Effect of Occupational Exposure to Lead on Liver Function Parameters

Lead a divalent cation has long been recognized as an ubiquitous pollutant of the eco-system. Occupational exposure to lead is the most common cause of elevated blood lead levels, (BLL). Occupational exposure to lead has been associated globally with adverse health effects. This study was designed to ascertain if some occupational exposure to lead in Nigeria results in elevated blood lead levels and impairment of liver function. A total of eighty –six (86) adult Nigerians who were occupationally exposed to lead were used in the study. They consist of thirtytwo (32), mechanics, thirty (30) panel beaters and twenty-four (24) mixed population comprising of petrol attendants, battery chargers and motorcycle riders grouped as “others”. The control subjects, who were not in any way occupationally exposed to lead were (30) thirty in number. The BLL were assayed using atomic absorption spectrophotometer (AAS). The biochemical indices for liver function were assayed by standard methods. The results obtained show that occupationally exposed subjects had significantly elevated BLL compared to controls (Test subjects 69 .79 + 62.30μg/dl, control: 1.98 + 3.85μg/dl). The occupationally exposed subjects had significantly higher prevalence of lead toxicity, (57%), against the controls (0%; P= 0.05). The highest prevalence of lead toxicity was found in the test subjects grouped. “others”. The activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) in mechanics were 48.80±24.0, 69.40±30.90 and 57.70±28.0i.U/L respectively), panel beaters, (43.80±17.50, 72.50±29.0 and 75.0±27.80i.U/L respectively) and “others”, (32.80±26.20, 38.50±27.10, and31.10±17.0i.U/L respectively) and were significantly elevated compared to controls (19.0±4.90, 23.40±7.10 and25.40±11.50i.U/L respectively ; p<0.0001). There were no mean significant changes in the serum levels of total protein, albumin, conjugated and total bilirubin in exposed subjects compared to controls (p>0.05). From these findings it is concluded that occupational exposure to lead in Nigeria is associated with significant elevation of BLL, increased prevalence of lead toxicity and liver dysfunction.