https://doi.org/10.15255/KUI.2004.004
Published: Kem. Ind. 54 (3) (2005) 143–148
Paper reference number: KUI-04/2004
Paper type: Review
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Bioavailability of Different Metal Species in Marine Ecosystem and Biomarkers of their Exposure

V. Filipović Marijić and B. Raspor

Abstract

Metals, which are introduced to the coastal areas of the aquatic ecosystem, are distributed between water, sediments and organisms. Determination of metals in every of these aquatic compartments has certain disadvantages. It is important to know, besides total metal concentration, chemical forms of metals and their impact on the organisms, and also complex processes of metal distribution and detoxification within the cells. From the biological point of view there is a difference between essential (necessary for the organisms, like sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), iron (Fe)) and toxic metals (without any biological role and potentially harmful to the organisms, like mercury (Hg), cadmium (Cd), lead (Pb), silver (Ag)). The consequences of metal exposure for organisms depend on the routes of metal uptake, their chemical forms and bioavailability, species biology and their position in the food chain. Concentrations of toxic metals in the water column are very low (<1mg l–1), what describes the name “trace metals”. Therefore, input of even small amounts of metals in the aquatic ecosystem can be harmful. Because of that fact it is very important to define changes in the cell structure and functions by means of biomarkers, as a consequence of exposure to toxic metals. Biomarkers of metal exposure are metallothioneins, low molecular mass proteins responsible for homeostasis of essential and detoxification of toxic metals. Continuous field survey (biomonitoring) of metallothioneins is based on their induction in the presence of metals (Zn, Cd, Cu), assuming the differences between basic and induced metallothionein level are evident. Biomonitoring of metallothionein levels in bivalves and fish of near-shore area of the Adriatic Sea, as an early warning signal of metal exposure, is conducted by the multidisciplinary group of scientists in the Laboratory for Biological Effects of Metals at the Ruđer Bošković Institute.

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Keywords

metals, chemical forms of metals, speciation, metallothioneins, biomarkers