Patient's question:
My friend said it might affect fertility. Is that right? Please elaborate. Thank you.Doctor's answer:
Hello! Research Progress on Occupational Hazards of Welding Operations1. Hazardous Factors and Influencing Factors of Welding Operations
There are many health hazards associated with welding operations, which can generally be categorized into physical and chemical factors. The former includes ultraviolet and infrared rays generated by high-temperature electric arcs. The latter consists of various components of welding fumes, including solid elements such as various metals (iron, manganese, aluminum, chromium, lead, nickel, and radioactive elements), as well as gaseous components like manganese oxide, hydrogen fluoride, and nitrogen oxides [1]. High temperatures, vibrations, and noise are less pronounced. Welding fumes have a very high dispersion degree and exhibit significantly higher biological activity compared to other dusts. The composition of welding fumes varies greatly depending on the welding electrodes and methods, and their biological activity also differs [2]. Biological activity is also related to the solubility and freshness of welding fumes.
2. Damage to Workers' Health Due to Welding Operations
2.1 Effects of Welder Pneumoconiosis and Pulmonary Function
During arc welding, the core wire, flux coating, and base metal in the electrodes melt, evaporate, oxidize, and condense under the high temperature of the electric arc, producing large amounts of metal oxides and other substances as smoke. Long-term inhalation can lead to welder pneumoconiosis. Welder pneumoconiosis typically occurs under closed, poorly ventilated working conditions, with an average onset latency of about 18 years [3]. Pulmonary function tests indicate that exposure to welding dust can cause certain degrees of pulmonary ventilation function impairment in welders, with significant reductions in FVC, FEV1.0, FEV1.0%, MMF, V50, V25, and PEFR [4]. Smoking and dust exposure may have a synergistic effect on pulmonary ventilation function in welders. The impairment of pulmonary ventilation function in welders tends to worsen with prolonged dust exposure [5].
2.2 Manganese Poisoning
All welding materials and electrodes contain varying amounts of manganese. The manganese content in the core wire is generally low, only about 0.3–0.6%. However, to enhance mechanical strength, wear resistance, and corrosion resistance, the manganese content in electrodes can be as high as 23%. In poorly ventilated environments such as ship cabins, boilers, or enclosed containers, long-term inhalation of manganese-containing fumes can lead to manganese poisoning, characterized by elevated blood and urine manganese levels, and altered neurobehavioral functions [6]. Manganese determination in hair can also serve as an early screening indicator for manganese poisoning [7].
2.3 Welder Fever
Welder fever, also known as welder's heat, is a systemic illness caused by inhaling metal oxides, primarily characterized by sudden fever and increased peripheral blood white cell counts. It typically develops 6–12 hours after exposure to metal oxide fumes, presenting symptoms such as dizziness, fatigue, chest tightness, shortness of breath, and muscle and joint pain, followed by fever and leukocytosis. Severe cases may exhibit chills and shivering.
2.4 Effects on the Nervous System
Numerous studies have shown that welding operations are associated with occupational-related nervous system damage, primarily affecting memory, analysis, and localization functions in information processing. This manifests as abnormalities in neurophysiological, neuropsychological, and neurobehavioral functions [9], closely linked to manganese, aluminum, and lead in welding fumes. Using WHO-NCTB tests, results showed a negative correlation between behavioral function scores and urinary manganese levels [10], suggesting that changes in neurobehavioral function can serve as an early indicator for preventing manganese poisoning [11]. Some foreign studies report that behavioral function scores in welders were even higher than in control groups, possibly due to health effects and work-related skill training [12]. Research has also examined the effects of welding operations on the parasympathetic nervous system [13]. Additionally, foreign studies report an earlier onset age of Parkinson's disease in welders (average 46 years, compared to 63 years in controls), suggesting that welding operations are a risk factor for Parkinson's disease [14].
2.5 Effects on Eyes and Skin
The damage to eyes and skin caused by ultraviolet (UVR) and infrared (IFR) radiation is a significant aspect of occupational hazards from welding operations. Welders frequently experience increased eye symptoms, including photokeratitis, chronic marginal conjunctivitis, conjunctivitis, and lens opacity. The prevalence of chronic marginal conjunctivitis and conjunctivitis tends to increase with longer working hours [15]. Excessive UVR exposure primarily causes photosensitive keratitis. Welder cataracts are associated with IFR exposure. Recent foreign studies indicate that workers exposed to excessive UVR are at risk of developing non-melanoma skin cancer [16] and other chronic conditions such as malignant melanoma of the eye [17].
2.6 Effects on the Reproductive System
Reproductive toxicity outcomes are highly significant, and in recent years, research has been conducted on the reproductive toxicity of welding operations, primarily focusing on semen quality in male workers and reproductive outcomes in female workers. Studies show that female welders experience increased menstrual volume, shorter cycles, prolonged periods, and increased leukorrhea, with higher rates of natural abortion, premature birth, and dysmenorrhea compared to controls [18]. Male welders with manganese poisoning exhibit uniform grayish-white semen with normal pH values, and their average liquefaction time is longer than that of controls. Test results confirm that the average semen volume, total sperm count, sperm viability, and motile sperm rate in manganese-poisoned male workers are lower than those in controls, and their sperm abnormality rate is significantly higher [19]. It is believed that metallic manganese can affect male spermatogenesis, directly toxic to sperm development, and kill sperm, thereby altering semen quality. Foreign studies also report changes in sex hormone secretion and reduced sperm quality in welders, with no impact on the gender ratio of offspring [20].
