Computational Water, Energy, and Environmental Engineering, 2013, 2, 36-40
doi:10.4236/cweee.2013.22B006 Published Online April 2013 (http://www.scirp. org/journal/cweee)
Copyright © 2013 SciRes. CWEEE
Investigation on Inorganic Pollution Level in Surface Se-
diments of Naples and Salerno Bay
Menghan Wang1, Benedetto De Vivo1, Stefano Albanese1, Annamaria Lima1,
Wanjun Lu2, Flavia Molisso3, Marco Sacchi3
1Dipartimento di Scienze della Terra Università di Napoli Federico II, Napoli, Italy
2Department of Marine Science, Faculty of Earth Resource, China University of Geosciences, Wuhan, China
3C.N.R. Istituto Geomare Sud, Napoli, Italy
Email: menghan.wang@unina.it
Received 2013
ABSTRACT
In this study, superficial marine sediments collected from 96 sampling sites were analyzed for 53 inorganic elements.
Each sample was digested in aqua regia and analyzed by ICP-MS. A developed multifractal inverse distance weighted
(IDW) interpolation method was applied for the compilation of interpolated maps for both single element and factor
scores distributions. R-mode factor analysis has been performed on 23 of 53 analyzed elements. The 3 factor model,
accounting 84.9% of data variability, were chosen. The three elemental associations obtained have been very helpful to
distinguish anthropogenic from geogenic contribution. The aim of this study is to distinguish distribution patterns of
pollutants on the sea floor of Naples and Salerno bays. In general, local lithologie s, water dynamic and anthropogenic
activities determine the distribution of the analyzed elements. To estimate pollution level in the area, Italian guidance,
Canadian sediment quality guidance and Longs criteria are chosen to set the comparability. As the result shows, arse nic
and lead may present highly adverse effect to living creatures.
Keywords: Pollution Le ve l; Compositional Data Analysis; Factor Ana l ysis; Napoli and Salerno Gulf
1. Introduction
Naples bay is a 10-mile wide gulf located in the south
western coast of Italy, while Salerno bay is a gulf of
Tyrrhenian Sea and separated from Naples bay by Sor-
rento Peninsula. Industrial complexes, intense commer-
cial and transport activities insist on this area, which
makes it potentially a heavily polluted coastal district and
in need of remediation activities. Sediments are consi-
dered as a suitable medium to distinguish contamination
and geochemical background of marine environment,
since they are the pool of different deposition source and
are a more stable medium than sea water. Moreover,
toxic contaminants prefer to adsorb on sediments surface
especially hydrophobic organics such as PAHs and PCBs.
The aim of this study is to accomplish a comprehensive
investigation of inorganic elements concentration on se-
diment surface and illustrate their distribution patterns.
2. Materials and Metho d
2.1. Sampling
Surface sediment samples (following the directives of the
national program for assessment of marine pollution of
highly contaminated Italian coastal areas) were collected
from 96 locations (Figure 1) of Naples and Salerno bays
in May 2000. A differential global positioning system
(DGPS) was used to identify each location precisely. 23
samples were collected using a box-corer with an inner
diameter of 25 cm, of which we have used the superficial
sediments to be analyzed. 63 samples were collected by
grab. Each sample was divided into three and stored in
4˚C freezer.
Figure 1. Study area and samples locations.
M. H. WANG ET AL.
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37
2.2. Chemical Analyses and Quality Control
The all air-dried sediment samples were sieved and 30 g
of the < 150 μm fraction was retained for analysis of 53
elements (Table 1). Analyses were carried out by Acme
Analytical Laboratories Ltd. (Vancouver, Canada), through
its Italian affiliate (Norwest Italia Srl, Napoli). Each
sample was digested in a modified aqua regia solution
and analyzed by inductively coupled plasmamass spec-
trometry (ICP-MS) and atomic emission spectrometry
(ICP-AES). Specifically, a 15 g split of the pulp was di-
gested in 45 ml of the aqua regia mixture (1 part concen-
trated hydrochloric acid to 1 part nitric acid to 1 part
deionised water) at 90˚C for 1 h. The solution was taken
to a final volume of 300 ml with 5% HCl. Aliquots of
sample solution were aspirated into a Jarrel Ash Atom-
comp 975 ICP-Emission Spectrometer and a Perkin El-
mer Elan 6000 ICP-Mass Spectrometer.
