engleski

Determination of dissolved monomethyl mercury in saline, estuarine and fresh waters of Croatia

The measurements of dissolved monomethly mercury (MeHg) (which included both the dissolved part and the part leached from the particles by the addition of a 2M HCl) were carried out in natural waters of various origin and composition (fresh, estuarine saline and brackish water, saline coastal water and groundwater). Following a proper water sampling procedure, MeHg was leached by a hydrochloric acid, preconcentrated on a sulphydryl cotton fibre (SCF), eluated with a hydrochloric acid, decomposed, and detected as Hg0 by a cold vapour atomic absorption spectrometry (CVAAS). The concentrations of MeHg determined in the water samples of the Krka River Estuary, groundwaters (the landfill "Jakuševec", in the vicinity of Zagreb), and the Kaštela Bay were: (0.035-0.75 pM), (0.2-3pM), and (1.0-20 pM), respectively. The concentration of MeHg in the water column of the Krka River Estuary is inversely related to reactive mercury. The maximum of the MeHg is just above a fresh/saline water interface (FSI), whereas the maximums of the reactive and total mercury are below and/or inside the FSI. Winds and other meteorological conditions exert significant influence upon the distribution of the MeHg concentrations in the water column. The performance of the modified analytical procedure was improved yielding a high recovery efficiency of MeHg (85-96%), reproducibility better than 15% (CV) and the limit of detection of 35 fM, i.e. 0,007 ng L-1 (3 ? of the blank) for 3L of water sample.

speciation; mercury; dissolved monomethyl mercury; estuarine waters; seawaters; groundwaters

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