dispersed in the form of dust.
At present, the most hazardous industries in China are battery manufacturing, lead smelting and dismantling of old ships, melting and cutting, etc. How does lead enter human body?
Lead and its compounds enter the body mainly through the respiratory tract, followed by the digestive tract, and cannot be absorbed through the skin.
Respiratory tract: It usually enters in the form of vapor, soot and dust, and the amount of lead inhaled varies with the size of dust particles, such as the absorption rate of 54% for dust particles of 0.27цm. Generally speaking, 70% to 75% of the inhaled lead is still excreted with the exhaled breath, and only 30% to 50% is absorbed into the human body.
Digestive tract: mainly from lead workplace eating and drinking water. The daily intake of lead in daily life food and beverage is about 300mg.
Lead is absorbed into the blood circulation in ionic state, mainly in the form of lead salts and combined with plasma proteins initially distributed in all tissues of the body, after a few weeks, about 95% of lead is deposited in the skeletal system and hair as insoluble lead phosphate, only about 5% of lead remains in the liver, kidney, brain, heart, spleen, basal nucleus, cortical gray matter and other organs and blood, and can enter the nucleus of cells and form?quot;inclusion bodies. And about 95% of the lead within the blood is distributed in the red blood cells, mainly in the red blood cell membrane, and only 5% in the plasma. Lead phosphate deposited in bone tissue is in a stable state, maintaining a dynamic balance with lead in blood and soft tissues. The absorbed lead is mainly excreted through kidney, but also through feces, milk, bile, menstruation, sweat gland, saliva hair, nails and other ways.
What is acute or subacute lead poisoning? What are its clinical characteristics?
Acute or subacute poisoning lead poisoning is mainly caused by lifestyle, mostly due to misuse or overuse of lead-containing prescriptions (containing lead acetate, lead carbonate, lead chromate, tetraethyl lead) to treat asthma, epilepsy, roundworm expulsion, abortion, etc. These lead-containing compounds such as lead, lead pellets, lead cream, mithridates, black pellets, camphor pellets, etc.; also use tin pots to make wine, tin pots to hold wine; there are also misuse of lead powder as yam powder and misuse. Foreign children are often poisoned by eating toys containing lead paint, walls, furniture and other peeled plaster. This kind of poisoning by oral intake often has an incubation period, short 4-6 hours, generally 2-3 days, the longest 1-2 weeks, which is closely related to the intake dose and individual differences, and is called acute or subacute poisoning lead poisoning. In addition, the use of cosmetics containing lead can also cause poisoning. Occupational subacute poisoning can also occur.
Its clinical characteristics are severe abdominal colic, anemia, toxic liver disease, toxic nephropathy, and multiple peripheral neuropathy. The manifestations include dizziness, general weakness, muscle and joint pain, inability to eat, constipation or diarrhea, liver enlargement, pressure pain in the liver area, xanthogranuloma, and elevated blood pressure. Laboratory tests: in addition to the obvious elevation of lead poisoning indicators, elevated bilirubin and elevated ALT; red blood cells, white blood cells, and positive uroporphyrin are seen in the urine; hematocrit and red blood cells are decreased. In the neurological examination, it can be found that the extremities end up with glove-sock type hypesthesia, muscle atrophy and muscle weakness. In severe cases, lead paralysis occurs, i.e., drooping wrists and feet.
What are the diagnostic criteria for lead poisoning?
At present, China has developed and implemented the diagnostic criteria for occupational chronic lead poisoning (BZ37-2002), which can be referred to for non-occupational adult chronic lead poisoning.
Occupational chronic lead poisoning is a systemic disease with neurological, digestive and hematopoietic system disorders due to exposure to lead fumes or lead dust. It needs to be diagnosed based on the exact occupational history and clinical manifestations mainly of neurological, digestive and hematopoietic systems and relevant laboratory tests, with reference to the investigation of operating environment, and comprehensive analysis to exclude similar diseases caused by other causes. It is divided into.
