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The effects of marine aquaculture on the environment were evaluated by studying the water quality of Güllük Bay (Turkey). Marine aquaculture, both extensive and intensive, is one of the most important activities carried out in this area. The intensive culture of fish (Dicentrarchus labrax) is the most important polluting element in Güllük Bay. Records of long term (seasonally) monitoring of the ambient water dissolved oxygen concentration, the inorganic nutrients (ammonia, nitrate, nitrite, and phosphate) and chlorophyll a concentrations were generated to assess sea water quality of Güllük Bay. Surface water (0.5 m) samples were collected from seven fish farm areas in the cage of Güllük Bay (here after reported as the cage stations). Reference surface water was also concurrently sampled at three stations. Modifications in the cage stations water quality were assessed as the difference between the magnitude of a specific parameter recorded at cage station and the concurrently recorded value of the parameter at the reference station, relative to the mean value at the reference station. In this study, results in the specific modifications are discussed at the study period. An aquaculture area had consistently positive modifications in phosphate concentration, but not in nitrogen or chlorophyll a concentrations. Chlorophyll a concentrations showed non positive modifications only in June. In addition to these site specific modifications nitrogen concentrations were positively modified in August and October.

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Seasonal variation of the concentrations of trace metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were measured by ICP-AES in the water and sediment from the Saricay Stream, Geyik Dam and Ortakoy Well in the same basin. Comparisons between trace metal concentrations in water and sediment in three sources (Stream, Dam and Well) were made. The concentrations of a large number of trace metals in the water and sediment were generally higher in the Stream than in the Well and Dam, particularly in summer. Trace metal concentration ranges in sediments of the Saricay Stream and its sources showed very wide ranges (as mass ratio): Co: 5-476 microg g(-1), Cr: 15-1308 microg g(-1), Cu: 7-128 microg g(-1), Fe: 1120-13210 microg g(-1), Mn: 150-2613 microg g(-1), Ni: 102-390 microg g(-1), Pb: 0.7-31.3 microg g(-1) and Zn: 18-304 microg g(-1), whereas Cd was not detected. Trace metal concentration ranges found in waters were: Co: 9.5-20.7 microg L(-1), Cr: 20.3-284 microg L(-1), Cu: 170-840 microg L(-1), Fe: 176-1830 microg L(-1), Mn: 29.3-387 microg L(-1), and Ni: 4.3-21.9 microg L(-1). Among the trace metals studied, Cd and Zn in two seasons and Pb in winter were usually not detected or in the recommended levels. In addition, Cd was not detected in the sediment during the winter season. The analysis of variance (one-way ANOVA) and correlation matrix was employed for the sediment and water samples of the two field surveys (summer and winter) comparison. The three sources showed differences in metal contents. The metal levels in sediments displayed marked seasonal and regional variations, which were attributed to anthropogenic influences and natural processes. In the Saricay Stream, high values of metals during the dry season showed an anthropological effect from small industry firms, e.g.: an olive mill and a dairy farm or water dilution during summer seasons. Finally, the pollution in this basin probably originated from small industrial, low quality coal-burned thermal power plants, and particularly agricultural and domestic waste discharges.

In this work, trace metals such as Hg, Pb, As, Cd, Cu, Fe, Mn and Zn in underground water samples obtained from three wells, an ash-pond and drinking water located near the Yatagan Thermal Power Plant were measured. As, Hg, Cu and Zn contents of the underground water were lower than those reported in the EEC (European Economic Community) and WHO (World Health Organization) guidelines. In contrast, the levels of Fe, Pb, Cd and Mn in some groundwater samples were higher than EEC and WHO guideline values. The trace metal concentrations in coal ash-pond water were observed to be lower than water quality standards with the exception of Pb. The obtained results indicated that the trace metal concentration in the sampled drinking water site did not exceed WHO limits.

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