2.7 Effects on Enzyme and Antibody Levels in the Body
In recent years, many reports have been published on the effects of welding operations on enzyme and antibody levels in workers. Studies show that welders have significantly lower serum total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) levels, while malondialdehyde (MDA) levels are significantly higher, but no dose-response relationship exists [21, 22]. Welders are in a state of oxidative stress with weakened antioxidant capacity, suggesting damage to biological membranes [23]. To investigate the effects of welding fumes on the immune globulin content in the human body, single radial immunodiffusion was used to measure IgG, IgA, and IgM levels in welders and healthy controls. Results show highly significant differences in IgG and IgA levels between the welding group and controls (P < 0.05). Additionally, urinary manganese is correlated with IgG and IgA, with correlation coefficients of r = 0.982 and r = 0.991, respectively [24], suggesting that welding fumes affect immune globulin levels. Heat shock proteins (HSPs) are a group of highly conserved proteins synthesized in response to various stress conditions. Under physiological conditions, they are essential for cell survival, and their increased levels in stress conditions enhance cells' tolerance to damage and stress, protecting tissues and cells from harmful factors and maintaining the body's homeostasis. Using enzyme-linked immunosorbent assays, the antibody levels of HSP65 in welders' plasma were detected. Results show that welders' plasma antibody levels are higher than those in controls (P < 0.05), with an abnormal detection rate of 26.1%. It is believed that welding mixed dust, as a stressor, can induce increased synthesis of HSP65 antibodies in the body [25]. Therefore, welders' plasma HSP65 antibody levels can reflect the extent of harm caused by welding mixed dust.
2.8 Effects on Internal Organs
Ultrasound examinations were conducted to explore the effects of welding on the liver and spleen of workers. Results show that the left liver length, thickness, right liver, and spleen thickness in the welding group are all higher than those in controls, with significant differences. Welding operations cause certain damage to the liver and spleen of workers, which tends to worsen with prolonged exposure [26]. Foreign studies report that the risk of endocrine pancreatic tumors in welders is significantly higher than in the general population [27].
2.9 Effects on Trace Elements in the Body
Reports indicate the use of plasma emission spectrometry to detect five trace elements—manganese, copper, zinc, iron, and lead—in the serum of welders exposed to manganese. Results show that the serum levels of manganese and iron in the exposed group are significantly higher than those in controls (P < 0.01), while copper is slightly higher but without significant differences compared to controls (P > 0.05). In contrast, zinc and lead levels are significantly lower in the exposed group (P < 0.01). Stratified analysis by exposure duration and age in the exposed group shows no statistically significant differences in serum trace elements among groups. Conclusion: Excessive inhalation of manganese can affect the levels of five trace elements—manganese, copper, zinc, iron, and lead—in the body, leading to an imbalance in trace elements and promoting the occurrence of manganese poisoning [28]. Other reports indicate that welders have higher manganese content in red blood cells compared to males, and the changes in copper and zinc levels in red blood cells are positively correlated with manganese [29].
The hazards of argon arc welding are relatively greater than those of stick arc welding but not severe enough to be alarming. Infrared radiation from argon arc welding is about 1–1.5 times higher than that from stick arc welding, while the ultraviolet radiation generated by the arc is about 5–30 times higher. In confined spaces, ozone concentrations can reach dangerous levels. During welding, harmful gases such as carbon dioxide and carbon monoxide, as well as metal dust, are also produced, all of which pose certain hazards to welders. Therefore, proper protection should be taken during welding, with electrode materials preferably chosen to be low in radioactivity, such as thorium tungsten or cerium tungsten. When grinding electrodes, masks and gloves should be worn, and hands should be washed after work. For prolonged welding, regular health check-ups should be conducted, and work should be balanced, much like excessive sun exposure can harm the body.
Photokeratitis
Some workers experience photokeratitis when exposed to welding light during the day, suddenly developing symptoms such as inability to open their eyes at night, severe eye pain, tearing, and redness. This is often a case of photokeratitis. The arc light of welding and gas welding, ultraviolet lamps, intense sunlight on beaches and plateaus, and the reflection of sunlight from snow-covered mountains can all produce large amounts of ultraviolet radiation, causing photokeratitis, particularly in welders. The main manifestations of photokeratitis include pain, photophobia, and difficulty opening the eyes 2–12 hours after exposure to ultraviolet radiation due to damaged corneal epithelium. Patients experience severe eye pain as if sand particles are in their eyes, with blurred vision. Ophthalmological examinations reveal congestion of eyelid skin, redness of the eyes, edema of the conjunctiva and cornea, and desquamation of corneal epithelium. Although photokeratitis can be severe, the prognosis is generally good. During the acute phase, topical anesthetic drops (e.g., 0.5% tetracaine solution) can be used 1–2 times to relieve pain immediately, followed by anti-inflammatory eye drops to prevent infection. With rapid healing of the conjunctiva and corneal epithelium, symptoms typically resolve within 2–5 days. To prevent photokeratitis, welders must wear protective face shields or goggles during operation. Additionally, ultraviolet radiation from the reflection of sunlight in high-altitude, snowy, or desert environments can also cause photokeratitis, requiring the use of protective goggles.