Heavy metal pollution from the air water to the soil industrial city up to several hundred times

From frequent “blood lead incidents” to “cadmium-related storms” that shocked the country, the heavy metal pollution alarms in our country frequently rang.

The reporter of the “Economic Information Daily” learned from the investigations in Hunan, Liaoning, Inner Mongolia and other provinces and regions that China’s heavy metal pollution is being transferred from the atmosphere and water to soil pollution, and that heavy metal pollution in soil has entered a “concentration and prolonged period”, which is healthy for residents and Agricultural products [13.49 0.45% shares bar report] security poses serious **.

Exacerbation of heavy metal pollution in soil In recent years, excessive levels of blood lead and urinary cadmium have been reported. Heavy metal pollution has emerged from industrial shifts to agriculture, from urban areas to rural areas, from surface to underground, from upstream to downstream, and from soil and water pollution to food chain transfer. The gradual accumulation of pollution is entering a burst, chain, and regional outbreak phase.

Huludao City is one of the most heavily polluted areas in Liaoning Province. The Huludao zinc factory located in the southeast of the city is the “heavy-hit area” of heavy metal pollution in the city. Just a few kilometers away from the zinc factory, an unpleasant pungent odour rushes in.

Huo Chunhua, the director of the trade and community of Machen landlord's neighborhood office adjacent to the Zinc Plant, told the Economic Information Daily that the zinc plant was built in 1937. Heavy metal emissions from the zinc plant have caused serious pollution of the surrounding air and soil.

“The most unacceptable is the smoke emitted by zinc plants,” said Huo Chunhua. Although the zinc emissions from zinc plants are much lower than at the peak, the communities are filled with smoke as soon as the smoke is exhausted. "Blue smoke" is still breathless. When it rains, the community can hardly see the road.

What is even more worrying is that heavy metal pollution has begun to shift from air and water pollution to soil pollution.

According to a survey conducted by the Jiusan Institute of Liaoning Province, Liaoning's soil-polluted areas are mainly distributed in heavy industrial cities such as Shenyang, Jinzhou, and Huludao cities and metal mines such as the Caihe lead mine, centered on heavy industrial cities and metal mines, and discharge sewage into rivers. As a link, formed into a piece of soil pollution. Among them, the Shenyang and Jinzhou-Huludao contaminated areas formed by industrial production and smelting industry have a large area of ​​more than 1,000 square kilometers, and are mainly polluted by heavy metals such as cadmium, mercury, lead, and zinc, resulting in high pollution intensity.

The above report points out that due to the closure of smelters in Shenyang and the relocation of industrial companies in recent years, the pollution pressure has eased, and the Huludao region has developed severe environmental pressure because of mining and metal smelting industries.

In the same area as Huludao, there are Hunan's Chang, Zhu and Tan areas.

According to a six-year eco-chemical survey conducted by the Ministry of Land and Resources and Hunan Province, a huge soil of 250 km long and an area of ​​2,058 square kilometers has emerged from the Zhuting section of Zhuzhou in Zhuzhou to the Dongting Lake exit of Chenglingji. Abnormal areas of heavy metal elements, rice, vegetables in the area, and reeds and pupae in water bodies all exhibited excessive levels of heavy metal elements mainly composed of cadmium.

Zhang Jianxin, director of the basic research department of the Hunan Provincial Land and Resources Planning Institute, believes that the heavy metal pollution in the soil has been intensifying due to historical trends.

According to reports, compared with the data obtained by regional geochemical surveys in the 1980s, the area of ​​soil heavy metal pollution in the Changsha, Zhuzhou and Xiangtan regions has now increased by 7 percentage points. According to the survey data of the Subtropical Institute of the Chinese Academy of Sciences, the heavy metal pollution in Hunan has reached 715,000 hectares.

Heavy metal contamination potential hazard "upgrade"

In recent years, the cause of the intensification of soil heavy metal pollution in China has been influenced by objective factors such as the natural environment, and it has also been stimulated by human factors.

Tong Qianming, a researcher at the Institute of Geology of Hunan Province, told the Economic Information Daily that in accordance with current standards in our country, a considerable amount of rice and vegetables in the “granary of Hunan” in the Dongting Lake area has been exceeded.

According to the 2005 early and late rice analysis of Changde, Lintong, Yiyang, Nanxian, Ningxiang, and Miluo in the Dongting Lake area, Tong Qianming found that the average cadmium content of late rice was 0.23 to 0.26 MG/KG. The data showed that the cadmium content of late rice reached 41.67%, and nearly all the vegetables exceeded the standards.

The data of agricultural geological surveys in the Liaohe River Basin in Liaoning Province also showed that the impact of heavy metal pollution on agricultural products security cannot be ignored.

