Monitoring of Environmental Mercury Exposure Using Hair as Bioindicator and the Study of Potential Factors Affecting on It in Karachi

The World Health Organization (WHO), Environmental Protection Agency (EPA), and International Atomic Energy Agency (IAEA) have recommended the use of hair for worldwide environmental monitoring. Mercury exposure to the inhabitants of Karachi was assessed by using hair as bioindicator. Hair samples of 200 residents of Karachi were collected and analyzed through cold vapor atomic absorption spectroscopy (CVAA) technique for mercury concentration. The effects of age, gender, working status, location, food and smoking habit were investigated. Control region showed a positive correlation between HHg and age of donor while no such correlation was observed for polluted regions. Mercury exposure through cosmetic usage in female was only pronounced in control region. These results indicate that environmental pollution dominates other potential factors. Age and smoking habit were not found to be the influencing factors while an elevated mean level of mercury was noticed for regular fish consumers than rarely fish consumers. 95.33% of the samples contained HHg greater than the permissible level of 2 μg∙g set by WHO. An apparently healthy male donor had HHg concentration (28.24 μg∙g) closer to the high risk concentration of 30 μg∙g based on WHO criteria. Whereas, two female donors of the age group of 41 50 years had HHg concentrations (10.82 and 11.84 μg∙g) higher than the NOAEL (no observed adverse affects level) value (10 μg∙g) for females which is associated with fetus neurotoxicity. However, no symptoms of mercury toxicity were visible. The results indicate the alarming condition of pollution in the city which should be taken into further consideration.