From: Lead exposure study among workers in lead acid battery repair units of transport service enterprises, Addis Ababa, Ethiopia: a cross-sectional study
Employment duration
δ-ALA (μg/ml) ± SEM
≤ 10
5.4 ±1.6
11–20
14.5 ± 3.1
21–25
19.0 ± 3.7
25+
23.4 ± 3.5