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352601 
Journal Article 
Reappraisal of Blood Lead Levels and Relation to Delta-Aminolevulinic Acid Dehydratase, Zinc Protoporphyrin and Urinary ALA Level in Thai Normal Adults and Lead Exposed Workers 
Rujirojkul, W; Boonphakdee, T; Muntanachitra, V; Cheevaporn, V 
2008 
1 
1 
English 
All studied participants of 65 lead-exposed workers and 52 non lead-exposed persons who voluntarily participated and signed consents were interviewed about their working duration, type of work, risk behavior and personal data. Blood and urine samples were drawn for PbB, d-ALAD, ZPP and ALAU analysis respectively. The mean PbB level for workers in lead smelters, 22.4 +/- 17.9 microgram/dl (range 1.3-67.2 microgram/dl) was found higher than that for the non-exposed persons (mean = 5.0 +/- 2.4 microgram/dl, range 2.0-13.2 microgram/dl). In relative to previous studies, mean PbB concentration found in the unexposed persons tended to decreased follows the reduced use of leaded gasoline in 1996 in Thailand. A highly significant negative correlation (R2 = 0.86) was observed between PbB concentration and d-ALAD activities among lead exposed persons. Statistical analysis showed that d-ALAD activities significantly decreased (p<0.05) when PbB level surpassed 10 microgram/dl. ZPP level increases slowly with increasing PbB concentration from 10-40 microgram/dl and can be distinguished from normal when the PbB concentration surpasses 40 microgram/dl. Whereas significant relationship between ALAU levels & PbB concentrations did not observed in lead exposed persons as well as non-lead exposed persons. The mean PbB level of 5.0 +/- 2.4 microgram/dl and range of 2.0-13.2 microgram/dl could be regarded as the current reference values for the general population of the country. Determination of d-ALAD activity in erythrocytes is a useful method for evaluating lead exposure in high blood lead level persons (PbB>10 microgram/dl). ZPP measurement is simple and inexpensive, but less sensitive and could be used for screening only in those high lead contaminated persons (PbB>40 microgram/dl). ALAU measurement cannot be served as early biochemical indices of lead exposure both in lead exposed and non-lead exposed persons. 
Article Subject Terms: Biochemistry; Blood levels; Erythrocytes; Gasoline; Lead; Occupational exposure; Smelters; Urine; Zinc; Article; Taxonomic Terms: Alaus; Article Geographic Terms: Thailand; P 6000 TOXICOLOGY AND HEALTH; EE 10 General Environmental Engineering; H 1000 Occupational Safety and Health