Mise au point et validation d’une méthode de dosage de l’acide delta-amino levulinique urinaire et son application dans le suivi de travailleurs exposés au plomb

Abstract

Lead is one of the most widely used metals by humans, particularly in battery manufacturing. However, this sector is associated with significant occupational exposure, resulting in detrimental effects on various biological functions. Among the indicators of this metal's effects is delta-aminolevulinic acid (ALA) in urine, a very good marker of the effects on the body during occupational exposures. In this study, we appreciated the importance of measuring urinary ALA and its role in biological monitoring. Subsequently, we developed and validated a method for measuring this acid in urine to allow for better monitoring of workers exposed in a lead manufacturing and recycling plant. The main objective of this study is to validate a spectrophotometric method for measuring ALA-U. Following the analytical validation of the method we conducted according to the SFSTP 2003 guide at the Toxicology Laboratory of the Sétif University Hospital, the technique is perfectly linear in the concentration range from 5 mg/L to 40 mg/L. The intra- and inter-day repeatability results are excellent. The method is specific, sensitive, and accurate (recovery and bias meet requirements). We set a secondary objective: the evaluation of urinary ALA levels in workers at the battery factory, but unfortunately, we were unable to recruit them due to the COVID-19 pandemic health protocol. Nevertheless, we studied the correlations between urinary ALA levels and blood lead levels in workers already recruited by our colleagues the previous year, in a statistical study for a final-year thesis. Furthermore, correlations with hematological parameters (Hb level, MCHC, MCHC, red blood cell count, MCV)