"Underground workers", alert to the "invisible killer" in the mine - radon

A | What is radon?

Radon, chemical symbol Rn, atomic number 86, is a colorless, odorless natural radioactive inert gas produced by the decay of uranium radium. Radon is soluble in water, organic solvents and other liquids, and has a high affinity for fat.

In nature, radon has three important radioisotopes, namely 222Rn, 220Rn and 219Rn, which have half-lives of 3.82d, 55.65s and 3.96s, respectively. It can be seen that the half-life of 220Rn and 219Rn is very short, which means that their radioactivity intensity is reduced to half of the original in a very short time, so we often say that radon refers to 222Rn.

Radon can undergo alpha decay, and the decay products include 218Po, 214Pb, 214Bi and 214Po, which are called radon daughters. The half-life of radon daughters is very short, ranging from 26.8min to 164us, and finally decaying to a stable 206Pb. In the air, the radon daughters are mostly aerosols, have strong adhesion to substances, and are easy to adsorb and bind with mine dust.

Ii | Sources of radon in mine

Radon is the radioactive decay of uranium-radium. And the earth's crust contains uranium. Therefore, in uranium mines and mines with uranium-radium symbiosis, there are widespread hazards of radon and its daughters. In mines, radon and its daughters constantly precipitate from exposed surfaces, rock cracks, caved rocks and groundwater. If the concentration is higher than the national standard, it will endanger the health of miners.

Three | the harm of radon to human body

Radon is a radioactive gas that enters the body through the respiratory tract and is deposited in the lungs. The alpha particles produced by radon decay have a strong ionizing ability, which can destroy cell DNA and damage lung cells, thus inducing lung cancer. Radon has a strong lipophilicity and can cause damage to the nervous system. In addition, high concentrations of radon can also cause changes in the body's blood cells. According to statistics, the dose contributed by radon daughters to the human body is 18.9 times greater than the dose contributed by radon to the human body. Therefore, the harm of radon daughters accounts for the main part. Studies have shown that radon and its progeny and smoking have a combined effect on the occurrence and development of lung cancer. Radon is the second leading cause of lung cancer after smoking. The International Agency for Research on Cancer (IARC) classifies radon as a Group I carcinogen. Lung cancer caused by high radon occupational exposure in miners is included in the range of occupational radiation diseases in China.

Four | How to protect against radon?

Because radon cannot be sensed, it can only be measured by professional instruments. In addition, the harm caused by radon is relatively slow to hide, taking 10-30 years to appear. Therefore, some mines lack sufficient understanding of the harm of radon. The concentration of radon in some workplaces is too high, exceeding the national standard, and miners are exposed to high radon radiation for a long time. Therefore, occupational radiation protection of miners is of great significance.

The employer is responsible for the prevention and treatment of occupational diseases. Mining employers should first perform their protective duties and take measures to prevent and control occupational radon exposure hazards.

▶ To establish a sound radon protection management system, equipped with personnel responsible for protection work, strengthen protection management.

▶ To carry out occupational health education for miners, improve miners' awareness of radon hazards, and enhance individual protection awareness and ability.

▶ It is necessary to develop a radon monitoring system, carry out workplace radon testing and personal radon monitoring, and control workplaces that exceed national standards.

▶ Occupational health monitoring of miners, timely detection of abnormal conditions.

▶ A very important control measure is to reduce the radon concentration under the mine. It includes plugging and sealing the channels and voids that radon enters the workplace from surrounding rock and goaf, preventing groundwater infiltration, timely cleaning up accumulated ore, and adequate ventilation to inhibit radon precipitation and reduce radon accumulation. If radon concentration is difficult to reduce, miner rotation should be arranged to reduce exposure time.

● Tips

Everyone is the first person responsible for their own health. To protect against radon exposure, miners should start themselves. Miners should abide by the radon protection system, according to the requirements of occupational health inspection and personal monitoring, participate in occupational health education and training, improve the level of self-protection. Miners do not eat at work. After each well, take a bath in time and change clothes to reduce the spread of pollution. To reduce the combined effects of radon and smoking on health, miners should quit smoking.