Summary:
This thesis focuses on the geochemical analysis of urban soil samples collected from
the broader area of the Municipality of Keratsini-Drapetsona. Specifically, samples
were collected to estimate the concentrations of potentially toxic elements in the
region's soils (As, Cd, Cu, Hg, Ni, Cr, Co, Pb, Mn, Zn, Fe, and Sb). The study area was
chosen due to the extensive pollution observed, resulting from human activities
developed in recent years.
A total of 28 surface soil samples were collected, 25 of which are from the study area
(spaced 600m apart), and the remaining 3 are from the Schistos Industrial Park. The
samples from Schistos were collected to conduct supplementary research in the
broader area, as the study area was considered to be influenced by industrial activity.
The initial steps in processing the samples involved drying, disaggregation, and
sieving. Subsequently, the Aqua Regia extraction method was applied, which dissolves
metals by forming soluble chlorides. Along with these samples, duplicate, blank and
CRM samples (2711a and 2709a) were also processed using the same method. The
processed samples were then analyzed in the laboratory using an ICP-AES
(Inductively Coupled Plasma Optical Emission Spectrometer). This method of
spectroscopic analysis uses the emission spectrum of excited atoms to quantify
concentrations of chemical elements in solutions.
The main conclusions from the sampling and laboratory analysis, which was conducted
without significant errors, highlight the substantial extent to which human activity has
contributed to the pollution of urban soil in the broader area with toxic elements. The
interventions are mainly point-based, with a result of large deviations observed in the
concentration values per element and per position.
In particular, very high concentrations of potentially toxic elements were observed near
the Port of Piraeus, the "HERACLES" cement industry, and the Fertilizer Complex.
Concentrations are lower on main roads and side streets. In areas with educational
facilities (University of Piraeus, schools), significant concentrations of Mn (686 mg/kg),
Ni (931 mg/kg), Cr (1406 mg/kg), Co (15.3 mg/kg), and Fe (21111 mg/kg) were detected. Samples from roadsides showed high levels of Cr (1406 mg/kg), Fe (21111
mg/kg), Mn (686 mg/kg), and Sb (9.03 mg/kg). A sample from the main avenue,
Grigoriou Lambraki, recorded the highest Hg concentration (0.55 mg/kg). Samples
collected from gardens indicate that soils are less affected by toxic elements, with As
(35 mg/kg) and Co (15.3 mg/kg) being the most prominent concentrations.
Finally, the factor analysis determines the origin of the elements with load values
greater than 0.6 and less than -0.6. The first factor represents elements of
anthropogenic origin (Cd, Cu, Cr, Pb, Zn, Sb), while the second includes geogenic
elements (As, Ni, Cr, Co, Mn, Fe). Cr has a dual origin (both anthropogenic and
geogenic), while Hg was excluded from the analysis. Cluster analysis followed, forming
two groups of samples: one consisting of samples from areas with low human activity,
and the other from areas with heavy traffic and human intervention.
