Temporal trends of metals in benthic invertebrate species from the Balearic Islands, Western Mediterranean

Temporal trends of metals in benthic invertebrate speciesfrom the Balearic Islands, Western Mediterranean

S. Deudero a,*, A. Box a, D. March a, J.M. Valencia b, A.M. Grau b,J. Tintore c, J. Benedicto d

a Laboratorio de Biologia Marina and GOI-IMEDEA (CSIC/UIB), Guillem Colom, Campus Universitari,

Ctra. de Valldemossa, km 7.5, 07122 Palma de Mallorca, Spainb C/Foners, 10. Direccion General de Pesca, Conselleria d’Agricultura i Pesca, Govern Balear, Spain

c Grup d’Oceanografia Interdisciplinar (GOI), Institut Mediterrani d’Estudis Avancats-CSIC/UIB, Miquel Marques 21, 07195 Esporles, Spaind Grupo de Estudio de la Contaminacion Marina-Instituto Espanol de Oceanografıa, C/Varadero, 1, 30740 San Pedro del Pinatar, Murcia, Spain

Very few studies have been carried out on marine pollu-tion in the Balearic Islands in the Western Mediterranean.In this region, the principle sources of pollutants are likelyto be harbours and marinas, agriculture and constructionmaterials. To date, only one study of polycyclic aromatichydrocarbons (PAHs) has been performed in sedimentsamples from Mallorca and Menorca, showing values frompristine or clear water masses far from the influence of pol-lution sources (Baumard et al., 1998). The aim of this studywas to utilise marine invertebrate species for the provisionof baseline information on concentrations of metal con-taminants, together with the temporal patterns observedduring a 10 year period.

Sample collection was carried out at four locations aroundthe Balearic Islands: two locations off the island of Menorca(BAL 1/01 and BAL 1/02), and two stations (BAL 1/03 andBAL 1/04) off the island of Mallorca (Fig. 1). The study sitesare production zones for aquaculture of molluscs and othermarine invertebrates (Ministerio de Agricultura, Pesca y Ali-mentacion. Orden 22/09/2005). The first location (BAL 1/01)was the Port of Mahon, with an expected human impactlinked to the city of approximately 28,000 inhabitants. InMallorca, production sites for mollusc mariculture arelocated in the Bay of Palma where harbour activities, sewageloads and other anthropogenic impacts are related to a rela-tively high population (approximately 376,000 inhabitants).

Samples were collected from 1991 to 2005. Several com-mercial invertebrate species were chosen as they are regu-larly exploited for human consumption at the localmarkets. The studied species included five mollusc bivalvespecies (Mytilus galloprovincialis, Venus verrucosa, Lithoph-

aga lithophaga, Ostrea edulis, Chamelea gallina) and oneechinoderm, the sea urchin Paracentrotus lividus. The sam-pling period was April–June period, linked to commercialextraction times.

Once the specimens had been collected, they were rinsed,measured, weighed and deep frozen at �20 �C until analy-

sis. To minimise size-related variation (Boyden, 1977), ashell length of 50 ± 5 mm was selected for M. galloprovin-

cialis, 20 ± 5 mm for C. gallina, 77.15 ± 1 mm for O. edulis,66 ± 7 mm for L. lithophaga, 39.23 ± 5 for V. verrucosaand 42.62 ± 3.8 mm carapace diameter for P. lividus. Forbivalves species, the mantle cavity liquid was discarded,by leaving the shells open and in a vertical position for5 min, and the byssus was totally removed. The whole softtissue was taken for analysis, triturated with Ultraturraxand freeze-dried. After the freeze-drying processes, sampleswere homogenised and stored until analysis. The full bodytissues of P. lividus were used for analyses.

Determination of trace metal content followed the spec-ifications of the National (Ministerio de Sanidad y Con-sumo. Orden 2/08/91) and European legislation (Directive2001/22/EC, for mercury levels). Tissue samples were trea-ted by a wet digestion with nitric acid, followed by metalanalyses using graphite furnace atomic absorption spec-trometry (AAS) (Varian Spectra A-10). Concentrations ofPb, Zn, Cu, Cd, Ni, Cr and Ag were determined in anair–acetylene flame. Mercury concentrations were mea-sured by cold vapour atomic absorption spectrometry.Arsenic was determined by colorimetry and complexationwith silver diethyl dithiocarbamate. To avoid contamina-tion, all chemicals were suprapure and glassware, plasticdevices and materials used in the manipulation of sampleswere flushed for 12 h with 6 NHCl and subsequently rinsedwith deionised water. Similarly, blank solutions were alsoprepared with suprapure chemical reagents. Metal concen-trations were calculated using calibration curves of stan-dard solutions. Samples were dried at 110 �C with afurnace to obtain the dry weight.

