Abstract
Among wide spectrum of biomolecules induced by various stress factors low molecular mass protein called metallothionein (MT) is suitable for assessment of the heavy metal environmental pollution. The aim of this work was to determine the metallothionein and total thiols content in larvae of freshwater midges (Chironomus riparius) sampled from laboratory exposure to cadmium(II) ions and from field studies using differential pulse voltammetry Brdicka reaction. Unique electrochemical instrument, stationary electrochemical analyser Autolab coupled with autosampler, was utilized for the analysis of the samples. The detection limit for MT was evaluated as 5 nM. The larvae exposed to two doses (50 ng/g or 50 μg/g) of cadmium(II) ions for fifteen days under laboratory controlled conditions were at the end of the exposure killed, homogenized and analysed. MT content in control samples was 1.2 μM, in larvae exposed to 50 ng Cd/g it was 2.0 μM and in larvae exposed to 50 μg Cd/g 2.9 μM. Moreover at field study chironomid larvae as well as sediment samples have been collected from eight field sites with different levels of pollution by heavy. The metals content (chromium, nickel, copper, zinc, arsenic, molybdenum, cadmium, tin and lead) in the sediment and or MT content in the chironomid larvae were determined by inductively coupled plasma mass spectrometry or Brdicka reaction, respectively.
Highlights
The on-line monitoring of a specific pollutant can be performed for only a short time interval, the alternative methods for long-term monitoring of pollution are developing
Stationary electrochemical analyser coupled with autosampler – Differential pulse voltammetry
“Introduction” section, level of MT determined in animal blood and tissues is thought to be a marker of heavy metal stress
Summary
The on-line monitoring of a specific pollutant can be performed for only a short time interval, the alternative methods for long-term monitoring of pollution are developing. Various species of plants and animals, which are sensitive to higher levels of pollutants or which can synthesize detectable biomolecules as a response to environmental pollution, have been used to assess the effects of longterm environmental stress [1-8]. Metallothioneins (MT) as a group of intracellular, low molecular mass, free of aromatic amino acids and rich in cysteine proteins with molecular weight from 6 to 10 kDa can be considered members of forementioned thiols biomarkers [10-14]. These proteins are abundant through whole animal kingdom, and they were found in higher plants, eukaryotic microorganisms and some prokaryotes. MT is accumulated in lysosomes and was found in nuclei [15]
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