Biomonitoring of Heavy Metals among Nielloware Workers in Nakhon Sri Thammarat Province

Abstract

Objective: To determine lead and mercury concentrations in biological samples from nielloware workers, to describe the association between occupational lifestyle, work position, work environment, behavioral factors, acute and chronic neurological symptoms, and levels of metals in biological samples. Material and Method: A cross-sectional study was conducted by interviewing 45 nielloware workers and 45 matched nonexposed persons living in the municipality of Nakhon Si Thammarat Province, Thailand. Blood and urine samples were collected to determine lead and mercury concentrations by atomic absorption spectrophotometer. Results: The blood lead levels (7.30 μg/dl) and urinary mercury levels (3.30 μg/g creatinine) of the nielloware workers were significantly higher than the control group (p < 0.001). Income, working environmental conditions, work position, duration of work, personal protective equipment (PPE) and personal hygiene, had significant associations with blood lead and urinary mercury levels (p < 0.05). A significant positive correlation was found between income and blood-lead level (r = 0.968, p < 0.001) and urinary-mercury level (r = 0.661, p = 0.004). The nielloware workers developed acute and chronic symptoms, such as headaches, rash, fatigue, tightness in the chest, loss of consciousness, abnormal tiredness and headache at least once a week and those who developed symptoms had significantly higher heavy metal levels than those who did not at p < 0.05. Conclusion: The blood lead and urinary mercury levels in nielloware workers were significantly higher than those in the control subjects. The significant associations were found between income, work position, PPE and personal hygiene and blood lead and urinary mercury levels.