Table 1. Rotating component matrix.
Element
Compon ent
1 2 3
Cu .424 .78 6 .34 5
Pb .392 . 299 . 788
Zn .251 .65 5 .67 6
Ag -.005 -.141 .83 8
Ni -.006 .981 . 035
Co .167 .92 0 .06 3
U .884 -.161 .12 2
Au .105 -.048 .94 4
Th .853 .30 7 .14 7
Bi .126 .40 8 .78 1
V .609 . 541 . 163
La .89 4 -.056 .12 2
Cr .024 . 671 . 665
Ti . 722 -.309 . 015
Al .846 .48 3 . 11 6
Na .80 8 .19 6 .14 7
K .916 . 133 . 134
Sc -.033 .946 . 005
Tl .824 . 353 . 257
Hg .163 .104 .92 7
Sn .293 . 086 . 878
Be .891 .27 9 .20 7
Li .186 . 900 . 090
2.3. Statistical and Spatial Analysi s
For single element interpreting, all the data should be
transformed with proper log-ratio method to avoid nega-
tive effect of compositional property [8]. All the infor-
mation was managed in a GIS georeferenced environ-
ment, using ArcGis 9.3 software package. Geodetic ref-
erence system is the Universal Transverse Mercator (fuse
33) projection on the ellipsoid World Geodetic System
(WGS, 1984). All the geochemical maps were generated
using the Multifractal Inverse Distance Weighted (IDW)
algorithm as an interpolation method. Factor analysis
performed with the IBM SPSS Statistics 19 software
package was applied to reduce the number of dimensions
and extracting synthetic information about the distribu-
tion of elements in the studied enviro n me nt [1].
3. Results and Discussion
Heavy metals concentrations of study area were com-
pared to 3 different marine sediment quality guidelines [5]
wit h the purpose of illustrating contamination level of
Naples and Salerno bays (Table 2). Long [7] initialize s
the estimation of adverse biological effect by collect and
sum mary publications. In his work, ERL represents ef-
fect-range low which means below it rarely adverse ef-
fects, and ERM represents effect-range median which
means above it frequentl y associated with adverse effects.
Canadian sediment quality guidelines [5], shares same
idea with Long, and include results recently. In CCMEs
guideline, IQSG represents interim marine sediment
quality guideline and PEL represent probably effect level.
Italian 367 [2] set the envi ro nmen t tolerated value based
on Italian law.
Pollution levels are compared in Figure 2 by present-
ing percentage of different category samples. Concentra-
tions of Zn, Ag, Cd and Cr in sediment seldom exceed
adverse effect thres ho ld s in the area, while Ni, Hg, Pb
and Cu have median polluted value which may cause
adverse effect to living creatures as well as human beings.
Only Arsenic shows values highly dangerous, reflecting
probably mostly influence of volcanic sediments from
Neapolitan volcanoes (Vesuvius, Campi Flegri, Ischia
Island) rather than anthropogenic source.
Figure 3 s h ows the distribution pattern of selected
analyzed elements. Most of heavy toxic metals have a
similar distributio n. Ag, Hg and Pb aggregates close to
Napoli metropolitan area, indicating that intense indus-
trial, agricultural and commercial activities affect these
elements distribution pattern. Arsenic is mostly concen-
trated around Pozzuoli bay, where hydrothermal activity
related to Campi Flegrei is documented as being very
rich in As [2]. The distributions of Ni, Zn, and Cu indi-
cate the water energy decrease from coastal to deep sea
and cause finer sediment deposit off gulf. Distribution
M. H. WANG ET AL.
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38
Table 2. Heavy metals concentration comparison with different environmental guideli ne s .
