At present, there are more than 1400 battery manufacturers in China, and the output of 1999 reaches1500 million knots. About 366 million households in China need about 4.4 billion batteries every year. And most of them are consumed at home. Compared with many countries in the world, the recovery rate of waste batteries in China is extremely low. It is understood that 96% of the batteries produced in China are zinc-manganese batteries and alkaline-manganese batteries, and their main components are heavy metals such as manganese, mercury, zinc and chromium. No matter whether the waste battery is buried in the atmosphere or deep underground, its heavy metal components will overflow with leachate, causing pollution of groundwater and soil, which will seriously endanger human health over time.
1, ways of environmental pollution from waste batteries
The components of these batteries are sealed in the battery box during use, which will not affect the environment. However, after long-term mechanical wear and corrosion, heavy metals, acids and alkalis will leak out, enter the soil or water source, and enter the human food chain through various channels. The whole process is briefly described as follows: the battery enters the soil or water source-microorganism-animal-circulating dust-crops-food-human body-nerve-deposition disease.
Heavy metals ingested by other water plants and food-borne organisms from the environment can accumulate in thousands of higher organisms step by step through the biomagnification of the food chain, and then enter people's bodies through food and accumulate in some organs to cause chronic poisoning. Minamata disease in Japan is a typical case of mercury poisoning.
2. The harm of waste batteries to people
Hazardous wastes such as mercury, cadmium, zinc, lead and chromium are listed in 1998 national hazardous waste list;
Mercury: Mercury is a liquid metal. Specific gravity 13.6, melting point -39.3 degrees Celsius, boiling point 357 degrees Celsius. Mercury can evaporate at room temperature, and its vapor is colorless and tasteless, which is 7 times heavier than air. Mercury and its compounds are very toxic, especially the organic compounds of mercury are more toxic. Fish will be poisoned if they live in water with mercury content of 0.0 1-0.02 mg/L; If people eat 0. 1 g of mercury, they will be poisoned to death. Mercury and its compounds can invade human body through respiratory tract, skin or digestive tract. After entering human body, mercury accumulates in liver, kidney, brain, heart and bone marrow, causing neurotoxicity and deep tissue pathological changes, causing fatigue, dizziness, trembling, gingival bleeding, baldness, paralysis of hands and feet, neurasthenia and other symptoms, even insanity, and then crazy convulsions and death. Organic mercury can also enter the placenta, causing fetal congenital mercury poisoning, or malformation, or dementia. The toxicity of mercury is cumulative, and it usually takes years or longer to react. The food chain has a considerable ability to enrich mercury. For example, the enrichment multiples of freshwater fish and phytoplankton are 1000, freshwater invertebrates are10000, marine plants are1000, and marine animals are 200,000. Eating aquatic products contaminated with mercury will cause methyl mercury poisoning, dizziness, numbness of limbs, memory loss, insanity and even death, and will also affect the fetal malformation of pregnant women. Mercury thermometers commonly used at home are very dangerous!
Lead: The molecular weight of lead is 278, which is a heavy metal element. When heavy metal elements enter the human body, protein in the body will be denatured, that is, the normal function of protein will be destroyed, making the human body unable to play its normal function. Eating food containing lead will affect the synthesis of enzymes and normal heme, and affect the mental system. Lead accumulates in bones and kidneys, which has potential long-term effects.
The activity of lead in human body is much higher than that of calcium, iron and zinc, so when lead poisoning enters human body, it will replace zinc, iron and calcium plasma necessary for human body, thus causing symptoms of calcium deficiency, iron deficiency and zinc deficiency in human body, which is also the real reason why children are more prone to iron deficiency, zinc deficiency and calcium deficiency in today's polluted environment. In other words, to fundamentally solve the symptoms of iron deficiency, calcium deficiency and zinc deficiency in children, it can only be achieved after lead is discharged.
Studies have found that children's personality will change after exposure to toxic lead. They found that children became restless, not as obedient as before, and aggressive. It usually becomes violent after frustration. Mothers' findings have been scientifically confirmed-now, people know that lead is related to cognitive impairment, learning disabilities and various behaviors that may prevent them from completing secondary school.
If the child has learning difficulties, hyperactivity symptoms, inattention and sudden decline in grades, it is likely to be caused by lead poisoning. There are also some children who can't sit still all day, always want to kick things, and can't control themselves completely, which may also be a precursor to lead poisoning. Because lead is a heavy metal element with neurotoxicity, and children's nervous system develops rapidly, the resistance to external toxic substances is the most fragile. Research shows that children's absorption rate of lead is 50% higher than that of adults.