1.Observation object
Those who have a history of close lead exposure, no clinical manifestations of lead poisoning, with one of the following manifestations.
a urinary lead ≥ 0.34μmol/L (0.07mg/L, 70μg/L) or 0.48μmol/24h (0.1mg/24h, 100μg/24h).
b blood lead ≥ 1.9μmol/L (0.4mg/L, 400μg/L,).
c urinary lead ≥1.45μmol/L (0.3mg/L, 300μg/L) and <3.86μmol/L (0.8mg/L) after diagnostic lead repellent test.
2.Mild poisoning
1, blood lead ≥ 2.9μmol/L (0.6mg/L, 600μg/L) or urine lead ≥ 0.58μmol/L (0.12mg/L, 120μg/L); and with one of the following manifestations, can be diagnosed as mild poisoning.
a urinary δ-amino-r-ketovaleric acid ≥ 61.0 μmol/L (8 mg/L, 8000 μg/L)
b those with hematocrit free protoporphyrin (EP) ≥ 3.56 μmol/L (2 mg/L, 2000 μg/L).
c erythrocyte zinc protoporphyrin (ZPP) ≥ 2.91 μmol/L (13.0 μg/gHb).
d Symptoms of hidden abdominal pain, bloating and constipation.
2 diagnostic lead repellent test, urinary lead ≥ 3.86μmol/L (0.8mg/L, 800μg/L) or 4.82μmol/24h (1mg/24h, 1000μg/24h), can be diagnosed as mild lead poisoning.
3.Moderate poisoning
On the basis of mild poisoning, those who have one of the following manifestations.
a abdominal colic.
b anemia.
c Mild toxic peripheral neuropathy.
4.Severe poisoning
With one of the following manifestations.
a lead paralysis.
b toxic encephalopathy.
What are the diseases that need to be distinguished in lead poisoning?
Those with lead colic should be differentiated from appendicitis, biliary ascariasis, cholelithiasis, gastric perforation, hemoptysis, etc. Also, they need to be differentiated from other causes of anemia, hemolysis and neurological diseases. It needs to be done by a referral physician.
Must lead poisoning in children be detoxified with drugs?
The problem of lead poisoning in children is touching the hearts of more and more parents. Is it necessary to use medication for lead detoxification in children with lead poisoning? Not all cases of lead poisoning require medication for lead detoxification, but changing the living environment and correcting bad habits can prevent lead poisoning well. It is recommended not to blindly use drugs for lead detoxification, because lead detoxification drugs have large toxic side effects and will also excrete trace elements such as calcium, iron and zinc during the treatment process, and even serious low calcium will occur, leading to convulsions and even death, so children with lead poisoning are generally treated with non-pharmaceuticals, and in general, drug treatment is only carried out in the case of occupational poisoning. Eating seaweed, nori, black dates and drinking tea may have lead detoxification effect.
In addition, the lead pollution situation in China is complicated, besides indoor environment pollution, the air pollution caused by industrial waste gas and leaded gasoline is the main reason for the increase of blood lead in children. If the lead in the environment is not completely eliminated, even if the lead is eliminated from the body by the treatment of lead elimination, a large amount of lead will enter the body in a short period of time when they return to the lead-polluted environment. In this regard, experts suggest that parents should teach their children more about health, cultivate the good habit of washing hands and cutting nails regularly, and not to put foreign objects into the mouth. Wash toys for children often, and try not to take children to play in roads and factories with serious lead pollution. At the same time, give children less food containing lead, such as puffed eggs, canned food, etc. Lead elimination medicine will also excrete calcium, iron and zinc
What are the international diagnostic standards for lead poisoning in children?
At present, the diagnosis and grading of lead poisoning in children are mainly based on blood lead level.
Ⅰ, blood lead <100 micrograms/liter, relatively safe (already toxic to embryonic development, pregnant women are prone to miscarriage)
Ⅱ, blood lead 100～199 micrograms/liter, heme metabolism is affected and nerve conduction speed is decreased.
Ⅲ, blood lead 200～499 micrograms/liter, iron-zinc-calcium metabolism is affected, calcium deficiency, zinc deficiency, impaired hemoglobin synthesis, and may have symptoms such as low immunity, learning difficulties, inattention, decreased IQ level or physical growth retardation.
Ⅳ, blood lead from 500 to 699 micrograms/liter, may have symptoms of toxicity such as changeable personality, irritability, hyperactivity, aggressive behavior, motor disorders, vision and hearing loss, unexplained abdominal pain, anemia and cardiac arrhythmia.
