Heavy metal pollution in China is sporadic in the north and relatively dense in the south. In parts of Hunan, Jiangxi, Yunnan, Guangxi and other provinces, there are some contiguous distributions.
Heavy metal cadmium is invading rice through polluted soil; Scholars' sampling survey shows that about 10% of rice cadmium exceeds the standard in many markets in China. China was almost undefended before rice was polluted by all kinds of heavy metals.
"New Century" Weekly reporter Gong Jing
Li Wenxiang, 84, took out half a bag of rice from under a table with mottled paint. The color is pure white, slightly translucent and full of particles, and the naked eye can't see any difference between these rice.
However, after testing, the cadmium content of this rice seriously exceeded the standard. The locals call this rice "cadmium rice" for short.
Heavy metal cadmium ranks 48th in the periodic table of chemical elements. In nature, it exists in minerals in the form of compounds, which is extremely harmful after entering the human body.
Old Li Man Wen Xiang suspected that his strange disease was related to this rice. The old man is still in good health, but he has been unable to walk well for more than 20 years. As long as you don't walk more than 100 meters, your feet and calves will be sore.
The doctor couldn't make a definite diagnosis, so the old man simply named himself-limp foot disease. He told this reporter that in Sidi Village, Xingping Town, Yangshuo County, Guangxi, where he lives, more than a dozen other elderly people have similar symptoms.
Li Wenxiang has been eating rice produced in his village for 28 years since he retired to his village in 1982. Many scholars' research papers confirmed that the cultivated soil in this village had been polluted by heavy metal cadmium as early as 1960s. Correspondingly, the cadmium content of the produced rice is also seriously exceeding the standard.
Medical literature has proved that cadmium will cause diseases such as bone pain after many years, and even lead to terrible "pain disease" in severe cases. The so-called "pain syndrome", also known as osteopathy, was named in Japan in the 1960s. Because of mining in this country, cadmium seriously pollutes farmland, and farmers eat rice and other foods on polluted soil for a long time, which leads to cadmium poisoning. The patient's bone is as painful as a needle, and he often cries "pain, pain", hence the name. The symptoms of this disease are very similar to those of limp feet mentioned by Wen Xiang, an old Li Man. Many scholars also pointed out that many villagers in Sidi Village have initial symptoms of suspected "pain".
Similar cases are not limited to Side Village in Guangxi. In fact, in many places, there are serious urinary cadmium exceeding the standard and corresponding symptoms.
In particular, it is worth mentioning that about 10% of rice in China has the problem of cadmium exceeding the standard, whether it is the spot check of agricultural departments or the research of scholars in recent years. This is undoubtedly a heavy reality for the country with the largest rice consumption in the world.
In addition to cadmium, there are other heavy metals in rice that exceed the standard. Researchers from the Institute of Geochemistry, Chinese Academy of Sciences published a paper saying that the main source of methylmercury intake of inland residents in China is rice, not fish. As we all know, methylmercury is the chief culprit of Minamata disease, one of the famous public hazards.
A complete food contamination chain has been going on for many years. In the process of rapid industrialization in China, harmful heavy metals such as cadmium, arsenic and mercury in the form of compounds are released into nature. These harmful heavy metals have polluted a considerable part of land in China through water and air, and then polluted rice, and then entered the human body.
Tens of millions of rice farmers in polluted areas are the biggest victims. Rice is their absolute staple food for three meals a day. Some farmers know that there is pollution, but they are trapped in the difference between selling dirty rice and buying clean rice, and are forced to eat contaminated rice. More farmers don't know that the rice they eat is poisonous, and they don't even know what heavy metals are.
What's more, there are almost no planting norms for heavy metal polluted land in China, and a large number of polluted land are still producing rice normally.
Moreover, most of the polluted rice produced on the polluted land can be freely listed and circulated without hindrance. This leads to the exposure risk of urban and rural residents outside the origin of contaminated rice, and the degree of risk is still lacking.
Strange diseases in Sidi village
Many soil scholars anonymously mentioned Guilin Temple Village in their papers and lectures, claiming that many villagers had the initial symptoms of suspected "painful diseases", "chicken soft eggs and newborn calf cartilage"
Qin Guixiu, 7 1 year old, is another "soft-footed" old man in Sidi Village. In the last four or five years, her legs have been weak and have no strength. It hurts when she walks. Besides, her waist often hurts. She went to a big hospital in Guilin and was diagnosed as "bone calcification". The specific cause, the doctor said not clearly.
She said that more than a dozen people in this village have such symptoms, and maybe 50 people have them. However, a village cadre in this village does not agree with her statement, thinking that low back pain is very common in rural areas, and such statistics are meaningless. This cadre can't explain why so many people have the same symptoms.