Every time children's blood lead level rises 100 μ g/L, their IQ will drop by 6 to 8 points. In addition, children with high blood lead are often shorter than normal children, which may also lead to anemia.
So how to prevent lead poisoning?
First of all, pay attention to diet and beware of children biting pencils. In addition to the usual saying that automobile exhaust is the main cause of lead poisoning in children, "lead in the mouth" can not be underestimated. Children generally prefer to eat puffed food such as popcorn, but the stoves and covers of popcorn machines made in the street are made of pig iron with high lead content. Because of the low melting point of lead, it is easy to volatilize and penetrate into popcorn under the condition of closed heating, leading to lead poisoning. In addition, some studies show that the more children drink canned drinks, the higher their blood lead levels, which may be related to the fact that many metal cans still use lead and tin as welding materials.
At the same time, children like to suck their fingers and bite things, so excessive lead content in stationery such as pencils, crayons and oil pastels can easily lead to lead poisoning.
Secondly, we must insist on washing our hands frequently. Because children's lead poisoning has no special discomfort and no clinical manifestations that parents and doctors can see, many people do not pay attention to it. This is also the reason why lead poisoning in children is called "hidden killer" abroad. In this regard, experts said that even children living in ordinary environment are prone to deposit a certain amount of lead on their hands after playing for a day, so they should pay attention to washing their hands frequently. In addition, children's toys and other items that may be put into children's mouths should also be cleaned frequently, because lead dust often adheres to them. Some wooden toys also contain lead, so they should not be used as children's toys.
Cadmium: Cadmium is a very toxic heavy metal, and most of its compounds are toxic substances. The "pain" in Japan that shocked the world was caused by cadmium pollution. Mine wastewater containing cadmium pollutes the soil, grain and pasture on both sides of the river, enters the human body through the food chain and slowly accumulates in the kidneys and bones. Will replace the calcium in the bone, so that the bone is severely softened and fractured; Cadmium can cause gastric dysfunction, interfere with the human body and the body's zinc enzyme system, reduce the proportion of zinc and cadmium, and lead to an increase in hypertension. The toxicity of cadmium is potential. Even if the concentration of cadmium in drinking water is as low as 0. 1 mg/L, it can accumulate in human tissues (especially women), and the incubation period can be as long as ten to thirty years, and it is not easy to be detected in the early stage. Data show that the biological half-life of cadmium in human body is 20 ~ 40 years. Cadmium is toxic to human tissues and organs in many ways, which is extremely difficult to treat. Therefore, countries have made very strict regulations on cadmium in industrial "three wastes" discharge. Japan also stipulates that rice with cadmium content exceeding 1 mg/kg is "cadmium rice" and is prohibited from eating. According to the Japanese Environment Agency, the highest normal content of cadmium concentration in rice is 0.3ppm. Because cadmium compounds have different degrees of toxicity, any method to remove cadmium from wastewater can only change its existence, and any method to remove cadmium from wastewater can only change its existing mode and transfer its existing position, but can not eliminate its toxicity. Therefore, the treatment of cadmium-containing wastewater should be combined with resource utilization as much as possible.
Manganese: Manganese is a heavy metal poison. Common manganese compounds are manganese dioxide, manganous tetroxide, manganese chloride, manganese sulfate, calcium chromate, manganese carbide, calcium acetate and potassium permanganate. Smoke and dust of manganese and its compounds enter human body through respiratory tract, which mainly causes chronic manganese poisoning. Acute manganese poisoning is very rare. Long-term exposure to manganese dust can cause diseases dominated by extrapyramidal nerve disorders. The paint used to decorate the house is rich in manganese, and children may get leukemia after inhalation. At present, leukemia and lymphadenopathy account for half of childhood tumors, and malignant tumors have become the top two or three deaths of children.
