RESEARCH ARTICLE
Geochemical, radiometric, and environmental approaches
for the assessment of the intensity and chronology of metal
contamination in the sediment cores from Oualidia lagoon (Morocco)
Nezha Mejjad
1
&
Abdelmourhit Laissaoui
2
&
Ouafa El-Hammoumi
1
&
Ahmed Fekri
1
&
Hamid Amsil
2
&
Adil El-Yahyaoui
2
&
Azzouz Benkdad
2
Received: 18 December 2017 /Accepted: 22 May 2018
#
Springer-Verlag GmbH Germany, part of Springer Nature 2018
Abstract
The present study evaluates the distribution of metals over the last 100 years in the Oualidia lagoon by examining their
concentrations in the sediment cores. The samples were analyzed by instrumental neutron activation analysis and inductively
coupled plasma mass spectrometry. Activities of
210
Pb,
226
Ra, and
137
Cs were determined by gamma-ray spectrometry for
establishing the age-depth relationships throughout the sediment cores by applying conventional models. The results indicated
that the study area is contaminated by As and Cd revealing a detectable anthropogenic input of occurring metals as a consequence
of the continuous development of human activities around the lagoon since 1950. The enrichment factor calculated for each layer
of the three cores revealed that the studied sediments present no enrichment by Pb, K, and Mn; minor enrichment by Zn, Cr, Co,
Cu, V, and Ni; and a moderately to severe enrichment by As and Cd. The pollution load index values increase from the bottom to
the top of cores, and ranged from 0.9 to 2.8, which indicates levels of pollutants ranging from background to relatively high
concentrations in the investigated sediments.
Keywords Sediment
.
Metals
.
Oualidia lagoon
.
210
Pb radiometric dating
.
CRS model
.
CF-CS model
.
Enrichment factor
.
The
pollution load index
Introduction
Coastal sediment is considered as geochemical well of pollut-
ants (metals, radionuclides…,) and, at the same time an envi-
ronmental archive of natural and human activities. Metal pol-
lution in coastal areas is one of the most environmental con-
cerns due to the serious threat facing environmental quality,
aquatic life, and human health. Numerous environmental stud-
ies have been carried out in coastal areas in the last three
decades and have shown that coastal sediments are repository
for metal pollutants and provide time-integrated records of
pollution history (Maanan et al. 2014;Oyeyiolaetal.2013;
Laissaoui et al., 2013; Uluturhan et al.,2011;Zourarahetal.
2007;Fengetal.2004).
All metal (or metalloid) species could be considered as a
Bcontaminant^ if it occurs where it is unwanted, or in a form or
content, that causes a detrimental human or environmental
effect (Mcintyre 2003). Understanding the potential ecologi-
cal risk of metals requires a systematical quantitative evalua-
tion of these contaminants (Yuan et al. 2011). Among the
environmental indices used for assessing the contamination
level in sediment are geo-accumulation index (Igeo), potential
ecological risk index (RI), the pollution load index (PLI), and
contamination and enrichment factors (EF). These indices
were usually used in order to estimate metal pollution in mine
soils (Huang et al. 2013), farming soils (Gupta et al. 2008),
lake sediments (Zahra et al. 2014), and lagoon sediments
(Maanan et al. 2014).
In the last few decades, the study of sediment cores have
shown to be an excellent tool to establish the effects of
Responsible editor: Severine Le Faucheur
* Nezha Mejjad
mejjadnezha@gmail.com
1
Laboratoire de Géologie Appliqueé, Géomatique et Environnement –
Faculté des Sciences - Ben M’sik, Casablanca, Morocco
2
Centre National de l’Energie, des Sciences et des Techniques
Nucléaires, Rabat, Morocco
Environmental Science and Pollution Research
https://doi.org/10.1007/s11356-018-2370-y
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