In fact, many soil scholars in China mentioned Sicun anonymously in their papers and public lectures, saying that many villagers in the village had the initial symptoms of "painful illness"; There has been a phenomenon in the village that "chickens give birth to soft eggs and newborn calves suffer from rickets".
Our reporter asked some scholars about this matter, and scholars revised the above statement. They believe that it is more accurate to say that some villagers have the initial symptoms of suspected "pain". The embarrassment of scholars is that so far no official or medical unit has confirmed what the above symptoms are.
20 10 12, when our reporter visited the side village, many villagers privately confirmed that there were indeed many people in the village suffering from systemic pain. A villager who married from a foreign village in the early 1980s said that at that time, girls from other villages were unwilling to marry in their own village, saying that the children born would be "losers". After getting married, she found this statement a bit exaggerated, but people's worries have not been eliminated so far.
The villagers confirmed that the state-owned grain depot had exempted the village's public grain before the grain was fully liberalized. The official who collected the grain said, "The rice in your village is poisonous." The biggest difference between the villagers in this village and those in other villages is that they can only eat "poisonous" rice that the country does not want.
In the severe winter, the cultivated land outside the village is full of rice stubble left after rice harvest, and some vegetables next to it grow green and lovely. However, the nearly 1,000 mu of farmland named Datian is really "sick": the measured data in 1986 shows that the available cadmium content in the above land is as high as 7.79 mg/kg, which is 26 times the national allowable value.
Lin Bingying, a professor at Guilin Institute of Technology in Guangxi, studied in this village. The results show that in 1986, the cadmium content of early rice is three times the national allowable value of 0.2 mg/kg, and that of late rice is more than five times the specified value, reaching 1.005 mg/kg.
A person in charge of the Agricultural Environmental Protection Station of Yangshuo County Agriculture Bureau told this reporter that so far, the heavy metal situation in this land has not improved much. A senior agricultural expert said that cadmium pollution is quite irreversible. Once the soil is polluted, even after many years, the cadmium content in the crops will only change slightly.
The water source of paddy field is the side river flowing through the village, and the pollution source is the lead-zinc mine 15km away from the upstream of the village. This small-scale mine has been mined in this county as a state-owned mine since 1950s. At that time, there were almost no environmental protection facilities, and wastewater containing cadmium flowed into villagers' farmland as irrigation water.
According to statistics, * * * has more than 5,000 mu of land polluted by this mine, and Dadongtian is the most serious one, 1 1,000 mu. Later research showed that the cadmium content in early mine wastewater exceeded the agricultural irrigation quality standard 194 times.
The benefit of this lead-zinc mine is not good It has been off and on for decades, and now it has been transferred to private hands. At the same time, no villagers clearly know whether these "poisons" from rice have entered their bodies and what happened after entering. Most people can't prove that their pain is a disease, let alone its correlation with rice.
10% rice cadmium exceeded the standard.
Pan Genxing's team of Nanjing Agricultural University randomly purchased samples in many markets above the county level in China. The results showed that about 65,438+00% of the rice sold in the market was polluted by cadmium, and it was not only the rice in Sidi Village.
In 2002, the Center for Quality Supervision, Inspection and Testing of Rice and Rice Products of the Ministry of Agriculture conducted a safety sampling inspection of rice in the national market. The results showed that lead was the most serious heavy metal in rice, with an over-standard rate of 28.4%, followed by cadmium, with an over-standard rate of 10.3%.
Five years later, in 2007, Pan Genxing, a professor at the Institute of Agricultural Resources and Eco-environment of Nanjing Agricultural University, and his research team randomly purchased 9 1 sample of rice in markets above the county level in six regions of China (East China, Northeast China, Central China, Southwest China, South China and North China). The results also showed that about 10% of the rice in the market exceeded the standard.
Their research was later published in the journal Safety and Environment. But unfortunately, such an important research has not attracted much attention.
A number of scholars told this reporter that, because most of the polluted paddy fields grow rice without restriction, 10% of the rice with excessive cadmium basically reflects the current reality in China.
The annual output of rice in China is nearly 200 million tons, 65.438+00% or 20 million tons. Such a huge number is enough to illustrate the seriousness of the problem. The research of Pan Genxing's team also shows that the heavy metal pollution of rice in China is mainly caused by southern indica rice, especially in Hunan and Jiangxi provinces. In April 2008, Pan led his research team to randomly select 63 samples from farmers' markets in Jiangxi, Hunan and Guangdong provinces. The experimental results confirmed that more than 60% of the rice cadmium content exceeded the national limit. One of the important reasons for such a high value is that super hybrid rice planted in acidic soil in southern China absorbs cadmium more easily than conventional rice, but in addition, the cadmium pollution problem of rice in southern provinces is still extremely serious.