Quality assurance was primarily secured through paral-lel analyses of certified referenced material and participationin inter-calibration exercises, including QUASIMEME.The certified reference material used for bivalves was Myti-lus edulis tissue (CRM no. 278, Community Bureau ofReference). Z values (Z is between jZj 6 2) obtained inthe inter-calibration exercise for a mussel matrix were asfollows: Z =�1.52 for Hg, Z = 1.74 for Cd, Z =�1.36 forPb, Z =�0.41 for Cu, and Z =�1.52 for Zn (Pedersen et al.,1997).

* Corresponding author. Tel.: +34 971173138; fax: +34 971173184.E-mail address: [email protected] (S. Deudero).

Baseline / Marine Pollution Bulletin 54 (2007) 1523–1558 1545

Temporal variations in metal contents for each inverte-brate species were calculated by one way ANOVA.Comparison of bioaccumulation between species at thesame sampling site was contrasted by analysis of variance.Dissimilarities in metal concentrations between locationsand years for each metal were calculated for L. lithophaga

by analysis of variance.To allow a comparison of total metals at the sampling

stations, the metal pollution index (MPI) was applied(Usero et al., 2005):

MPI ¼ ðCf1 � Cf2 � � �CfnÞ1=n

where Cfn is the metal concentration n in the sample.In order to compare our results with previous values, we

adjusted the above equation excluding the values from Agand considering the other eight metals.

Mytilus galloprovincialis: Mean metal concentrationthroughout the 10 years of study in M. galloprovincialis

decreased in the following order: Zn > Cu > Pb >Ni > As > Cr > Ag > Hg > Cd (note that this order didchange in some years, such as in 1994, which showed higherlevels of Hg; see Fig. 2). Metal concentrations in M. gallo-

provincialis are shown in Table 1. Mean Zn concentration(124.5 mg kg�1 dw) was similar to previous data for non-polluted areas (Corsi et al., 2002; Table 1). Our resultsshow high levels of Cu, only exceeded by the NW Mediter-ranean (Romeo et al., 2003), Atlantic & MediterraneanFrance (RNO, 1991, 2000) and Galician Rias (Beiraset al., 2003). Cu mean values (21.2 mg kg�1 dw) in ourstudy were similar to high values found in the VeniceLagoon (Widdows et al., 1997), and statistically significantdifferences were found between years. Relatively high levelsof Pb in M. galloprovincialis were detected when compared

to Mediterranean areas such as the Tyrrhenian Sea (Contiand Cecchetti, 2003), the Venice Lagoon (Widdows et al.,1997), NE Italy (Eisler, 1981) and the French south Medi-terranean coast (RNO, 1991). Nickel values were lowerthan elsewhere and similar to the non-polluted GalicianRias (Beiras et al., 2003; Table 1). Cr values were low com-pared with other Mediterranean areas and were within therange of the south Mediterranean French coast (Andralet al., 2001). The mean Hg concentrations averagedthrough the 10 years of study were relatively high(0.78 mg kg�1 dw) and statistically significant differenceswere found between years (ANOVA, p < 0.05). M. gallo-

provincialis from the BAL1/03 station showed significanttemporal differences in arsenic concentrations (ANOVA,p < 0.05) with a decreasing tendency throughout the periodof study.

Lithophaga lithophaga: Mean metal concentrationsvalues decreased in the following order: Zn > Cu > Pb >Ni > Cd > Cr > Ag > As > Hg and Zn > Cu > Pb > Ni >Cr > Cd > As > Ag > Hg in Mallorca (Table 2). The high-est values of Zn, Cu, Cr, As, Ag and Hg were found inMallorca while the other metals presented higher concen-trations in Menorca (Table 2).

Temporal variations show a reducing trend in mostmetals (Fig. 3). L. lithophaga (from the BAL1/02 sta-tion) showed statistically significant differences betweenyears in Cr concentrations (ANOVA, p < 0.05) with atemporal reduction of this metal. Significant differencesbetween years were found in arsenic (ANOVA, p < 0.01)for BAL1/03 with a sharp drop in Cr levels between 1993and 1995.

Venus verrucosa: Metal concentrations decreased inthe order Zn > Cu > Pb > Ni > As > Cr > Cd > Ag > Hg.Temporal variations were only significantly different for

Fig. 1. Sampling stations for benthic invertebrates in the Balearics.

