Urban geochemical mapping in the Campania region (Italy)

Urban geochemical mapping in the Campania region (Italy)

D. Cicchella1, B. De Vivo2, A. Lima2, S. Albanese2 & L. Fedele2

1Dipartimento di Studi Geologici ed Ambientali, Università degli Studi del Sannio, Via dei Mulini 59/A, 82100Benevento, Italy (e-mail: [email protected])

2Dipartimento di Scienze della Terra, Università di Napoli ‘Federico II’, Via Mezzocannone 8, 80138 Napoli, Italy

ABSTRACT: This work reviews the results of research conducted in the last fiveyears on urban soils of the Campania region, southern Italy. Approximately 2000topsoil samples were collected and analysed for 40 elements, among which areincluded the potentially harmful elements (PHE). The two most relevant objectivesachieved were the determination of background levels for each element, usingconcentration–area (C–A) and separation–anomaly (S-A) algorithms, and the pro-duction of an extensive cartography, published in a series of geochemical atlases. Thelatter show that high PHE concentrations, exceeding many times the local naturalbackgrounds (especially Pb, Hg, Sb, Zn), are found in the most densely populatedareas, often affected by heavy vehicular traffic and industrial activities. Many soilsamples exceed the limits set for PHE by the Italian Ministry of the Environment inlaw DM 471/99 for residential land use. The geochemical maps can prove to be veryuseful both for scientists and professionals working towards the restoration ofcontaminated areas, as well as serving to refine the Italian environmental legislationto be more effective in local situations.

KEYWORDS: geochemical mapping, urban soil, background concentration, environmental pollution

INTRODUCTION

In this paper we review the results of a geochemical surveycarried out by our research group in the last five years in fiveurban areas (Avellino, Benevento, Caserta, Napoli, Salerno) ofthe Campania Region (Italy) (Fig. 1), wherein concentrationsand distributions of major, minor and trace elements in soilswere determined.

In particular, we determined the concentrations of all theelements considered as ‘pollutants’ by Italian legislation (lawDM 471/99; Ministero dell’Ambiente 1999), monitoring animportant aspect related to the health of the environment.Italian legislation set trigger and action levels, in additionto organic substances and compounds, for only a restrictednumber of inorganic elements. However, a geochemical surveycannot ignore other elements, even if national legislation doesnot consider them to be harmful. Hence, we analysed for amuch wider set of inorganic elements in order to properly assessand monitor the quality of the environment.

In carrying out this survey, mapping of contaminant distri-bution was used to allow immediate appraisal of the variabilityof potentially harmful elements (PHE) and to enable rapididentification of areas that may contain hazardous concen-trations. This methodology is essential for site and subsequentrisk assessment.

The investigation included the determination, for each ele-ment, of both the distribution of concentration values withinthe survey area and the definition of background values forenvironmental purposes. The results of this geochemical surveyhave been presented in five environmental geochemical atlasesedited by the research group led by Professor De Vivo(Albanese et al. 2007b; Cicchella et al. 2007; De Vivo et al. 2006a;Fedele et al. 2007; Frattini et al. 2006a; Lima et al. 2007). The

atlases include maps (dot maps, interpolated data distribution,baseline values distribution, anomaly values distribution, inter-vention maps, factor scores association maps, radioactivitymaps), a detailed description of methodologies and a detailedinterpretation of the element distribution patterns. The surveyswere detailed follow-ups of the geochemical survey carried outin 2001 on the stream sediments of the entire Campania region(De Vivo et al. 2006b, c; Albanese et al. 2007a).

The research activity carried out in the last five years in theCampania region (Italy) is summarized in Table 1; analyticaldata and maps will soon be made available on the Internet.Examples of the published maps – the baseline and anomalyvalues of Zn in the soils of provincial areas of Napoli, and theinterpolated data distribution of Pb in the Avellino urban area– are shown in Figures 2 and 3, respectively.

METHODS

Soil samples were collected in the municipal areas of Avellino(123 samples), Benevento (156), Caserta (211), Salerno (151)and the provincial area of Napoli (982) (Fig. 1). Since thebulk of the PHE released in the environment is derived fromvehicle traffic and industrial activity (Li et al. 2001; Mantaet al. 2002; Tarzia et al. 2002; Fordyce et al. 2005; Wong et al.2006), we sampled city centres and industrial areas with agreater density than suburban areas, which are typically lessaffected by heavy metal pollution. Sampling locations includedgardens, parks, open spaces, cross-roads, road verges and wasteground.