In a poorly ventilated working environment, after inhaling a large amount of newborn manganese oxide smoke, metal smoke fever occurs: dizziness, headache, fatigue, nausea, chest tightness, dry throat, shortness of breath, fever, etc. In severe cases, chills and chills may occur. Generally, after a few hours to 1 ~ 2 days, the fever is gone and the whole body is sweating. Inhalation of high concentration calcium compounds in a short time can cause chemical bronchitis and pneumonia. After taking potassium permanganate orally, the mouth, throat and digestive tract are rapidly corroded. Mild patients mainly have burning sensation in mouth, nausea, vomiting and epigastric pain. In severe cases, it will also cause swelling of the oropharynx and difficulty in swallowing. In severe cases, the oral mucosa was brown-black, swollen and erosive, accompanied by severe abdominal pain, vomiting, bloody stool and shock, and eventually died of circulatory failure. The lethal dose of potassium permanganate is about 5 ~ 199. Occupational chronic manganese poisoning is a disease with nervous system changes caused by long-term exposure to manganese dust. The early manifestations are neurasthenia syndrome and autonomic nervous dysfunction. When poisoning is obvious, extrapyramidal damage may occur, which may be accompanied by mental symptoms. Severe cases can be manifested as Parkinson's syndrome and toxic psychosis. At present, there is no specific laboratory diagnostic index for manganese poisoning. Urine manganese and hair manganese can only be used as exposure indicators.
Chromium: Chromium is a kind of metal with silvery white luster, which is non-toxic and chemically stable. Stainless steel contains more than 12% chromium. Common chromium compounds include hexavalent chromic anhydride, potassium dichromate, sodium dichromate, potassium chromate and sodium chromate. Trivalent chromium trioxide (chromium green, Cr2O3); Bivalent chromium oxide. Among chromium compounds, hexavalent chromium is the most toxic, followed by trivalent chromium. According to research, chromium is a trace element necessary for the life and health of mammals. Lack of chromium can lead to atherosclerosis. Adults need 500-700 micrograms of chromium every day, but the general diet can only provide 50- 100 micrograms. Brown sugar, whole grain brown rice, unrefined oil, millet, carrot and pea have higher chromium content. Chromium can stimulate plant growth, and trace chromium can increase plant yield; However, a slightly higher concentration will inhibit the nitrification of organic matter in soil. Chromic acid, dichromate and its salts can irritate and burn human sticky mold and skin, and lead to injury and contact dermatitis. These compounds enter the human body in the form of steam or dust, which will lead to perforation of nasal septum, gastrointestinal diseases, leukopenia and lung diseases like asthma. Skin contact with chromium compounds can lead to "chrome sores", which heal very slowly. When the concentration of chromic anhydride in the air reaches 0. 15 ~ 0.3 1mg/m3, the nasal septum can be perforated. Trivalent chromium is also a protein coagulant. Some people think that hexavalent chromium can induce lung cancer. In addition, hexavalent chromium, especially chromic acid, has a strong cultivation effect on metal pipes in sewage system, and sodium dichromate with a concentration of 2.3 1 mg/L can corrode pipes. Irrigation with trivalent chromium wastewater containing 3.4- 17.3mg/l can poison all plants. Chromium pollution is mainly caused by industry. Chromium compounds will be discharged from mining, smelting, manufacturing chromium salts, electroplating, metalworking, tanning, painting, pigment and printing and dyeing industries. For example, in the tanning industry, it is generally necessary to mail 50-60 tons of wastewater containing chromium 4 10mg/l to treat one ton of hides. If ten tons of hides are treated every day, 72-86 tons of chromium will be discharged every year. Chromium enters the human body and distributes in the liver and kidneys, leading to hepatitis and nephritis.
The components of these batteries are sealed in the battery box during the use of the battery, which will not affect the environment. However, after long-term mechanical wear and corrosion, heavy metals, acids, alkalis, etc. are leaked out and enter the soil or water source, and will enter the human food chain through various channels. Heavy metals ingested by organisms from the environment can be accumulated step by step in thousands of higher organisms through the biomagnification of the food chain, and then enter the human body through food and accumulate in some organs to cause chronic poisoning.
3. Waste batteries endanger other properties.
A button cell can pollute 600,000 liters of water, which is equivalent to the amount of water a person drinks in his life. A rotten battery in the ground can make a square meter of land useless. At present, the treatment of domestic waste in the world is mainly in four ways: sanitary landfill, reuse, composting and incineration. In these four processes, the pollution effects of waste batteries mixed with domestic garbage are as follows:
Landfill: Heavy metals in waste batteries pollute water and soil through infiltration.
Incineration: waste batteries corrode equipment at high temperature, and some metals volatilize in the fly ash of incinerator, causing air pollution.
Compost: The main raw material is domestic garbage. Garbage and old batteries become organic fertilizers after composting, which are applied to field soil by farmers, and heavy metals are absorbed by crops and enter our food chain.