Spatial and temporal variability of composition of urban effluents in the island of Lesvos, Greece

The spatial and temporal variability in the composition of effluents of the coastal town of Mytilene, island of Lesvos, Greece, was investigated in 8 sewers of the town. Differences were found in the quality of effluents betw een the old and new parts of the town and were attributed mainly to the dif ferent design and construction of the sewers, as well as to the occasional discharge of septage into the sewerage network in parts of the town. During summer the population and water consumption increase, leading to partial d ilution of the organic load. However, in the same period (July), the concen trations of dissolved Zn and particulate Pb were enriched. The reasons for such an increase are not clear. At present the seasonal metal peaks (Pb and Zn) are attributed to the increased traffic (Pb and Zn) and to increased c orrosion under the prevailing weather conditions of the water supply networ k, which includes a very large number of galvanized storage tanks (Zn). (C) 2000 Elsevier Science Ltd. All rights reserved.