Assessing the environmental/human risk of potential genotoxicants in water samples from lacustrine ecosystems: The case of lakes in Western Greece.

Lakes, representing major freshwater resources, play a crucial role for both humans and ecosystems. Based on the increasing international interest in the contamination of water resources by genotoxic compounds, the present study aimed to evaluate the genotoxic potential of surface water samples collected from the five (5) lakes (Amvrakia, Lysimachia, Ozeros, Trichonida, Kastraki) located in Aitoloakarnania regional unit (Western Greece). The genotoxic potential of surface water samples was evaluated by employing the Cytokinesis Block MicroNucleus (CBMN) assay in cultured human lymphocytes. In the former assay, lymphocytes were treated with 1, 2 and 5% (v/v) of surface water from each lake. Statistically significant differences (1.7 to 3.3 fold increase in MN frequencies vs. the control) were seen at the dose of 5% (v/v) in all studied lakes. At the dose of 2% (v/v) statistically significant differences (1.7 to 2.6 fold increase in MN frequencies vs. the control) were observed in all studied lakes except Trichonida lake. Finally, at the dose of 1% (v/v) statistically significant differences (2.3 and 2.5 fold increase in MN frequencies vs. the control) were observed in the Ozeros and Lysimachia lakes. The evaluation of the potential genotoxic effects and the analysis of the physicochemical parameters of lakes' surface water samples is a first step in our effort to evaluate the water quality, in terms of the presence and environmental/human risk of genotoxicants in the studied lake ecosystems. The present study showed for the first time the presence of genotoxic substances in surface waters of the studied lakes.

Temporal and spatial distribution of physico-chemical parameters in an anoxic lagoon, Aitoliko, Greece.

Temporal and spatial distribution of physico-chemical and water quality parameters and their correlation with meteorological and hydrological data, was investigated for anoxic lagoons, in Greece. Monthly variations of parameters like temperature, salinity, dissolved oxygen, chlorophyll-a, total phosphorus etc., along the Aitoliko lagoon water column, were recorded and studied at 14 stations. Throughout the sampling period, in lagoon's water column three layers were determined: the surface low density layer (11.49-16.15), the layer with the steep density gradient and the deep dense (19.78-20.62) water below the depth of 20 m. The depth of the surface and pycnocline layers depends on seasonal surface salinity (20.53-22.43 per hundred) and temperature (12.48-28.40 degrees C) alterations. Lagoon's monimolimnion was extended, below the depth of 20 m and had constant temperature and salinity equal to about 13 degrees C and 27 per hundred respectively. Meteorological conditions control temperature (R2=0.845) and dissolved oxygen (R2=0.576) monthly changes, in lagoon's epilimnion, while salinity seems to be related with the salt/fresh water budget into Aitoliko lagoon. Epilimnetic chlorophyll-a (3.29-14.89 microg l(-1)) and total phosphorus (13.33-36.31 microg l(-1)) concentrations classify Aitoliko lagoon as a mesotrophic environment (40

A theoretical and experimental physicochemical study of sulfur species in the anoxic lagoon of Aitoliko-Greece.

The spatiotemporal changes of metals, inorganic ions and physiochemical parameters of Aitoliko lagoon, an anoxic wetland in Western Greece, were studied with special emphasis in sulfur species. Theoretical physicochemical modeling was performed for the sulfur speciation, based on experimental pH and redox potential data. Accordingly, the speciation of sulfur in the lagoon can be operationally divided in two domains: (a) for depths d = 0-10 m below the surface, the sulfur speciation can be described by equilibrium reactions between the aqueous species. (b) At depths d > 10 m a progressive decline for SO4(2-) concentration is observed between theory and experiment. At the lagoon-bottom an elevated concentration of 19+/-2 mM SO4(2-) was measured, which cannot be described by physicochemical equilibrium based on the pH, E(h), O2 concentrations measured in situ. Accordingly, we suggest that additional biogeochemical processes, such as sulfur bacteria activity, have to be invoked. Of particular importance is that the experimental pH-pe values cross the critical region where the interplay of SO4(2-)/S2(-)/H2S occurs. This explains why a relatively small fluctuation of pH, pe values may result in a shift of the equilibrium over one sulfur species. This explains the, otherwise accidental, previously reported releases of H2S in the air over the lagoon.