Each sample is a composite of five subsamples collectedfrom the corners and the centre of a 10 m3 site, in accordancewith internationally adopted methods (Salminen et al. 1998;

Geochemistry: Exploration, Environment, Analysis, Vol. 8 2008, pp. 19–29 1467-7873/08/$15.00 � 2008 AAG/ Geological Society of London

2005). Approximately 3 kg of soil were collected from between0 and 15 cm below the surface, and stored in inert plastic bags.

All samples were air-dried to prevent the volatilization of Hgand sieved to collect 30 g of the <100-mesh fraction (150 µm)for chemical analysis. Analyses were carried out at AcmeAnalytical Laboratories Ltd (Vancouver, Canada), accreditedunder ISO 9002, by ICP-MS and ICP-AES using Acme’sGroup 1F-MS package (modified aqua regia digestion) for Ag,Al, As, Au, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K, La, Mg,Mn, Mo, Na, Ni, Os, P, Pb, Pd, Pt, S, Sb, Sc, Se, Sr, Te, Th, Ti,Tl, U, V, W, Zn. The detection limits and statistical parametersare listed in Tables 2, 3 and 4. For statistical computation, thedata below the instrumental detection limit (IDL) have beenassigned a value corresponding to 50% of the detection limit.

Samples were digested prior to analysis using modified aquaregia (two parts concentrated HCl to two parts HNO3 to twoparts distilled water, kept at 95�C for 1 h). The quality of all datawas assessed by estimations of accuracy and precision (Cicchellaet al. 2008a). Calibration solutions were included at the begin-ning and end of each analytical run (40 solutions). Spiking of the

digestion solution with a tracer element controls internalstandardization. Precision is �100% at the detection limit andimproves to better than �10% at concentrations of 50 timesthe detection limit or higher. Precision was calculated onin-house replicates and blind duplicates submitted by theauthors. Accuracy was calculated on Acme’s in-house referencematerial (standards DS3, DS4, DS5, DS6). Reference materialswere calibrated to an aqua regia digestion/ICP-MS determi-nation against published values for a concentrated HCl andHNO3 digestion of Canadian Certified Reference materials(CCRMP) TILL4 and LKSD2. The results obtained for thesereference materials were consistent with the values obtainedfrom the certification programme (e.g. Cu, Pb, Zn, Mo, Ag).

A further 370 soil samples (34 for Avellino, 40 forBenevento, 40 for Caserta, 200 for Napoli and 49 for Salerno)were also analysed for Pt, Pd and Rh; the results are given inCicchella et al. (2003, 2008b).

At most soil sampling sites (Fig. 1), gamma-ray spectrometrydata were also collected, using a hand-held Scintrex GRS-500spectrometer (differential gamma-ray). The energy windows

Fig. 1. Sample location maps of investigated urban areas in Campania region (Italy).

D. Cicchella et al.20

were selected between 1.35 and 1.59, 1.65 and 1.87, and 2.45and 2.79 MeV to measure total gamma-ray activity from natu-rally occurring K, U and Th series, respectively. In addition,total count >0.08 MeV (TC1) and >0.40 MeV (TC2) weredetermined. A barium-133 standard was used to calibrate thespectrometer. The instrument was calibrated at intervals of twoto three hours. Each gamma reading was averaged over aninterval of 50 seconds. The results of the gamma ray surveyare discussed in Lima et al. (2005). A total of 107 soil sampleswere analysed using EDTA digestion method with the aim ofevaluating bioavailability of the PHE; the results are discussedin Albanese (2008).

RESULTS

The geochemical database, the cartography and all the collecteddata proved to be instrumental in defining reference ‘back-ground values’ for metallic elements. The differentiation be-tween background from baseline values is very important in thecontext of the Italian environmental law (DM 471/99), whichsets trigger and action levels for selected toxic elements, but at

the same time states that such limits can be raised when it isproved that the specific study area is characterized by back-ground values higher than the intervention limits themselves.

Background values of PHE for the urban areas of Avellino,Benevento, Caserta and Salerno and the provincial area ofNapoli are shown in Table 5. These values were obtained usingthe GeoDas program (Cheng 2003) by means of applicationof the and methods separation–anomaly (S–A) andconcentration–area (C–A) methods. Detailed descriptions ofthis methodologies can be found in Cheng (1999a, b), Cheng etal. (1994, 1996, 2000, 2001); Lima et al. (2003b, 2008); Cicchellaet al. (2005).

Elemental distribution in the soils of Napoli, provincialand urban area

A strong element contamination (Pb, Zn, Cu, Sb, Ag, Au, Hg),concentrated in the eastern part of the city and possibly due toboth motor vehicles and industrial plants, was identified in themetropolitan and provincial areas of Napoli (including theresidential areas).

Table 1. Summary of geochemical baseline mapping activity in the Campania region (Italy).

