The effects of land-based activities on the near-shore environment of the Red Sea, Egypt

摘要

The heavy metal contents of Cu, Zn, Pb, Mn and Cd were measured using AAS in the fine sediment fractions (empty set(3), empty set(4) and empty set(5)) and the seawater at six sites represent the main land-based activities at Hurghada, Safaga and Hamrawin along the Red Sea coast. The fine sediment group (empty set(3) + empty set(4) + empty set(5)) was varied between 24.61 and 88.88 % from the total sediment percentage, whereas empty set(3) was the most abundant fraction with average percentages between 14.92 % at site III and 28.3 % at Site IV followed by empty set(4) with average between 8.04 % at site III and 57.46 % at site II; therefore empty set(3) and empty set(4) were considered the essential pollutant bearing fractions. Cu recorded the highest average content (248.69 mu g/g) at site I, Zn (746.24 mu g/g) at site V, Pb (215.86 mu g/g) at site III, Mn (407.66 mu g/g) at site IV and Cd recorded the highest average (28.47 mu g/g) at site VI. Site II showed the lowest average contents of the different metals that may attribute to the continuous leaching of the metal bearing fractions by the longshore currents and waves. In the seawater, site IV recorded the highest Cu average (10.49 mu g/l), site III showed the highest averages of Zn and Pb (63.02 and 42.49 mu g/l) whilst site VI recorded the highest averages of Mn and Cd (17.78 and 1.13 mu g/l, respectively). Zn, Pb, Mn and Cd showed significant correlation relationships to each other in sediments at Hurghada indicated that they tend to accumulate in the same form. The insignificant correlations of Cu and other metals at Safaga and Hamrawin indicated the accumulation in multiple forms under variable local conditions. The different sites were classified between slightly and highly polluted with heavy metals. The obtained results illustrated that the land-based activities at the different localities have serious threatening on the near-shore environment and Safaga marine area was more polluted than Hurghada and Hamrawin.