V. Blood lead ≥ 700 µg/L can lead to kidney function damage, lead encephalopathy (headache, convulsion, coma, etc.) and even death.
For children with lead poisoning below II, health education, environmental intervention and special diet adjustment and balance are the main focus. For Ⅱ to Ⅲ, lead treatment must be done with nationally recognized lead repellent food under the guidance of doctors in order to make children with lead poisoning recover as soon as possible. Ⅳ to Ⅴ should have their blood lead checked within 48 hours, and if confirmed, they should be treated with lead repellent immediately, and the causes of lead poisoning should be investigated and intervened at the same time.
Note: Blood lead <60 micrograms/liter is relatively safe for children in developed countries around the world, and international blood lead diagnostic standard ≥100 micrograms/liter is considered as lead poisoning.
What should I do if my child has high blood lead?
Patients with blood lead level one to three, i.e. blood lead less than 45 Ug/dI, should take non-drug lead expulsion, methods include frequent hand washing, regular household cleaning, and eating less food containing lead. Secondly, we should use some health products with lead detoxification function, such as sea cucumber, seaweed, nori, black dates, green onion, wheat skin, oolong tea, prickly pear, kiwi, etc. Dietary fiber and other foods also have lead detoxification function. That is to say, the general lead poisoning in children is not as terrible as imagined, and there is no need to take a lot of lead detoxification medicine, which is harmful but not beneficial, but will cause harm to children’s body.
Parents are advised not to blindly believe in the “lead-repelling drugs” that are so much talked about in the society. Parents should regularly take their children to regular professional clinics to have their blood lead tested once a year, and once they find that their blood lead exceeds the standard, they should diagnose and treat it as early as possible.
How to prevent lead poisoning?
It is very important for individuals to strengthen the prevention and self-protection against lead poisoning. First of all, do not use lead-containing materials for eating utensils, and preferably do not use colorful glazed ceramic products for acidic food and drinks; try to go to streets or highways with high traffic flow and serious lead pollution, especially children should pay extra attention. Car drivers should not suck gasoline with their mouths, keep a certain distance from the car in front of them, and close the windows on crowded roads; traffic police, car mechanics and gasoline station workers should take a bath and change their clothes in time after work, and go to hospitals for regular checkups for timely detection and treatment.
Prevent lead poisoning in children: don’t let young children suck their fingers; don’t let them put foreign objects into their mouths and develop the habit of washing hands before eating; when using food, prevent the words, pictures or trademarks on plastic bags from coming into direct contact with food, especially greasy food and acidic food (such as doughnuts, hawthorn cake, etc.); avoid using pottery or vessels with colorful patterns painted inside the bowl to hold food, especially acidic drinks; don’t use paint at home to Do not use paint to beautify walls at home, and teach children not to put painted toys or utensils into their mouths to chew on them; do not bring children to play and stay for a long time near roads where cars are coming and going; do not give children food with high lead content, such as pine eggs. At the same time, parents should pay attention to the nutritional status of children, especially the supply of sufficient calcium, zinc, iron, vitamin C, vitamin B and protein in the diet, which is beneficial to reduce the lead load and harm in the body.
To prevent occupational lead poisoning: the key is to make the concentration of lead in the air of workshop reach the requirement of health standard, the following measures should be taken: replace lead with non-toxic or low-toxic, such as printing with zinc instead of lead plate, titanium white instead of lead white paint, etc.; reform the process, make the production process mechanized, automated and closed, reduce manual operation, such as mechanized casting instead of manual, use induction electric heating furnace to control lead furnace, install dust-absorbing exhaust hoods, and reduce lead poisoning. Temperature control, installation of dust-absorbing exhaust hood, recovery and purification of lead dust, etc. Workers working with lead should wear overalls and filtered anti-fume masks, eating in the workshop is strictly prohibited, they should wash their hands before meals and shower after work, and insist on wet cleaning. Regularly monitor the concentration of lead in the workshop air and overhaul equipment. Regular health examination. People suffering from nervous system, anemia, hypertension, liver and kidney diseases should not be engaged in lead work, and pregnant and breastfeeding women should be temporarily transferred from lead work.