Survey area N Samplemedium

Elements and other parameters Timeperiod

Related publications

Campania Region(13 600 km2)

2389 Stream sediments Ag, Al, As, Au, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K,La, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sc, Se, Sr, Te, Th, Ti,Tl, U, V, W, Zn, pH, conductivity, partial and totalradioactivity

1999–2001 Lima et al. (2003b, 2005);De Vivo et al. (2006b);Albanese et al. (2007a)

Volturno river basin(5455 km2)


1999–2002 De Vivo et al. (2001,2006c)

Sele river basin(3200 km2)


1999–2002 –

Somma-Vesuvius(200 km2)

188188

TopsoilsSubsoils

Ag, Al, As, Au, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K,La, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sc, Se, Sr, Te, Th, Ti,Tl, U, V, W, Zn, pH, partial and total radioactivity

1998 Costabile et al. 2004

Napoli municipal area(120 km2)

207 Topsoils Ag, Al, As, Au, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K,La, Mg, Mn, Mo, Na, Ni, Os, P, Pb, S, Sb, Sc, Se, Sr, Te, Th,Ti, Tl, U, V, W, Zn, Platinum Group Elements, partial andtotal radioactivity, Pb isotopes

2001 Cicchella et al. (2003);De Vivo et al. (2006b);Cicchella et al. (2008a, b)

Napoli provincial area(1171 km2)

982 Topsoils Ag, Al, As, Au, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K,La, Mg, Mn, Mo, Na, Ni, Os, P, Pb, S, Sb, Sc, Se, Sr, Te, Th,Ti, Tl, U, V, W, Zn, partial and total radioactivity

2001 De Vivo et al. (2006a),Cicchella et al. (2005,2008a)

Ischia island (47 km2) 19816

TopsoilsSubsoils

Ag, Al, As, Au, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K,La, Mg, Mn, Mo, Na, Ni, Os, P, Pb, S, Sb, Sc, Se, Sr, Te, Th,Ti, Tl, U, V, W, Zn partial and total radioactivity

20032004

Frattini et al. (2006a)Frattini et al. (2006b)

73 Groundwater 72 elements, pH, conductivity 2000–2002 Lima et al. (2003a)Avellino municipalarea (30 km2)

123 Topsoils Ag, Al, As, Au, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K,La, Mg, Mn, Mo, Na, Ni, Os, P, Pb, S, Sb, Sc, Se, Sr, Te, Th,Ti, Tl, U, V, W, Zn Platinum Group Elements, partial andtotal radioactivity

2004 Albanese et al. (2007b)

Benevento municipalarea (130 km2)

156 Topsoils Ag, Al, As, Au, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K,La, Mg, Mn, Mo, Na, Ni, Os, P, Pb, S, Sb, Sc, Se, Sr, Te, Th,Ti, Tl, U, V, W, Zn, Platinum Group Elements, partial andtotal radioactivity

2004 Cicchella et al. (2007)

Caserta municipal area(56 km2)

211 Topsoils Ag, Al, As, Au, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K,La, Mg, Mn, Mo, Na, Ni, Os, P, Pb, S, Sb, Sc, Se, Sr, Te, Th,Ti, Tl, U, V, W, Zn, Platinum Group Elements, partial andtotal radioactivity

2004 Lima et al. (2007)

Salerno municipal area(59 km2)

151 Topsoils Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga,Hg, K, La, Mg, Mn, Mo, Na, Ni, Os, P, Pb, S, Sb, Sc, Se, Sn,Sr, Te, Th, Ti, Tl, U, V, W, Zn, Platinum Group Elements,partial and total radioactivity

2005 Fedele et al. (2007)

Campania Regionurban areas

107 Topsoils EDTA digestion and analysis for potentially harmful elements 2005 Albanese (2008)

N, number of samples.

Urban geochemical mapping 21

Fig. 2. Zinc baseline and anomaly values maps of soils of the provincial area of Napoli.


Fig. 3. Lead dot and interpolated data distribution maps of the municipal area of Avellino.


The enrichment factor for Pb and Zn is from three to fourtimes higher than background values, inferred from uncontami-nated soils of volcanic areas (De Vivo et al. 2006a; Cicchellaet al. 2005). Platinum and Pd concentrations in the most

urbanized areas of the city were also very high, due to therelease of abraded fragments from vehicle catalytic converters.In fact Pt and Pd concentrations in soils show a very similarspatial distribution to that of Pb (Cicchella et al. 2003). Theconcentration levels of many of the investigated elementsexceed the intervention limit set by the Italian environmentallaw DM 471/99 (Fig. 4). The levels of these pollutants are notof concern in the suburban areas, but in some places, particu-larly areas with higher traffic intensity (e.g. historic city centre)and in the eastern industrialized area of Napoli, concentrationsare above the maximum acceptable limits for residential/recreational land use and in some instances even forindustrial/commercial land use (Fig. 4). Smaller risk areas canalso be found close to the Mt. Somma-Vesuvius, in the vicinityof flourishing vineyards where the concentrations of Cu and Pare very high.

