Assessment of trace metals contamination in the coastal sediments of the Egyptian Mediterranean coast

Trace metals contamination has been recently increased in the Egyptian Mediterranean  coast owing to
the nearby anthropological activities. This investigation aimed to detect the concentrations of six
different trace metals (Fe, Mn, Cu, Cd, Pb and Zn) in surface sediments from the central part of the
Egyptian Mediterranean coast, and to assess their state of contamination from different indices and risk
factor calculations. Mean concentrations of Cu, Pb and Zn were lower and the mean concentration of Cd
was higher compared to the background values. The assessment of pollution was mainly based on the
contamination indices. Based on the contamination factor, Pb was the most enriched element followed
by Cd, Mn, Zn and Cu. Most of the sites show low contamination with respect to Pb, Mn, Cd, Fe, Zn and Cu.
The pollution load index also suggests that all the coastal sediments are unpolluted. According to the
geoaccumulation index, the sediments were classified into unpolluted with Mn, Cd, Fe and Pb, and
unpolluted to moderately polluted with Pb. Risk evaluation revealed that Cd had the greatest ecological
risk, followed by Pb, Cu, Mn, while Zn had the lowest risk. With the aid of statistical methods, the origin
of metals is classified into two clusters (A and B). Group A consists of Fe, Mn and Cu, whereas group B
contains Zn, Pb and Cd. In the first cluster Fe and Mn are joined to each other at a positive and significant
similarity (0.68). Fe is recognized as an indicator of lithogenous origin, therefore, its higher similarity
with Mn may be indicative of the similar origin for Manganese. In the second cluster Pb and Zn are joined
to each other at a positive and significant similarity (0.80). Pb is recognized as an indicator of anthropogenic
origin, therefore, its higher similarity with Zn may be indicative of the similar origin for Zinc