Of the 3,984 heavy metal elements detected, a total of 305 were exceeded, exceeding the standard rate of 7.66%. Excessive levels of cadmium, chromium, and other elements in bulk crops are significant, especially in Shenfu Irrigation Area, Liuye Irrigation Area, and Xinchengzi Irrigation Area. Due to the annual use of urban sewage to irrigate farmland, the problems of land pollution and food exceeding standards are more prominent.

Among them, the vegetables exceeding the standard area are mainly concentrated in the periphery of heavy industrial cities such as Shenyang and Jinzhou. For example, the Hehe vegetable base in Shenyang is seriously polluted by land and groundwater, the agricultural ecological environment is poor, and the quality of vegetables is low.

Analyze the causes of land pollution. The toxic and harmful heavy metal elements are mainly caused by sewage irrigation, atmospheric deposition and fertilization. Comparing the three approaches, the heavy metals brought into the soil by fertilizers are the least, and the differences are not significant in all regions. The heavy metal content brought by atmospheric dry and wet deposition and irrigation water factors is quite different. Especially in the periphery of industrial cities and smelting enterprises, the amount of heavy metals brought into the soil by atmospheric dry-wet settlement and irrigation water factors can reach tens to hundreds of times the amount of fertilization.

Tong Qianming believes that according to the existing survey data, it has been shown that soils and planted crops in some parts of China are already contaminated by heavy metals such as cadmium, but they have not yet reached the level of causing human illness.

However, Tong Qianming pointed out that this does not mean that the prevention and control of heavy metal pollution in the soil can be relaxed. According to the current development trend, if there is slight relaxation, the accumulation of heavy metal pollution in the soil will be further exacerbated after several years. Once the heavy metal content reaches the disease level, the situation will be Will be out of control.

The experts at the local government's one-sided pursuit of GDP have argued that the key to preventing and controlling heavy metal pollution in the soil is to curb the impulse of local governments to pursue GDP growth one-sidedly, compared with the difficulties faced by capital and technology. During the “Twelfth Five-Year Plan” period, China will still be in a period of rapid industrialization and urbanization. If we cannot completely reverse the impulse of some local governments to pursue GDP growth one-sidedly, and prevent the intensification of heavy metal pollution transfer will face a very serious situation.

The main source of heavy metal pollution in China is chemical industry and mining. Since the mid-1980s, the extensive development mode of the domestic mining industry, coupled with the backwardness of science and technology, insufficient environmental protection input and awareness, blind development of resources, and indiscriminate exploitation of Yunnan Lands in major metallurgical areas such as Guangxi, Guangxi, Hunan, Sichuan, and Guizhou have become increasingly polluted.

In the economically developed eastern coastal regions, heavy metal pollution comes from factories. The “2010 IT Brand Supply Chain Heavy Metal Pollution Survey” jointly issued by more than 30 domestic environmental protection organizations stated that IT companies rank first in heavy metal pollution. A soil survey conducted by the former State Environmental Protection Administration showed that nearly 40% of farmland vegetable soil in the Pearl River Delta of Guangdong Province was contaminated by heavy metals, and 10% of them were seriously excessive.

Agriculture and aquaculture have also become sources of heavy metal pollution. Tong Qianming told the reporter of the "Economic Information Daily" that according to the "Ecological and Geochemical Investigation and Evaluation Report of the Dongting Lake Area in Hunan Province", the cadmium input to the soil in six research areas of Ningxiang and Yiyang was analyzed: The cadmium input from irrigation water was approximately Mu 0.013 grams, and from the phosphate fertilizer 0.11 grams per acre, cadmium into the latter than the former more than ten times.

In some small-scale farms, people often add arsenic to pigs, chickens and other farm animals, because this heavy metal can kill parasites in the pig and promote livestock growth. The excrement of these animals is also an organic fertilizer that farmers are willing to purchase. When arsenic-containing fertilizers are deposited in the fields, the heavy metals in the fertilizers will sneak quietly into the ground and be transferred to crops as they are cultivated. People eat the pigs fed with these heavy metal-contaminated feeds and eat the vegetables and grains grown in the soil contaminated by heavy metals. Some even drink groundwater contaminated by heavy metals and the human body is so polluted twice. Even third degree pollution.

In addition, some local governments’ erroneous “concept of development” and “concept of achievement” still hinder the prevention and control of heavy metal pollution.

The Environmental Protection Agency of Hunan Province publicly disclosed in June 2010 that since September 2009, two levels of environmental protection agencies in Hunan and Hengyang have issued eight rectification orders to the city of Fuyang, demanding that Xiangyang City be responsible for its subsidiary Yaotian Town. The enterprises that have hidden dangers of heavy metal pollution in their homes have eliminated or closed down, but eight corrections have not been effectively implemented.