Pan Genxing told this reporter that the grim situation of rice pollution in China cannot be fundamentally changed in the short term.
Researcher Chen, director of the Environmental Restoration Research Center of the Institute of Geographical Sciences and Resources, Chinese Academy of Sciences, has devoted himself to the research of soil pollution and restoration for many years. He told this reporter that heavy metal pollution in China is sporadic in the north and relatively dense in the south. In parts of Hunan, Jiangxi, Yunnan, Guangxi and other provinces, there are some contiguous distributions.
Chen disagrees with the widely circulated statement that one fifth of cultivated land in China is polluted by heavy metals. According to his large-scale investigation in some provinces and cities for many years, he estimated that heavy metal pollution is likely to account for about 10%. Among them, cadmium pollution and arsenic pollution account for the largest proportion, accounting for about 40% of polluted cultivated land respectively.
If Chen's estimation is true, the land polluted by cadmium and arsenic is nearly 65.438+0.8 billion mu, and the land polluted by cadmium alone may reach about 80 million mu.
What makes people feel heavy is that most of these polluted areas are still planting rice, and farmers mainly eat their own rice. Not only that, rice contaminated by heavy metals also flowed to the market. In the face of rice contaminated by heavy metals, the health of China people is almost defenseless.
Trace cadmium pollution
In Xinma Village, Zhuzhou, Hunan Province and Dabaoshan, Guangdong Province, rice has been seriously polluted.
In Xinma Village, Zhuzhou City, Hunan Province, which is more than 2000 kilometers away from Side Village in Guangxi, a cadmium pollution incident occurred in June 5438+ 10, 2006. Two people died, and 150 villagers were diagnosed as chronic mild cadmium poisoning after physical examination. In September of that year 1 1, the Hunan provincial government announced the investigation results, and found that the drinking water and groundwater in the village were not polluted by cadmium, but the cultivated soil was polluted by cadmium, and the heavy metals in rice seriously exceeded the standard.
20 1 1 1, our reporter once again came to this village in Ma Jiahe Town, Tianyuan District, Zhuzhou City. The local government announced that 1000 mu of land in this village and two neighboring villages had been abandoned. Up to now, the villagers believe that the cadmium-containing wastewater discharged from the motorcycle parts factory in the village is the most direct cause of cadmium poisoning, but the cadmium pollution of rice advocated by the government is also considered by the villagers as an important cause.
The local government has not officially announced the cadmium content in rice in this village. Professor Pan Genxing from Agricultural Research Institute of Nanjing Agricultural University and his party asked villagers for two copies of original rice for laboratory testing in April 2008. The results showed that the cadmium content was 0.52 mg/kg and 0.53 mg/kg, respectively, which was 2.5 times of the national standard.
Cadmium pollution of cultivated land in Xinma Village of Zhuzhou mainly comes from Xiangjiang River, which is 1 km away. Xiangjiang River is the most polluted river in China, and Xiawan Industrial Zone, a few kilometers upstream of Xinma Village, is one of the main sources of heavy metal pollution in Xiangjiang River.
Around several industrial zones in Zhuzhou City, dozens of square kilometers of farmland are polluted by heavy metals. Villagers in Xinqiao Village, located at the edge of Xiawan Industrial Zone, confirmed to our reporter that thousands of acres of land in Xinqiao, Xiawan and Jianshe Village were polluted by heavy metal wastewater discharged from Xiawan Industrial Zone as early as the 1980s. The local government subsidizes 800 Jin of rice per mu of paddy field every year, which has been the case for more than 20 years.
In Zhuzhou and Xiangtan sections of Xiangjiang River, a large amount of land on both sides of the river is directly irrigated with Xiangjiang water. Theoretically, they are likely to be polluted, but there is a lack of research and data in this field. Wang Guoxiang, vice president of Xiangtan Environmental Protection Association, once invested in testing soil and rice pollution in Tangyan Village, Yisuhe Town, Xiangtan County. As a result, the cadmium content in soil and rice seriously exceeded the standard.
Before and after sampling in Xinma Village in 2008, Pan Genxing and his party also went to several other cadmium-polluted areas widely reported by the media for rice sampling. These places include Dabaoshan in Guangdong, Bailutang in Chenzhou, Hunan, and Fuyu Piaotang in Jiangxi. Experiments show that the rice pollution in these places is serious, and the cadmium content is as low as 0.4 mg/kg and as high as 1.0 mg/kg, which is 2 to 5 times of the national limit.