Kemija u Industriji (Nov 2007)
Influence of the Leather Industry on the Pollution of Coastal Sediments by Chromium in the Zadar Area
Abstract
The influence of the long term discharge of untreated wastewaters from the leather factory in Zadar on the distribution of chromium in the bay of Brodanov Jaz has been investigated in this study. The investigation was performed at four locations along the bay (at the mouth - P1, the beginning - P2, the middle - P3 and the end - P4 of the bay). A sediment sample was also taken at an unpolluted location near the town of Nin, 20 km to the north of the Brodanov Jaz bay, for the purpose of comparison. The chromium concentration was determined in 3 granulometric competition of the sediment (A: 0.063-2.00 mm, B: 0.010-0,063 mm, C:<0.010 mm). The highest concentracion of chromium was observed in the sediment taken nearest to the wastewater outlet. The concentration of Cr in the sediment at the mouth (P1) was considerably higher (6 times) than at the end of the bay (P4). At the mouth (P1) and at the beginning of the bay (P2) Cr concentration was about 25 times higher than at the reference location in Nin. Concentrations of Cr in all samples were inversely proportional to grain size, so the finest fractions of sediment (C and B) contained about 4 times higher Cr concentrations than in the large grain fraction (A) of the same samples. The obtained distribution of Cr in the bay of Brodanov Jaz indicates that the increased Cr concentrations in sediment came from the leather industry, and that they are of anthropogenic origin.
