1,2-Dihydroxynaphthalene as biomarker for a naphthalene exposure in humans

Objectives: The possibly carcinogenic properties of naphthalene are, regarding to its ubiquitary presence, of environmental-medical and occupational-medical importance. Seven isomeric dihydroxynaphthalenes (DHN) were examined for their suitability as biomarkers in human biomonitoring and to get insights in human naphthalene metabolism. Methods: We developed a GC-MS-method for the quantification of 1,2-, 1,4-, 1,5-, 1,6-, 1,7-, 2,6- and 2,7-DHN after solid phase extraction and derivatization with BSA/TMCS. The internal burden of DHN after exposure to naphthalene was determined by measuring urine collected from smokers and non-smokers among the general population and among occupationally exposed persons. Results: The elaborated method can be regarded as specific and sensitive procedure to quantify the seven different DHN. In human urine, we detected 1,2-DHN as main metabolite in 54 of the 55 analysed samples. Median 1,2-DHN values (range) were 1012 mu g/L (22-6477 mu g/L) for workers and 8 mu g/L (