Quantification du mercure dans des échantillons de l'herbier Tourlet et mesures d'imprégnation des personnels impliqués dans sa restauration

Abstract

Until the 1980s, most of herbarium specimens were protected from bacterial, fungal and insect degradation using a treatment called "corrosive sublimate", a solution of chloride of mercury. We present here a study carried out on the 19th century "general herbarium" of the botanist pharmacist Ernest Henry Tourlet. This herbarium contains about 17 000 parts of Angiosperms, Gymnosperms and Pteridophytes from France, Europe and the European colonies collected in the 19th century or taken from older herbaria. The herbarium had been protected by mercuric chloride. This herbarium is currently being restored in the Faculty of Pharmacy of Tours. During this operation, we quantified mercury concentrations in plant specimens and herbarium sheets. The analyses have been performed first qualitatively by X-ray fluorescence spectroscopy, then by ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). We also quantified the concentration of mercury in the urines of the two employees restoring the herbarium (one of them for 6 years, the other for 2 years). The results indicated an important variability of mercury concentrations across the samples; one specimen (no 2) presented an abnormal concentration of more than 70 mg/gr. of dry matter The results shows that, occasionally, high concentrations can be found in some of the specimens handled. The results of the analysis of the urine of the persons in charge of the restoration of the herbarium show low values of mercurecreatinine ratio: 1,9 μgr. per gr. of creatinine for the employee with the longest exposure, less than 1 μg for the other. Copyright © 2012 Société botanique de France.