Copper and zinc in four freshwater fish species from Lake Pamvotis (Greece).

Lake ecosystems are vulnerable to heavy-metal pollution. Fish samples are considered as one of the most indicative factors, in freshwater systems, for the estimation of trace metals pollution potential. Lake Pamvotis (NW Greece) is a typical Mediterranean ecosystem of great importance in regard to biodiversity and to aesthetic value. The fish species found most commonly in the lake are Cyprinus carpio, Silurus aristotelis, Rutilus ylikiensis, and Carassius gibelio. The aim of the present study is to evaluate the level of contamination of two essential heavy metals (copper and zinc) appearing at high concentrations in lake water in the above four fish species. Metal concentrations were measured by atomic absorption spectroscopy in three different tissues (muscle, liver, gonads) in order to assess the fish contamination. A two-factor analysis of variance, based on the procedure of general linear models, was employed in which fish species (four levels) and fish tissue (three levels) were examined for potential influence on Cu and Zn concentrations. Differences between level means per factor were treated using Tukey's multiple comparisons of means. The study showed that C. carpio and R. ylikiensis presented the highest metal content. Tissues analysis revealed that liver and gonads accumulated the highest levels of Cu and Zn. Metal concentration in the edible part of the examined fish (muscle) were in the safety-permissible levels for human consumption.

Lead and cadmium in eggs of colonially nesting waterbirds of different position in the food chain of Greek wetlands of international importance.

Lead and cadmium concentrations were measured in eggs of collonially nesting waterbirds with different position in the food chains of Greek wetlands of international importance. Differences were found between species in the levels of both lead and cadmium in the Evros and Axios Deltas attributable to their different diets. Nevertheless, the concentration in eggs was unrelated to the position of each species studied in its food chain. There was no significant difference in lead levels among four wetlands sampled for the cormorant and in Cd levels among three wetlands sampled for the Mediterranean gull, probably implying species-specific accumulation patterns. A higher lead pollution of the Axios Delta area was only reflected in the eggs of the Mediterranean gull. The very low concentrations of both metals found in the eggs may either suggest low environmental inputs or lack of sensitivity in using eggs as lead and cadmium biomonitors, thus a more sensitive bioindicator still remains to be found.

Atrial natriuretic peptide relation to plasma and heart zinc concentrations of Wistar rats exposed to cold and hot ambients.

Plasma atrial natriuretic peptide (ANP) and zinc levels, as well as heart tissue zinc concentrations were determined, in male Wistar rats after the exposure of 114 rats at low temperature (4 degrees C) and 95 rats at high temperature (35-36 degrees C) for 28 d. Plasma ANP was estimated by radioimmunoassay and Zn2+ concentrations by atomic absorption spectrometry. Values were compared to a control group exposed at 20-22 degrees C (76 rats). Plasma ANP and Zn2+ levels, as well as heart tissue Zn2+ concentrations of control rats did not show statistically significant variations during the study, whereas rats exposed to cold and hot ambients showed significant variations of the parameters. A significant increase of plasma ANP and plasma zinc and heart tissue Zn2+ concentrations developed during cold exposure, whereas a gradual decrease of plasma ANP and Zn2+ levels was revealed during hot adaptation. Results also indicate that plasma ANP and zinc levels are proportionally related, whereas there is an inverse relationship between plasma ANP levels and heart Zn2+ concentrations, in both cold and hot exposed rats. In conclusion, our results show that ANP in relation to zinc probably play an important role in cold and hot acclimatization of rats.