Occupational Risk and Relationship between Chromium and Nickel in Metalworking Fluid with Chromium and Nickel Levels in Blood and Urine among Machinists in Negeri Sembilan, Malaysia.

Application of metalworking fluids produce aerosol that contain metal, chemical residues or physical contaminants which will disperse into the surroundings during the machining operation. The aim of the study was to determine the correlation between chromium and nickel exposure with chromium and nickel levels in urine and blood among workers in the machining industry. This cross-sectional study was conducted with 138 male workers. Urine and blood samples were collected to analyse the chromium and nickel concentrations and a self-constructed questionnaire were given out. Environmental and personal air concentrations were measured using the personal inhalable aerosol sample (SKC). There were significant correlations between personal air chromium with blood chromium (p=0.021) and urine chromium (p=0.04). There was also a significant correlation between individual nickel in air and blood nickel (p=0.018). There were significant relationships between blood chromium with personal air chromium (p=0.012) and employment years (p=0.044). In addition, there was a significant relationship between blood nickel and personal air nickel (p=0.024). There was als a significant relationship between personal air chromium and number of machines used in each section (p<0.001). Linear regression also showed there was a significant relationship between urine chromium with personal air chromium (p=0.04). Both of the studied heavy metals were carcinogenic. The Hazard Quotient (HQ) for concentration of chromium (HQ= 214 x 103) and nickel (HQ= 3.71) in the air signifies a hazardous condition and categorised as an unacceptable risk for a non-carcinogenic health effect by the U.S. EPA (HQ>1)