The delta-aminolevulinic acid dehydratase (ALAD) enzyme of a novel record for Turkish microbial flora was studied. The isolate I-113 was obtained from Tuz Lake in Turkey and identified as Haloarcula argentinensis. The ALAD enzyme of the isolate was assayed in order to determine its requirements and to be used as biomarker for lead pollution in it's ambient. In enzymic studies, the effects of various metals (Cd, Co, Mg, Mn, Ni, Pb, and Zn), pH (3-11), temperatures (25-55 degrees C), and salinity (15-25%) conditions have been examined. The data obtained from the studies were analyzed statistically by using Kruskal-Wallis, Mann-Whitney, correlation, regression, variance analysis, and significance tests were performed by using SPSS 10.0 for Windows. Although its optimum pH was determined as 7, it was still active at pH 3-11. The optimal temperature for the enzyme was observed to be 30 degrees C. Mn and Pb inhibited its activity significantly (p < 0.05) while Zn increased it slightly. The ALAD enzyme in H. argentinensis could be used as a biomarker for Pb contamination.