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Cytotoxic effects of four types of welding fumes on macrophages in vitro: a comparative study
Abstract:
The effects of fume particles given off by the manual metal arc (MMA) and metal inert gas (MIG) welding of stainless steel (SS) and mild steel (MS) were studied on rat alveolar macrophage cultures in vitro. The fumes were generated by welding, and particulate material obtained was collected on membrane filters. The macrophage cultures were exposed to the total dust and to its water-insoluble fractions. Cell variability and the release of both lactate dehydrogenase and one lysosomal enzyme from the cells to the medium were measured after an exposure period of 24 h. The cytotoxic control dust was DQ 12 quartz, and the inert control dust was pure titanium dioxide. According to the parameters studied, SS/MMA and MS/MMA welding fumes were cytotoxic to rat alveolar macrophages. The cytotoxic effect of SS/MMA welding fumes decreased after the samples had been washed with phosphate-buffered salt solution. The MIG welding fumes of SS and MS had markedly smaller effects on the cells. Diluted solutions of potassium chromate were also tested in order to investigate its role in the cytotoxicity of SS/MMA welding fumes. The results suggest that hexavalent chromium may be responsible for the cytotoxicity of SS/MMA.
Insights
Manual metal arc (MMA) welding fumes from stainless steel (SS) and mild steel (MS) are cytotoxic to rat alveolar macrophages. Hexavalent chromium in SS/MMA fumes may be responsible for this toxicity.
Area of Science:
- Occupational Health
- Toxicology
- In Vitro Studies
Background:
- Welding processes generate fumes containing metal particles.
- Exposure to welding fumes can pose risks to respiratory health.
- Alveolar macrophages are key immune cells in lung defense.
Purpose of the Study:
- To investigate the in vitro cytotoxic effects of welding fumes from stainless steel (SS) and mild steel (MS) on rat alveolar macrophages.
- To compare the toxicity of fumes generated by manual metal arc (MMA) and metal inert gas (MIG) welding.
- To explore the potential role of hexavalent chromium in the observed cytotoxicity.
Main Methods:
- Rat alveolar macrophage cultures were exposed to welding fumes (total dust and water-insoluble fractions).
- Cytotoxicity was assessed by measuring cell viability, lactate dehydrogenase release, and lysosomal enzyme release.
- DQ 12 quartz and titanium dioxide were used as cytotoxic and inert controls, respectively.
- Potassium chromate solutions were tested to evaluate the role of hexavalent chromium.
Main Results:
- Manual metal arc (MMA) welding fumes from both SS and MS demonstrated significant cytotoxicity to macrophages.
- The cytotoxic effect of SS/MMA fumes was reduced after washing with phosphate-buffered saline.
- Metal inert gas (MIG) welding fumes exhibited markedly lower toxicity.
- Results suggest hexavalent chromium is a likely contributor to the cytotoxicity of SS/MMA welding fumes.
Conclusions:
- MMA welding fumes, particularly from stainless steel, are cytotoxic to alveolar macrophages in vitro.
- Hexavalent chromium is implicated as a primary agent responsible for the observed cytotoxicity of SS/MMA welding fumes.
- MIG welding fumes appear to be less hazardous to macrophages compared to MMA fumes.