As a result of changes in hydrology, the former mesotrophic, shallow lake Naardermeer, has been eutrophicated during the last decades. To compensate for shortage of water, eutrophicated water with different chemical characteristics has been supplied. In order to determine the effects of alkalinity, acidity and external sulphate and phosphorus load on eutrophication processes, developments in water chemistry have been studied in enclosures. A decrease of the phosphorus load of the lake did not improve water quality on the short term. This observation was confirmed by this enclosure experiment. Reduction of alkalinity did improve water quality, particularly by reductions of turbidity and chlorophyll-a content. The significant increase in sulphate load in the water layer led to deterioriation of the water quality and an increased biomass of sessile algae by internal eutrophication, probably as a result of increased sulphate reduction in the sediment. Therefore, it seems that lowering of sulphate concentrations in the inlet water after the removal of phosphorus is necessary to improve the water chemistry. The best option, however, is to restore the former hydrological conditions after which the system will be fed only by seepage of groundwater poor in nutrients and sulphate.

Arsenic, an environmental pollutant, is present in minute but invariable amounts in food, drinking water and ambient air. Izmir is founded on a land of long extinct volcanoes, with vast areas of lava ground suitable for agriculture. It is located at close vicinity to high thermal activity, e.g., hot springs and thermal baths. In the present study, total arsenic level in breast milk was assessed in randomly chosen 35 lactating women of different socioeconomic levels who live downtown in Izmir and in milk of 36 cows grazing on shoulder grass of highways with heavy traffic. Total arsenic was assessed on an atomic absorption spectrophotometer (AA-680 Shimadzu). Mean (± SEM) arsenic was found to be 4.219 ± 0.079 µg L⁻¹ in breast milk, and 4.932 ± 0.38 µg L⁻¹ in cow's milk. Conclusion: in Izmir, arsenic contamination of breast milk was not found so as to be considered noxious for suckling infants, whereas was found relatively higher in cow's milk. It would be prudent to remember breast and cow's milk arsenic contamination in breast fed or milk fed babies living in areas with higher thermal activity or in regions where ground water is with high arsenic content.