Distribution of organic and inorganic mercury in the tissues and organs of fish from the southern Baltic Sea

Lucyna Polak-Juszczak

doi:10.1007/s11356-018-3336-9

Abstract

The aim of this study was to determine the distribution of total mercury (THg), methylmercury (CH3Hg+), and inorganic mercury (Hginorg) in the tissues and organs of fish depending on species, tissue, and organ, and their bioaccumulation in tissues and biomagnification throughout the trophic web. The study included four species of fish (herring, sprat, cod, and eel) from the southern Baltic Sea. The concentrations of the different forms of mercury were determined in tissues and internal organs. Intra-specific differences in levels of THg, CH3Hg+, and Hginorg in the tissues and organs were determined. Muscle contained the highest proportions of THg and CH3Hg+ in comparison to that in the internal organs. Differences in concentrations of THg, CH3Hg+, and Hginorg in the tissues and organs of fish were related to their preferred prey. The bioaccumulation of CH3Hg+ in the tissues and organs of predatory fish at the highest trophic levels was greater than in the liver and digestive tract of fish species at lower trophic levels, in which Hginorg predominated. The high concentrations of CH3Hg+ in eel and cod and the low levels in herring and sprat were linked with their food and the transfer of this element among species. The results suggested that the type of food, feeding habits, and trophic position were important parameters that influenced the transfer and biomagnification of mercury in fish.

Highlights

Mercury is recognized as a major environmental pollutant and a hazardous metal for living organisms
The paper presents the measurements of THg, CH3Hg+, and Hginorg concentrations in the tissues and organs of four fish species from the Baltic Sea
The mercury and methylmercury concentrations were tested for normality (Shapiro-Wilk test)

Summary

Introduction

Mercury is recognized as a major environmental pollutant and a hazardous metal for living organisms. Mercury bioaccumulation in the aquatic food web extends from its base of microorganisms and plankton to predatory fish and mammals at the top of the food chain. Fish take up mercury by absorbing it through the body surface and gills, but the primary source is the diet (Hall et al 1997; Jaeger et al 2009). Feeding habits of fish species (piscivorous, omnivorous, non-piscivorous) impact mercury levels in tissues and organs (Garcia et al 2000; Berntssen et al 2003). Mercury taken up from the water through the gills and skin is primarily Hginorg since this form dominates in water and sediments. Inorganic mercury contained in the sediments is transformed by microbes such

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