Hazardous and harmful substances in sediments of the Jegricka stream

Abstract

The Jegricka had been a natural stream which was partially regulated and included into the canal network Danube-Tisza-Danube Hydro System (Vojvodina, Serbia). The stream has a multifunctional character. It provides irrigation water and serves for land reclamation activities in the area through which it flows. The area includes farmland for the most part and several small villages. The stream itself and a zone along its banks have been recognized for special ecological significance and they were awarded the status of a protected natural resource. Sediments from the Jegricka stream have been analyzed in order to assess possible impact of various degradation processes on the environmental status of this protected natural resort. Concentrations of hazardous and harmful substances were determined in 20 sediment samples gathered at different points of the stream. The analyses involved eight trace elements (heavy metals and microelements) and sixteen PAH compounds. The obtained results indicated that the quality of sediments was mostly satisfactory, in spite of a relatively large exposure to point and non-point pollution sources (wastewaters from municipal and industrial sources, agriculture etc.). The contents of heavy metals in the sediments were found to be within the limits of tolerance (Pb 3.28-27.40; Cd 0.00-0.20; Cr 7.27-38.97; Ni 5.11-35.66; Cu 5.91-33.74; Zn 13.80-92.12; Co 1.60-11.94 mg kg-1). Also, the concentration of total PAHs was below the level considered as harmful to the environment. The concentrations of individual PAHs in the sediments were as a rule below 1 mg kg-1. The only exceptions were increased arsenic concentrations. Maximum arsenic concentrations determined for some locations, for example 79.37 and 69.73 mg kg-1, exceed several-folds the maximum permissible concentration. These excessive concentrations may have a negative impact on the environment in the stream itself and its surroundings.