Several studies have demonstrated the influence of parameters and shielding gas on metal transfer stability or on the generation of fumes in MIG/MAG welding, but little or nothing has been discussed regarding the emission of toxic and asphyxiating gases, particularly as it pertains to parameterization of the process. The purpose of this study was to analyze and evaluate the effect of manufacturing aspects of welding processes (short-circuit metal transfer stability and shielding gas composition) on the gas emission levels during MIG/MAG welding (occupational health and environmental aspects). Using mixtures of Argon with CO2 and O2 and maintaining the same average current and the same weld bead volume, short-circuit welding was performed with carbon steel welding wire in open (welder’s breathing zone) and confined environments. The welding voltage was adjusted to gradually vary the transfer stability. It was found that the richer the composition of the shielding gas is in CO2, the more CO and CO2 are generated by the arc. However, unlike fume emission, voltage and transfer stability had no effect on the generation of these gases. It was also found that despite the large quantity of CO and CO2 emitted by the arc, especially when using pure CO2 shielding gas, there was no high level residual concentration of CO and CO2 in or near the worker’s breathing zone, even in confined work cells.
Context: Multiple health-promoting effects attributed to the consumption of Moringa oleifera leaves as part of diet. Objective: Study evaluated the effect of Moringa oleifera-based diet on nickel (Ni) - induced hepatotoxicity in rats. Male rats assigned into six groups were given oral administration of 20 mg/kg body weight nickel sulphate in normal saline and either fed normal diet or Moringa oleifera-based diets for 21 days. All animals were sacrificed under anesthesia 24 hours after the last treatment. Results: Exposure to Ni elevated the rat plasma activities of ALT, AST and ALP significantly. The Ni exposure also raised the TAG, CHOL and LDL-C while depleting the HDL-C concentration. Also, Ni exposure raised rat plasma MDA but depleted GSH concentrations. The histopathological presentations revealed inflammation and cellular degeneration caused by Ni exposure. However, M. oleifera-based diets protected against Ni-induced hepatotoxicity by improving the liver function indices, lipid profile as well as restoring cellular architecture and integrity. Conclusion: Study lends credence to the health-promoting value of M. oleifera as well as underscores its potential to attenuate hepatic injury.