Abstract:
Lead exposure is common in automobile battery manufacture and repair, radiator repair,
secondary smelters and welding units. Urinary Aminolevulinic acid has validity as a surrogate
measure of blood lead level among workers occupationally exposed to lead. This study had
therefore assessed the magnitude of lead exposure in battery repair workers of three transport
service enterprises. To this effect, a cross-sectional study was carried out on lead exposure among
storage battery repair workers between November and May 2005 from Anbasa, Comet and Walia
transport service enterprises, Addis Ababa, Ethiopia. Subjective information from the workers was
obtained by making use of structured questionnaire. Other information was obtained from the
walkthrough evaluation of the repair units. Aminolevulinic acid levels in urine were used as an
index of the exposure. This was coupled to measurements of other relevant parameters in blood and
urine collected from adult subjects working in the repair units as well as age matched control
subjects that were not occupationally exposed to lead. Aminolevulinic acid was determined by
spectrophotometry, while creatinine clearance, serum creatinine, urea and uric acid levels were
determined using AMS Autolab analyser.
Urinary Aminolevulinic acid levels were found to be significantly higher in exposed group (1.6
mg/dl+ 0.2) compared to the non-exposed ones (0.7mg/dl+ 0.1) (p<0.001). Alcohol taking exposed
subjects exhibited a significant increase in urinary aminolevulinic acid levels than non-alcohol
taking ones (p < 0.05). Moreover, urinary aminolevulinic acid levels of exposed subjects increased
with age (p<0.001) as well as duration of employment (p<0.001). Whereas, serum uric acid levels
of exposed subjects was significantly higher than non-exposed ones (p<0.05), no statistically
significant difference had been found in renal indices and other measured parameters between
exposed and non-exposed subjects. From the questionnaire responses and walkthrough
observations, it was known that all the repair units do not implement effective preventive and
control measures for workplace lead exposure. Taken together, these findings indicated that
workers in lead acid battery repair units of the transport service enterprises are not safe from
excessively high lead exposure. Thus, strict enforcement of appropriate and cost-effective
preventive and control measures is required by all the enterprises.
Key words: Lead exposure, Delta-Aminolevulinic acid, renal indices, uric acid, preventive and
control measures