Cu(ppm) Pb(ppm) Zn(ppm) Ag(ppb) Ni(ppm) Cr(p pm) Hg(ppb) As(ppm) Cd(ppm)
Average 26.4 3 9.24 6 8.56 1 03.28 2 0.29 2 6.28 97. 65 16. 85 0.1
10.00 % 7.61 20.13 35.64 31 6.98 8.92 21.7 9.68 0.05
25.00 % 14. 45 26.18 63.23 46. 5 11.8 16 42.25 12 0.07
50.00 % 26. 62 35.5 71 71 21.6 27.8 79 14.35 0.09
75.00 % 37. 81 47.47 84.43 109.5 27.7 35.75 116 .25 17.45 0.11
Med ian 29 69.7 106 5 19 7.5 38. 6 435 12. 3 0.11
MAD 12 34.4 35.8 4 50 14. 1 12. 6 356 3.05 0.03
Mini mium 3 9 16 17 2 3 3 5 0.02
Maxm ium 72 128 178 1 012 40 74 864 74 0.19
ER-L 34 46.7 150 1000 2 0.9 81 150 8.2 1.2
ER-M 270 218 410 3700 5 1.6 370 710 70 9.6
ISQG 18. 7 30. 2 124 52.3 130 7.24 0.7
PEL 108 112 271 160 700 41.6 4.2
Italian 367 30 30 50 300 12 0.3
Figure 2. Percentage of different sediment category divided by environmental guidelines. Brown bar shows the per c entage of
samples that exceed ERM, pink bar shows that between ERL and ERM while green bar shows that below ERL. Red bar
represents that exceed PEL, yellow one shows that between PEL and ISQG and blue one represents that below ISQG. Dark
grey bars shows percentage exceed Italian 367, light grey shows that below it.
Figure 3. Single elements distribution in Napoli and Salerno Gulf.
M. H. WANG ET AL.
Copyright © 2013 SciRes. CWEEE
39
pattern of Chromium indicate combination of anthropo-
genic effect and water energy effect.
To understand the distribution modes of the different
heavy metals and discriminate the different sources,
R-mode factor analysis (FA) on 23 of 53 analyzed ele-
ments was carried out. The factor model three, account-
ing 84.9% of data variability, have been chosed. The
elements are considered to describe effectively the com-
position of factors if the loading is over 0.51. The associ-
ations of the three-factor model are F1 (K, La, Be, U, Th,
Al, Tl, Na, Ti, V) accounted for 32.5% of data variability,
F2 (Ni, Sc, Co, Li, Cu, Cr, Zn, V) accounted for 27.4%
of data variability and F3 (Au, Hg, Sr, Ag, Pb, Bi, Zn, Cr)
accounted for 24.9% of data variability. Figure 4 shows
the distribution pattern of the three association factor
score s.
F1 association represents the elements whose distribu-
tion is mostly of geogenic source, meaning that human
activities have little, control on their beha vio r in Naples
and Salerno bays. F2 represents elements mainly influ-
enced by water energy. F3 is the most anthropogenic
factor, showing intense human activities of the Naples
Figure 4. Factor score association maps.
metropolitan area as the main source for this 9 elements
distribution patterns. The latter is in agreement with the
results obtained by Cicchella et al., 2005 for volcanic
soils of the metropolitan and provincial areas of Napoli.
4. Acknowledgements
Authors thank the C.N. R. Istituto Geomare Sud a Napoli
to provide samples and corresponding data, and Dr. Mo-
nica Capodanno for sediment storage and disposal. This
preliminary study is part of a more comprehensive PhD
program of M. Wang, aimed at the study as well of Per-
sistent Organic Pollutants (POP), such as PAH and PCBs,
by SERS laboratory and in situ experimental researchs to
understand the behaviour of POP with time.
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