Spatial distribution and contamination assessment of heavy metals in surface sediments of Lake Burullus, Egypt

The potentially bio-available heavy metals were assessed in the bulk and the three fine fraction sediments (Ø 3 , Ø 4 , and Ø 5 ) from 24 stations across Lake Burullus. We found the same pattern of metal contents in all fractions with the sequence: Fe > Mn > Zn > Cu ≥ Ni > Pb > Cd. The recorded concentrations of Cu, Zn, Ni, Mn, and Fe in Burullus were higher than the coastal area outside the lagoon. Some metals showed trend of different spatial distribution inside the lake; the highest Cu (40.7–82.2 μg/g) and Mn (495.6–690.7 μg/g) was recorded in the middle sector and Fe (1912.6–2017.4 μg/g) recorded in the western sector of the lake. The concentrations of Cu in Ø 4 (41.4–82.2 μg/g) and Ø 5 (28.2–76.2 μg/g) were relatively higher than in the total sediments (5.8–44.8 μg/g); meanwhile, Fe and Mn in fine fractions reached 1.2–1.5 times higher than bulk sediments. Correlation coefficient and principal component analysis (PCA) showed strong association between Cu, Zn, and Ni. On the other hand, there was partial association of Mn with Fe indicating anthropogenic sources from the industrial and agriculture drains. The calculated environmental and biological indices pointed out that the leachable metals in Lake Burullus were classified between unpolluted and moderately polluted. The potential biological adverse effects were in minimum susceptibility because the levels of metals were predominantly below the sediments severe effect levels (SEL) quality guidelines.