Lead isotope investigation demonstrates that road traffic isthe main source of metal pollution of Neapolitan soils(Cicchella et al. 2008a). The provincial suburban areas showelemental concentration patterns where geogenic control ismore evident, with PHE concentration reflecting natural back-ground values.

Elemental distribution in the soils of Avellino urban area

Soils of the municipal area of Avellino are of volcaniclasticorigin. The highest concentrations of PHE are found both inthe densely populated city centre and in the industrial district inthe northeastern sector of the city. Here, Pb values rangebetween 112 and 219 mg/kg, while Zn ranges between 141 and413 mg/kg. The remaining part of the territory has a very lowpopulation density, with a morphology characterized by thepresence of hills and a few country trails. Here, samples werecollected from agricultural soils not intensely reworked, wherefruit trees rather then vegetables are grown. Soils of these areaspresent the highest values of geogenic elements such as U, Th,K and Cu, the latter ranging between 270 and 1099 mg/kg andmainly related to the presence of vineyards (Albanese et al.2007b). Soils of the entire urban territory are characterized byelevated As baseline values with a mean value of 20.9 mg/kg(Table 3), slightly above the safeguard value set by DM 471/99(20 mg/kg) (Fig. 4). These values represent natural backgroundsince they are consistent with the enrichment values in the localvolcanic rocks (Albanese et al. 2007b). The Se content (between0.30 and 1.20 mg/kg) is considered normal, contrary to Tlconcentrations, which exceed the safeguard limits (1 mg/kg) inthe whole municipal area.

Elemental distribution in the soils of Benevento urbanarea

Geochemical maps describing metal distribution in soils of themunicipal area of Benevento indicate a positive correlationbetween the majority of the elements (Cu, Cd, Hg, Pd, Pb, Pt,Sb and Zn) and the most densely populated areas, the streetnetwork, high traffic flows and the industrial areas. The highestconcentrations are found near emission sources (i.e. streets),where the local morphology and climate, with little ventilation,force pollutants to stagnate.

Variations in the concentrations of certain heavy metals (Pb,Sb, Zn) help to evaluate the degree of anthropogenic contami-nation; in particular, the positive correlation among theseelements supports the identification of high traffic flow as beingthe main source of pollutants.

Concentrations found in residual soils, sampled mainly in thesuburban areas of Benevento, fall mostly within local back-

Table 2. Statistical parameters for major elements in the topsoils of urban areas inCampania region and the provincial area of Napoli.

Min. Max. Mean Median Std dev.

Al (%) (d.l.=0.01%)Avellino 2.97 8.61 6.57 6.48 1.19Benevento 0.48 6 2.8 2.67 1.11Caserta 0.76 7.72 4.72 4.92 1.19Napoli 0.64 8.69 3.92 3.91 1.55Salerno 0.66 7.39 3.23 2.99 1.62

Ca (%) (d.l.=0.01%)Avellino 0.72 10.8 2.17 1.73 1.57Benevento 0.53 19.5 4.72 3.91 3.64Caserta 0.27 12.87 2.65 1.7 2.53Napoli 0.17 16.57 2.49 2.03 2.26Salerno 0.5 20.68 6.72 6.08 4.35

Fe (%) (d.l.=0.01%)Avellino 2.12 4.24 3.29 3.26 0.39Benevento 1.01 3.4 2.11 2.11 0.45Caserta 1.25 3.85 2.79 2.84 0.47Napoli 0.52 15.46 2.37 2.18 1.02Salerno 0.71 4.25 2.25 2.32 0.69

K (%) (d.l.=0.01%)Avellino 0.7 2.8 1.62 1.61 0.48Benevento 0.08 3.24 0.63 0.6 0.29Caserta 0.14 2.72 0.59 0.56 0.22Napoli 0.21 6.82 2.13 1.43 1.57Salerno 0.11 2.06 0.56 0.49 0.31

Mg (%) (d.l.=0.01%)Avellino 0.41 3 0.76 0.71 0.28Benevento 0.2 0.94 0.45 0.44 0.11Caserta 0.15 1.79 0.4 0.37 0.16Napoli 0.1 2.3 0.58 0.5 0.31Salerno 0.26 7.49 2.30 1.9 1.48

