Supervisors info:
Σ. Πούλος, Καθηγητής Τμήματος Γεωλογίας & Γεωπεριβάλλοντος, ΕΚΠΑ
Ε. Δασενάκης, Καθηγητής Τμήματος Χημείας, ΕΚΠΑ
Β. Καψιμάλης, Δ/ντης Ερευνών του Ινστιτούτου Ωκεανογραφίας του Ελληνικού Κέντρου Θαλάσσιων Ερευνών (ΕΛΚΕΘΕ).
Summary:
The pollution of the marine environment from human activities increased during the past decades, with serious consequences to ecosystems and humans. Heavy metals are major pollutants, some of which (e.g. Ni, Fe, Cu) in small concentrations assist in the organisms’ metabolism, while others do not have any contribution (e.g. Cd, Cr, Hg, Pb, etc.). Thus, a multiparametric study is very important in order to understand the toxicity mechanisms of heavy metals in marine organism as well as the assessment of the ''health'' state of ecosystems.
This diploma thesis aims to examine the quality of surface sediments of the Saronic Gulf by using the grain size analysis as well as by determinate the concentration of principal components (ppm) and trace elements (ppm).
Based on the results of the grain size analysis, it seems that all cores consists of fine-grainned material (silt + clay) while some of them have similar sedimentation among them, as the corers EL1, EL5 & S2 or the corers UN5 & UN6. The fact that the material of all sampling cores is finned-grained contributes to the higher concentration of heavy metals in the sediment and thus the enrichment of the contaminated material.
Amoing the examined metals the relatively higher concentarions belong to Pb & Zn. In Elefsina gulf exists very intense industrial activity and minimal in the core UN5 wherein there is only very little industrial zone adjacent the sampling region. Ni also has a maximum value in the northwestern Saronic Gulf (UN5 core) due to geology (ophiolitic material - Methane volcano) and minimum in the EL1 core. Comparing the results of the enrichment factor for the main elements and for the trace elements and the ERL - ERM & TEL - PEL environmental quality criteria it is shown that the cores EL1, UN5, UN6A, UN13 & S7B correspond to an enrichment factor from zero to minimum enrichment and, therefore, zero to minimal pollution. On the other hand, the EL5 & S2 cores where moderate enrichment, indicating therefore moderate pollution. Regarding to the ERL-ERM & TEL-PEL environmental quality criteria, lead (Pb) and zinc (Zn) cause a small percentage of adverse biological effects in all sampling areas. On the other hand, arsenic (As), copper (Cu) at all sampling sites and chromium (Cr) for nuclei EL1 & S7B show moderate rates of adverse biological effects. Finally, nickel (Ni) for the entire sampling area produce a sufficient amount of pollution as well as chromium (Cr) for the surface material of the EL5 core, for the entire UN5 core, at 30-31cm for the UN13 core, for the entire UN6 core and the first 11cm of the S2 core.
Comparing the recent sampling (2017) campaign in the Saronic Gulf with the previous campaign in 1999 is concluded that there are lower concentrations in the area of Eleusis although it is an industrial zone and Psytalia (after the opeerationod the waste treatmwnt plant, while there is an increased concentration of heavy metals over the other parts of the Gulf. But, , the UN6A in the NW Saronic Gulf presents a decrease in the concentration of Cu, Cr & Zn, while in the case of UN6A an analogous decrease was observed only for Ni, Cr & Mn.
Finally, comparing the results for Saronikow to other Gulfs (Rouselaki et al,, 2007 and Kallianteris et al., 2016), except of zinc (Zn) that is appeared in higher value in the Saronic Gulf, all the other metals present much higher values in the North Evoikos Gulf (primary) and in Maliakos Gulf / R. Spercheios mouth area (secondarily) compared to the values of Saronic Gulf.
Keywords:
heavy metals, main elements, trace elements, grain size analysis
