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Cadmium concentration and organic matter content were determined in sediments and suspended matter samples, which were sampled every month during the period of one year (April 2000 - April 2001) at four stations in the Kaštela Bay. One sediment core was sampled at every station. Furthermore, a granulometric composition of the sediment samples was determined. The estimated sediment accumulation rate was 32.18 g m-2 day-1. Sedimentation was more intensive in the eastern part of the Bay. Cadmium concentration in the suspended matter and the sediment were in the range of 0.131-1.057 mg kg-1 and 0.082-0.904 mg kg-1, respectively. The difference of the concentration most probably is related to the difference of the grain size of the suspended matter and the sediments. The vertical distribution reveals the decrease of cadmium concentration with the sediment depth, which indicates the anthropogenic origin of cadmium. The anthropogenic origin of cadmium is also indicated by its spatial distribution in the sediments and suspended matter. The highest concentration was determined at the station located in the northeastern part of the Bay nearby industrial wastewater discharges. Seasonal changes of the concentrations at all the stations were recorded, showing the higher values during the winter season, as the result of an increased resuspension of the sediment, as well as increased inputs from the land and the atmosphere. However, the higher values in suspended matter are associated with the lower values in the sediments, which leads to the conclusion that the sediment resuspension plays the important role in cadmium distribution between the sediments and the suspended matter. The linear correlation, which was established between cadmium concentration in the suspended matter and the sediment accumulation rate, indicates terigenous origin of cadmium. |