Na (%) (d.l.=0.001%)Avellino 0.09 0.53 0.29 0.29 0.08Benevento 0.005 1.08 0.08 0.07 0.09Caserta 0.01 1.29 0.1 0.09 0.11Napoli 0.03 2.95 0.61 0.53 0.39Salerno 0.01 0.84 0.12 0.08 0.12

P (%) (d.l.=0.001%)Avellino 0.09 0.38 0.2 0.2 0.06Benevento 0.04 0.35 0.1 0.08 0.05Caserta 0.03 1.18 0.15 0.1 0.16Napoli 0.005 0.84 0.19 0.16 0.13Salerno 0.02 0.87 0.12 0.1 0.09

S (%) (d.l.=0.01%)Avellino <0.01 0.31 0.06 0.05 0.05Benevento <0.01 0.13 0.02 0.02 0.02Caserta <0.01 0.18 0.04 0.03 0.03Napoli <0.01 0.66 0.05 0.04 0.07Salerno 0.01 0.18 0.05 0.05 0.03

Ti (%) (d.l.=0.001%)Avellino 0.06 0.21 0.15 0.15 0.03Benevento 0.004 0.23 0.06 0.05 0.04Caserta 0.005 0.27 0.16 0.17 0.05Napoli 0.024 0.28 0.13 0.13 0.05Salerno 0.01 0.29 0.1 0.1 0.06

d.l., Detection limit


ground values. On the other hand, non-residual soils sampled inflowerbeds of the city centre, show much higher concentrationscompared to those of suburban areas (Cicchella et al. 2007).

Lead concentrations measured in these areas (up to390 mg/kg) are at least ten times greater than the naturalbackground (c. 30 mg/kg) and should definitely cause concern;in particular, 12 samples exceed the Pb trigger and action levelset by the DM 471/99 for residential areas (100 mg/kg) (Fig. 4).Similarly, Cu (up to 495 mg/kg), Zn (up to 478 mg/kg) and Cdlevels (from 1.9 to 2.4 mg/kg, ten times greater than the localbackground of 0.1–0.2 mg/kg) are also extremely high, exceed-ing in some locations the legal limits (Fig. 4).

Soils in the whole northern area of Benevento show highCo concentrations, for the most part above the 20 mg/kglimit set by DM 471/99 for residential areas. Such concen-trations can be simply linked to the natural Co content oflocal lithotypes, including clays and marls, but anthropogenicpollution cannot be completely ruled out as a possible sourcefor those samples with higher Co content (three samples with29 mg/kg). Nickel concentrations are mostly due to locallithology and its distribution is very similar to that of Co, assuggested by their high correlation index (0.84). Arseniccontents are always below the safeguard value set by the law(20 mg/kg), but its concentration in soils is sometimes twicethe natural background (c. 8 mg/kg). Mercury background inBenevento soils is generally below 0.04 mg/kg, but in someareas concentrations up to 25 times this value were found(Cicchella et al. 2007).

Table 3. Statistical parameters for potentially harmful elements in the topsoils of urbanareas of Campania region and the provincial area of Napoli.

Min. Max. Mean Median Sdt dev.

As (mg/kg) (d.l.=0.1 mg/kg)Avellino 8.6 36.5 20.9 20.3 4.7Benevento 3.2 17.1 8.3 8.2 2.6Caserta 3.7 41.7 15.8 15.9 3.9Napoli 1 163.8 12.4 11.6 9.2Salerno 3.1 30.1 10.5 10.4 4.5

Be (mg/kg) (d.l.=0.01 mg/kg)Avellino – – – – –Benevento – – – – –Caserta – – – – –Napoli – – – – –Salerno 0.5 11.8 4.1 3.8 2.3

Cd (mg/kg) (d.l.=0.01 mg/kg)Avellino 0.19 1 0.4 0.4 0.1Benevento 0.01 2.4 0.3 0.2 0.3Caserta 0.09 2.9 0.7 0.5 0.5Napoli <0.01 10.6 0.5 0.3 0.7Salerno 0.09 2.3 0.5 0.4 0.3

Co (mg/kg) (d.l.=0.1 mg/kg)Avellino 8.3 19.7 13.5 13.5 2.5Benevento 5.1 33.3 12.2 10.6 5.6Caserta 3 15.7 9.4 9.3 2.1Napoli 0.5 36.6 9.3 7.2 5.7Salerno 2.3 22.8 8 8 2.9

Cr (mg/kg) (d.l.=0.5 mg/kg)Avellino 9.4 155.3 16 14 13.4Benevento 9.9 54.3 19.5 18 6.2Caserta 2.1 37.6 14.7 12.5 7.2Napoli <0.5 578.7 12.5 8.3 26.9Salerno 4.8 115.2 19.4 17.2 10.8

