Simple method for monomethylmercury determination in estuarine sediments

• DOI: 10.1016/j.trac.2004.08.009
• Publication Date: 2004-11-06T13:03:10Z
• Authors: J. Canário; P. Antunes; J. Lavrado; C. Vale
• Keywords: 01 natural sciences; 6. Clean water; 0104 chemical sciences; 0105 earth and related environmental sciences

Several analytical methods have been proposed for determining monomethylmercury concentrations in sediments. We give an overview of the methods frequently used in the last few years, including matrix digestion, solvent extraction and preconcentration steps prior to quantification of MMHg by instrumental analysis. We propose a simple method to determine MMHg in estuarine sediments, involving alkaline digestion (KOH/methanol), toluene extraction and preconcentration of MMHg in dithizone. We performed separation as well as quantification by gas chromatography electron capture detection. Obtained and certified MMHg concentrations for international certified reference materials (AIEA-405 and CRM-580) showed no statistically differences (α=0.05). Low limits of detection, good repeatability and recoveries made this method a useful tool for rapid analyses of estuarine sediments. We applied this method to a sediment core collected in the Tagus Estuary, Portugal, giving a rapid vertical distribution of MMHg concentrations.