Welding has those bad health hazards?

There are many health hazards of welding operations, which can generally be divided into two categories: physical and chemical factors. The former has a high temperature arc light produced by ultraviolet, infrared and so on. The latter for the welding aerosol of various components, solid state has a variety of metal iron, manganese, aluminum, chromium, lead, nickel, radioactive elements, etc., the gas phase part of manganese oxide, hydrogen fluoride, nitrogen oxides, etc. [1] and other gases. High temperature, vibration, and noise are not so obvious. The dispersion of welding aerosol is extremely high, and the biological activity is significantly higher than other dusts. Welding rods, welding methods are different, the composition of welding aerosol changes greatly, and the biological activity is also different [2]; biological activity is also related to the solubility and freshness of welding fume. 2, the damage of electric welding operation on the health of workers 2.1 welder's pneumoconiosis and the impact of lung function When electric arc welding, the welding rod in the welding core, flux skin and metal base material in the arc at high temperature melting, evaporation, oxidation, agglomeration, resulting in a large number of metal oxides and other substances in the fume, long-term inhalation can cause welder's pneumoconiosis. Welder's pneumoconiosis generally occurs in confined and poorly ventilated working conditions, and the average age of incidence is about 18 years[3] . Lung ventilation function measurements show that exposure to welding dust can cause a certain degree of lung ventilation function damage in welders, and lung ventilation function indexes such as FVC, FEV1.0, FEV1.0%, MMF, V50, V25, PEFR, etc. are all significantly reduced[4]; the smoking factor and dust catching factor may have a synergistic effect on the lung ventilation function in welders; the lung ventilation function damage in welders tends to aggravate with the prolongation of the dust catching working age[5]. There is a tendency for the lung ventilation function impairment of welders to increase with the prolongation of the dust catching working age [5]. 2.2 Manganese poisoning Various kinds of weldments and welding rods contain varying amounts of manganese, and the general manganese content in the welding core is very low, only about 0.3-0.6%. In order to improve mechanical strength, wear resistance, corrosion resistance and other properties, the use of manganese-containing electrodes, the amount of manganese can be as high as 23%. In poorly ventilated places such as cabins, boilers or closed containers welding, long-term inhalation of manganese-containing fumes can occur manganese poisoning, can be detected in the blood manganese, urinary manganese elevation, neurobehavioral function changes [6], manganese determination can also be used as a manganese toxicity early screening indicators [7] 2.3 Welding fume heat Welding fume heat, also known as welder's heat, is a kind of metal fume heat, caused by inhalation of metal oxides to the sudden increase in temperature and peripheral blood white blood cell count increase as the main manifestation. The main manifestation of the systemic disease of leukocyte count increase, often in the exposure to metal oxide fume 6-12 hours [8] onset, dizziness, fatigue, chest tightness, shortness of breath, muscle and joint pain, and later fever, leukocytosis, the worst have cold, chills. 2.4 Effects on the nervous system A large number of studies have shown that there are neurological damages related to occupational exposure in welding operations, mainly involving the functions of information processing and processing such as memory, analysis and localization, which are manifested as neurophysiological, neuropsychological and neurobehavioral abnormalities [9], which are inextricably linked to the manganese, aluminum and lead in the welding fumes. Using WHO．NCTB test, the total score of behavioral function is negatively correlated with urinary manganese [10], suggesting that the change of neurobehavioral function can be used as one of the early indicators for preventing manganese poisoning [11]. In foreign studies, the total behavioral function scores of welding workers were reported to be higher than those of the control group, and the authors analyzed that it might be due to the health effect of workers and the effect of work-related skill training [12]. The effect of welding operations on the parasympathetic investigative function of workers has also been reported [13]. The significantly earlier age of onset of Parkinson's syndrome in the population of welders has also been reported abroad [14] (mean 46 years old, mean 63 years old in the control group), suggesting that welding operations are one of the risk factors for Parkinson's syndrome. 2.5 Effects on the eye and skin Ultraviolet (UVR) and infrared (IFR) damage to the eye and skin is an important aspect of occupational damage in welding operations. A significant increase in ocular symptoms among welders is often reported, manifested as electro-optical ophthalmia, chronic blepharitis, conjunctivitis, and crystalline clouding, etc., and the prevalence of chronic blepharitis and conjunctivitis tends to increase with the increase in the age of the worker [15]. The main damage of excessive UVR exposure is photosensitive keratitis, and cataracts in welders are related to infrared exposure. Recent studies abroad have shown that workers exposed to excessive UVR are at risk of developing non-melanocytic skin cancer [16] and other chronic diseases such as ocular malignant melanoma [17]. 2.6 Effects on the reproductive system Reproductive toxicity is of great significance in terms of outcome, so in the past 10 years a number of studies have been carried out at home and abroad on the reproductive toxicity of welding operations, mainly related to the quality of semen of male workers, the reproductive outcome of female workers and the mechanism of damage. Studies have shown that female welding workers have increased menstrual flow, shortened cycle, prolonged menstrual period, increased leukorrhea, spontaneous abortion, premature birth, dysmenorrhea, all higher than the control group [18]. Manganese-poisoned male workers' semen had a homogeneous grayish-white appearance, normal pH, and the average liquefaction time was prolonged compared to the control group. The test results proved that the average ejaculate volume, total sperm count, sperm survival rate and active sperm rate of manganese-intoxicated male workers decreased compared with the control group, and the sperm malformation rate of manganese-intoxicated male workers was significantly higher than that of the control group [19]. It is believed that manganese metal can affect the spermatogenic system of male workers, have a direct toxic effect on the development of spermatozoa, and kill spermatozoa, thus causing changes in the quality of male semen. Altered sex hormone secretion and decreased sperm quality have also been reported in foreign countries in workers of electric welding operations, but there is no effect on the sex ratio of offspring [20]. 2.7 Effects on the levels of enzymes and antibodies in the body In recent years, there have been many reports on the effects of electric welding operations on the production of enzymes and antibodies in the body of workers. Studies have shown that total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) in the serum of electric welders decreased significantly, and malondialdehyde (MDA) levels increased significantly, but there was no dose-effect relationship [21, 22], and electric welders were in a state of oxidative stress, with a weakened antioxidant capacity suggesting that biofilms were damaged [23]. To investigate the effect of welding fumes on human immunoglobulin content, one-way immunoagar diffusion method was used to determine the immunoglobulin content in welders and healthy controls, respectively