Cu (mg/kg) (d.l.=0.01 mg/kg)Avellino 49 1131 152 112 130Benevento 8 506 46 36 45Caserta 5 275 36 31 25Napoli 4 3965 163 97 262Salerno 6 710 75 61 73

Hg (µg/kg) (d.l.=0.005 µg/kg)Avellino 27 922 115 80 107Benevento 11 1085 59 23 139Caserta 3.8 1262 84 62 112Napoli 5 2656 191 91 267Salerno 2.5 846 87 56 100

Ni (mg/kg) (d.l.=0.1 mg/kg)Avellino 9.4 33.8 15.2 15 3Benevento 8.7 55.6 22.0 18.4 10.1Caserta 2.6 43 12.8 11.6 5.7Napoli 0.8 689 11.8 9.9 23Salerno 3.8 73.6 16.6 15.3 7.3

Pb (mg/kg) (d.l.=0.01 mg/kg)Avellino 47 230 87 77 30.2Benevento 5.4 392 44 33 51.7Caserta 6.2 288 68 57 39.4Napoli 6 2052 100 61 140Salerno 8.3 1306 126 67 172

Sb (mg/kg) (d.l.=0.02 mg/kg)Avellino 0.28 4.79 0.85 0.64 0.67Benevento 0.17 6.96 0.65 0.35 0.92Caserta 0.26 5.14 0.83 0.61 0.68Napoli 0.21 42.8 1.44 0.73 2.67Salerno 0.25 19.57 2.13 1.22 2.84

Table 3. continued

Min. Max. Mean Median Sdt dev.

Se (mg/kg) (d.l.=0.001 mg/kg)Avellino 0.30 1.20 0.65 0.60 0.18Benevento 0.05 0.7 0.31 0.30 0.11Caserta 0.075 1 0.35 0.3 0.19Napoli 0.05 1.9 0.33 0.30 0.22Salerno 0.2 1.3 0.47 0.4 0.18

Sn (mg/kg) (d.l.=0.02 mg/kg)Avellino – – – – –Benevento – – – – –Caserta – – – – –Napoli – – – – –Salerno 0.5 125.6 6.44 4.6 10.88

Tl (mg/kg) (d.l.=0.001 mg/kg)Avellino 0.91 2.75 1.91 1.93 0.29Benevento 0.05 2.2 0.79 0.77 0.38Caserta 0.15 2.71 1.55 1.58 0.42Napoli 0.18 69 1.51 1.14 2.57Salerno 0.13 1.79 0.88 0.9 0.42

V (mg/kg) (d.l.=0.02 mg/kg)Avellino 49 132 93.2 91 16.8Benevento 13 98 50.42 50.00 15.67Caserta 23 101 65.03 66 15.19Napoli 6 187 70.87 57.00 38.28Salerno 18 130 56.48 55 20.66

Zn (mg/kg) (d.l.=0.001 mg/kg)Avellino 75.7 271 110.6 102.7 31.23Benevento 29.3 487 80.27 61.15 66.66Caserta 51.6 1488 116.4 84.7 140.51Napoli 24 24532 164.1 99.00 793.54Salerno 19.5 1682 196.6 128.7 202.49



Elemental distribution in the soils of Caserta urban area

The NE of Caserta and its most densely populated area showvery high Pb (up to 289 mg/kg), As (up to 41.7 mg/kg), Hg (upto 1.22 mg/kg), Cd (up to 2.85 mg/kg), Zn (up to 1375 mg/kg)and Cu (up to 275 mg/kg) concentrations, all ascribed to hightraffic flow (Lima et al. 2007). All these elements, highly toxicfor humans, exceed in many locations the trigger and actionlevels set by DM 471/99 (Fig. 4). The highly urbanized areashows relatively high concentrations for V, Co, Se, Cr and Cd;however, these values are most likely due to natural causes(Lima et al. 2007). Similarly to Benevento and Avellino, Pd andPt pollution is evident in the city centre where high traffic flowis present (Cicchella et al. 2008b).

Elemental distribution in the soils of Salerno urban area

Average concentrations major and minor element (i.e. thosemeasured in the percentage range: Al, Ca, Fe, K, Mg, Na, P, Sand Ti) are generally found within highly populated areas, whilepeaks of higher concentrations are irregularly distributed, show-ing no discernible association with any human activity orpresence.

Average concentrations of trace and ultra-trace non-pollutantelements (i.e. those in the mg/kg and ppb range but not listedas pollutants in DM 471/99: Ag, Au, B, Ba, Bi, Ga, La, Mn, Mo,Sc, Sr, Te, Th, U and W) are found mainly within inhabitedareas. Higher and peak values for most of these elements tendto be located in urban and industrial areas (sometimes close toroads with high traffic levels), suggesting a direct connectionwith human presence and activity (Fedele et al. 2007).

