Does it matter if cadmium exceeds the standard to water trees and flowers?

Excessive cadmium has an impact on watering trees and flowers, which will lead to yellowing and even death of plants.

Biological toxicity

Cadmium can irritate the respiratory tract, and long-term exposure can cause loss of sense of smell, and yellow spots or gradually yellow circles appear on the gums. Cadmium compounds are not easily absorbed by intestine, but can be absorbed by human body through breathing and accumulated in liver or kidney, causing harm, especially to kidney. It can also lead to osteoporosis and softening.

harm

There are acute and chronic poisoning. Inhalation of cadmium-containing gas can cause respiratory symptoms, and oral cadmium can cause liver and kidney symptoms.

Cadmium is not an essential element for human body. Cadmium in the human body is absorbed from the external environment after birth, and mainly enters the body through food, water and air for accumulation.

Cadmium absorption and metabolism: Cadmium dust can be inhaled through the respiratory tract. The absorption of cadmium by the lungs accounts for about 25 ~ 40% of the total intake. Smoking 20 cigarettes a day can inhale 2 ~ 4ug of cadmium. The absorption rate of cadmium through digestive tract is related to the type and intake of cadmium compounds and whether it is related to the intake of other metals. For example, when the intake of calcium and iron is low, the absorption of cadmium can be significantly increased, while when zinc is ingested, the absorption of cadmium can be inhibited. Cadmium absorbed into the blood is mainly combined with red blood cells.

Liver and kidney are two organs that store cadmium in the body, and the cadmium contained in them accounts for about 60% of the total cadmium in the body. It is estimated that the total amount of cadmium in normal people aged 40 ~ 60 is about 30mg, of which 10mg is in the kidney, 4mg is in the liver, and the rest is distributed in the lungs, pancreas, thyroid, testis, hair, etc. The content of cadmium in organs and tissues varies greatly with different regions and environmental pollution, and increases with age.

Cadmium entering the body is mainly excreted through kidney and urine, but a considerable part is excreted through liver and bile with feces. The excretion rate of cadmium is very slow, and the biological half-life of cadmium in human renal cortex is 10 ~ 30 years.

clinical picture

Cadmium and its compounds have certain toxicity. Inhalation of cadmium oxide smoke can cause acute poisoning. At the initial stage of poisoning, symptoms such as sore throat, cough, chest tightness, shortness of breath, dizziness, nausea, body aches, weakness, fever, etc. In severe cases, toxic pulmonary edema or chemical pneumonia may occur, with obvious dyspnea, chest pain and a lot of foamy blood sputum, and may die of acute respiratory failure. Adjust with cadmium-plated utensils

Bone pain and cadmium poisoning

Making or storing acidic food or drink may contain cadmium in the diet, which may also cause acute cadmium poisoning after eating it by mistake. The incubation period is short, usually after 10 ~ 20 minutes, symptoms such as nausea, vomiting, abdominal pain and diarrhea may occur. Severe cases are accompanied by dizziness, sweating, collapse, numbness of upper limbs, and even convulsions and shock. It usually takes 3 to 5 days to recover.

Long-term inhalation of cadmium will lead to chronic poisoning and kidney damage, mainly manifested in the large amount of low molecular weight proteins in urine. Although the filtration function of glomerulus is mostly normal, the recovery function of renal tubules decreases and the excretion of cadmium in urine increases.

Emphysema, anemia and bone changes of workers exposed to cadmium were also reported, but the exact relationship between these changes and cadmium exposure is still uncertain. It has also been reported abroad that workers exposed to cadmium oxide have a higher incidence of prostate cancer.

serious

Acute cadmium poisoning is not difficult to diagnose according to contact history and respiratory symptoms. In addition to occupational history and clinical symptoms, chronic cadmium poisoning should be diagnosed by combining chest radiograph, lung function, renal tubular function and urinary cadmium.

Acute cadmium poisoning is caused by inhalation. At first, there are symptoms of upper respiratory tract mucosal irritation, and the above symptoms are alleviated after detachment. After the incubation period of 4 ~ 10 hour, cough, chest tightness, dyspnea, chills, muscle joint pain in back and limbs, patchy shadows and thickening of lung texture can be seen in chest X-ray examination. Severe cases include pulmonary edema and heart failure. The clinical manifestations of poisoning caused by oral cadmium compounds are similar to acute gastroenteritis, such as nausea, vomiting, abdominal pain, diarrhea, general weakness, muscle pain and even collapse.

long-term

The early renal damage caused by chronic cadmium poisoning is characterized by the appearance of low molecular weight proteins (β2 microglobulin, vitamin A binding protein, lysozyme and ribonuclease, etc.). ) and diabetes, high amino acid urine, high phosphate urine. Chronic renal failure occurred in advanced patients. Pulmonary manifestations are chronic progressive obstructive emphysema, which eventually leads to pulmonary dysfunction. Patients with chronic poisoning are often accompanied by yellow spots on teeth and neck, loss of sense of smell, ulcer and atrophy of nasal mucosa, and others include loss of appetite, nausea, weight loss and hypertension. Long-term exposure to cadmium will increase the incidence of lung cancer.

Japan reported a chronic cadmium poisoning caused by drinking water contaminated with cadmium, which was called "painful disease". The clinical manifestations are low back pain, abdominal distension, dyspepsia, and many pathological fractures in severe cases. Laboratory examination showed that renal tubular reabsorption was impaired, urinary calcium and urinary phosphorus excretion increased, and blood calcium decreased. According to epidemiological investigation, pain is related to cadmium. Painful diseases are more common in women of childbearing age, so besides cadmium, there are also factors such as nutritional deficiency, calcium loss and endocrine.

Prevention and treatment

The treatment of acute poisoning caused by inhaling a large amount of cadmium oxide smoke is the same as that of general irritating gas poisoning. The key is to prevent pulmonary edema.

Leave the scene of the accident as soon as possible, keep quiet, stay in bed, take oxygen, keep the respiratory tract open, and use 10% silica gel to eliminate foam. Adrenal cortical hormone can reduce capillary permeability, so early quantitative use is appropriate. Limit the amount of liquid, give antibiotics to prevent secondary infection, take symptomatic treatment for acute cadmium poisoning by mistake, give plenty of rehydration and atropine injection to stop vomiting and eliminate abdominal pain.

Chronic cadmium poisoning causes kidney damage, so the intake of calcium and phosphorus should be increased in the diet, and sufficient zinc and protein should be supplemented. Metal complexing agent caNa2EDTA can increase cadmium excretion, but it can aggravate kidney damage. Not recommended for acute and chronic poisoning. It has been reported that oral nitrotriacetic acid (NTA) can promote the excretion of cadmium (mainly through feces), thus reducing the accumulation in the body without damaging renal function.

In order to prevent cadmium poisoning, places where cadmium and its compounds are smelted and used should have good ventilation and airtight devices. In addition to the necessary ventilation equipment, personal gas masks should be worn during welding and electroplating. You shouldn't eat or smoke in the workplace. The maximum allowable concentration of cadmium oxide in production sites in China is 0. 1mg/m3.

Cadmium pollutes the soil, which will cause public hazards and pain. Cadmium pollutes soil mainly through two forms. One is that cadmium in industrial waste gas spreads around with the wind and accumulates in the soil around the factory through natural sedimentation. The other is that industrial wastewater containing cadmium irrigates farmland, which makes the soil polluted by cadmium. Therefore, in order to prevent cadmium from polluting the environment, we must do a good job in environmental protection and strictly implement the environmental hygiene standards of cadmium.