Table 4. Statistical parameters for trace and ultra-trace elements in the topsoils of urbanareas of Campania region and the provincial area of Napoli.


Ag (µg/kg) (d.l.=2 µg/kg)Avellino <2 423 97 80 59.2Benevento 10 948 71 36 132.2Caserta 12 2121 125 86 192.3Napoli <2 8132 242 129 419.5Salerno 13 2286 190 89 309.6

Au (µg/kg) (d.l.=0.2 µg/kg)Avellino 0.7 76.3 6.3 4.4 8.1Benevento 0.7 126.6 7.6 2.2 18.4Caserta 0.15 124 6.7 3.5 11.8Napoli <0.2 1278.6 33.4 8.9 80.9Salerno 0.7 914.7 34.1 6.1 117.9

B (mg/kg) (d.l.=1 mg/kg)Avellino 7 29 16 16 3.5Benevento 2 21 8.5 8 2.7Caserta 4 33 10 9 4.2Napoli <1 63 17.5 14 10.9Salerno 3 98 10.8 10 8.1

Ba (mg/kg) (d.l.=0.5 mg/kg)Avellino 356 950 656 651 130Benevento 20 833 273 262 122Caserta 38 724 418 428 118Napoli 9 1813 429 427 261Salerno 38 978 304 284 151

Bi (mg/kg) (d.l.=0.02 mg/kg)Avellino 0.27 0.88 0.57 0.57 0.1Benevento 0.08 0.67 0.31 0.32 0.1Caserta 0.14 1.44 0.57 0.57 0.15Napoli 0.12 35 0.69 0.47 1.56Salerno 0.08 0.76 0.34 0.34 0.14

Ga (mg/kg) (d.l.=0.1 mg/kg)Avellino 6.4 18.3 13.7 13.9 2.2Benevento 1.7 13.7 6.9 6.8 2.3Caserta 3.4 18.2 10.9 11.2 2.6Napoli 2 15.3 7.6 7.3 2.6Salerno 1.5 16.2 6.8 6.5 3.2

La (mg/kg) (d.l.=0.5 mg/kg)Avellino 32.2 96.7 62.2 62.6 10.4Benevento 8.5 64.4 32 30.7 13.2Caserta 9.4 121.4 61.2 61.1 16.3Napoli 10 108 41.6 41 10.9Salerno 4.4 143.6 35.2 33.2 20.1

Mn (mg/kg) (d.l.=1 mg/kg)Avellino 736 1661 1112 1114 133Benevento 318 4881 1173 941 745Caserta 492 1416 980 967 180Napoli 215 5923 738 720 309Salerno 210 1865 710 716 255

Mo (mg/kg) (d.l.=0.01 mg/kg)Avellino 1 3.1 1.6 1.6 0.3Benevento 0.3 2.4 0.8 0.7 0.4Caserta 0.4 3.1 0.9 0.8 0.3Napoli 0.1 20.4 1.8 1.6 1.3Salerno 0.4 20.2 2.3 1.8 2.1

Sc (mg/kg) (d.l.=0.1 mg/kg)Avellino 1.9 4.7 2.9 2.9 0.4Benevento 1.7 5.4 3.2 3.1 0.8Caserta 1 7.3 3.1 2.9 0.9Napoli 0.5 4.1 1.5 1.4 0.5Salerno 0.6 6.5 2.5 2.4 1

Table 4. continued


Sr (mg/kg) (d.l.=0.5 mg/kg)Avellino 116 299 205 208 39Benevento 53 346 133 126 50Caserta 25 316 108 105 36Napoli 13 835 214 189 131Salerno 25 326 117 111 42

Te (mg/kg) (d.l.=0.02 mg/kg)Avellino <0.02 0.09 0.04 0.03 0.02Benevento <0.02 0.17 0.05 0.05 0.03Caserta <0.02 0.1 0.03 0.03 0.02Napoli <0.02 0.56 0.07 0.05 0.05Salerno <0.02 0.11 0.02 0.02 0.01

Th (mg/kg) (d.l.=0.1 mg/kg)Avellino 7.4 32 18.8 18.2 5Benevento 1.3 25.5 10 9.5 5Caserta 1.5 39.3 16.4 16.4 6.2Napoli 1 44 13.8 13.4 5.5Salerno 0.8 29.8 9.9 9.4 6

U (mg/kg) (d.l.=0.1 mg/kg)Avellino 2 13.1 7.3 7.4 2.3Benevento 0.4 6.1 1.4 1.1 0.9Caserta 0.5 8.4 2.9 2.6 1.5Napoli 0.9 16 3.7 3.1 1.9Salerno 0.5 6.9 2.5 2.3 1.1

W (mg/kg) (d.l.=0.1 mg/kg)Avellino 0.9 3 1.8 1.8 0.4Benevento <0.1 1.7 0.6 0.5 0.3Caserta <0.1 3.9 1 1 0.4Napoli 0.3 12.2 1.3 1.2 0.8Salerno <0.1 6.5 0.8 0.8 0.6



Average and high concentrations of trace and ultra-tracepollutants (As, Be, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, Se, Sn, Tl,V and Zn, according to DM 471/99) are found almostexclusively within populated areas, industrial sites and along

roads with high traffic levels, pointing strongly towards a directcorrelation with human presence and activities.

Trigger and action levels set by Italian law are usuallyexceeded in only a few sites, with the notable exceptions of Be,

Fig. 4. Box-plots of potentially harmful elements. For each boxplot, the horizontal thick lines indicate the trigger and action levels establishedby the law DM 471/99 (Ministero dell’Ambiente 1999). AV, Avellino; BN, Benevento; CE, Caserta; NA, Napoli; SA, Salerno.


Pb, Sn and Tl which are above the limits in the majority ofsampled sites (Fig. 4) (Fedele et al. 2007). Palladium and Ptpollution is evident in all the areas where high traffic flow ispresent, such as the city centre and the industrial sector(Cicchella et al. 2008b).

CONCLUSIONS

The study of element concentrations in topsoils of the urbanareas of Campania region and the related cartographic represen-tation revealed a number of important findings as outlinedbelow.

Geochemical maps in all the examined urban areas show apositive correlation between high values of toxic elements (Sb,Cd, Hg, Pd, Pb, Pt, Cu, Zn) and the most densely populatedareas, the street network with high traffic flows, and withindustrial areas. The highest concentrations are found in theproximity of emission sources (i.e. streets, industries etc.). In theparticular case of Pb, isotopic data support the interpretationthat high traffic flows are responsible for high concentrations insoils.

In all investigated urban areas, non-residual soils from thecity centre (in most cases sampled in flowerbeds) show muchhigher concentrations compared to residual soils (sampled insuburban areas). The latter present values much closer tonatural backgrounds, with the few exceptions of some samplesprobably affected by local (point) contamination. Lead concen-trations found in the urban area of Napoli hold particularconcern, since values up to 20 times (c.2000 mg/kg) higher thanthe natural background were found. Many samples exceed thetrigger and action level of 100 mg/kg (residential/recreationaluse) set for Pb by DM 471/99. The same areas present highconcentrations of Cu, Zn, Cd, Sb and Hg, with several sitesconsidered as contaminated according to DM 471/99.

High concentrations of toxic elements (particularly As, Tl,Co and V) were also found in suburban areas. However, theirlarge areal extension and the outcropping of lithologies naturallyenriched in these elements (e.g. pyroclastic deposits, clays, greysiliceous marls) strongly suggest that these ‘anomalies’ arepossibly of geogenic nature.

High concentrations of PHE (Pt, Pd and Rh) were alsofound in soils of urban areas (particularly Napoli and Salerno).Possible sources of these elements, which are extremely toxic

when accumulated in animals and humans, are the catalyticconverters installed on motor vehicles.

The use of scientific methodologies such as EDTA digestionallowed us to prove that high concentrations (i.e. those abovenatural backgrounds) of toxic elements found in soils are, in themajority of cases, bioavailable, and hence they can easily enterthe food chain and constitute a health risk for humans.

The publication of the geochemical maps produced by theresearch group led by De Vivo, which were previously unavail-able, provides essential support for local authorities in theCampania region, and sets the reference point to evaluate anyfuture modification of geochemical parameters in soils of thisregion.

The determination of natural background levels will allow theadjustment of the existing legislation to the local situation, atleast in terms of soil pollution levels. In fact the law DM 471/99states that trigger and action levels can be modified as afunction of local known natural backgrounds.

The application of new mathematical approaches(multifractal–IDW, C–A and S–A methods), usually adopted indifferent fields (geophysics and geochemical mineral explora-tion), allowed us to produce a more effective geochemicalvisualization cartography and to determine natural backgroundsand anomalies, proving their value in the field of environmentalgeochemistry.

This research was supported by PON fund to Professor B. De Vivo(Project PETIT-OSA; OR10). We wish to express many thanks tothe reviewers of the manuscript for their helpful comments.

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Urban geochemical mapping in the Campania region (Italy)