1546 Baseline / Marine Pollution Bulletin 54 (2007) 1523–1558

Nickel (ANOVA, p < 0.05; Fig. 4), although As and Crshowed a clear decreasing trend.

Chamelea gallina: This species showed the highest Aglevels analysed (<0.01–11.17 mg kg�1 dw; Table 2). Metalconcentration trends decreased in the following order:Zn > Cu > Ag > Pb P Ni > Cr > As > Cd > Hg (Fig. 5)

with statistical differences between years in As (ANOVA,p < 0.05). Concentrations of Pb, Cd, Cr, Zn, Hg and Niin C. gallina were higher than those reported in previousstudies (Storelli and Marcotrigiano, 2001; Usero et al.,2005), while Cu, Zn and As mean concentrations were allwithin the range obtained from the Spanish Atlantic coast,

0

5

10

15

20

25

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

mg

/kg

dry

wei

gh

t

Cr As Ni

0

50

100

150

200

250

300

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

mg

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2.5

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mg

/kg

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Cd Hg Ag

Fig. 2. Metal concentrations (Pb, Zn, Cu, Cd, Cd, Ni, Cr, As, Hg and Ag) in Mytilus galloprovincialis in the Port of Mahon (BAL 1/01). Error barsrepresent standard errors.

Baseline / Marine Pollution Bulletin 54 (2007) 1523–1558 1547

Table 1Mean (minimum and maximum) heavy metal concentrations in Mytilus galloprovincialis (in ppm dw)

Species Location Pb Cd Cu Cr Hg Ni Zn As Ag Reference

Mytilus galloprovincialis Balearic Islands(BAL 1/01)

9.98(3.3–18.6)

0.66(0.25–1.70)

21.2(5.9–58.3)

4.6(0.7–14.8)

0.78(0.13–2.21)

6.8(0.7–35.2)

124.5(48.9–316.7)

5.4(0.8–11.0)

0.90(0.26–7.14)

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Italy 1.47–3.90 0.66–2.43 6.58–16.38 0.3–0.49 90.15–234.0 Corsi et al. (2002)NW Mediterranean(clean area)

0.91–0.97 4.1–5.4 174–153 Romeo et al. (2003)

NW Mediterranean 0.53–1.01 3.1–202.3 128–394 Romeo et al. (2003)Spain–SouthMediterranean

2.45(0.5–11.2)

0.6(0.2–1.25)

5.45(2.6–11.85)

0.15(0.05–1.80)

216(86.0–423.5)

Benedicto et al. (2003)

France–Mediterranean 3.24(0.1–83.2)

0.87(0.1–36.2)

7.3(2.5–52.2)

0.18(0.02–1.24)

155(43–615)

RNO (1991)

France-Mediterranean 2.62(0.1–34.6)

0.9(0.03–2.62)

5.9(2.3–29.7)

0.1(0.03–0.6)

153.3 RNO (2000)

France–Mediterranean 1.8a

(0.7–2.8)1.2a

(0.9–3.7)4.1a

(2.9–9.2)0.2a

(0.1–0.5)123.3a

(85.2–178.8)Andral et al. (2001)

France–Mediterranean 1.0b

(0.5–5.4)0.9b

(0.1–5.85)4.1b

(2.9–9.2)3.9b

(1.0–7.5)0.1b

(0.05–0.34)4.7b

(2.0–10.6)148.3b

(116.1–203.2)20.0b Andral et al. (2001)

Galician Rias 0.3–5.4 0.20–0.77 6.8–11.3 2.2–16.1 0.10–0.58 0.85–6.5 85–207 7.1–13.7 Beiras et al. (2003)Galician Rias(contaminated)

5.7–6.1 29.9 45.7 0.58–0.63 19.0 447 Beiras et al. (2003)

N&NW Atlantic–Spain (0.52–8.22)c (0.36–2.84)c (4.42–9.65)c (0.08–0.88)c (144–462)c Besada et al. (2002)Atlantic France 2.3

(0.15–13.3)1.17(0.2–11.7)

7.3(0.9–33.9)

0.13(0.02–0.83)

94(24–546)

RNO (1991)

Atlantic France 2.18(0.6–6.8)

0.9(0.01–2.5)

7.2(5–9.9)

0.1(0.01–0.3)

113.4(40–407)

RNO (2000)

Mancha Chanel France 1.61(0.4–4.9)

1.1(0.01–6)

6.7(4.2–14.5)

0.1(0.01–0.47)

79.8(30–289)

RNO (2000)

South Atlantic Portugal (1.3–3.1) (4.8–7.0.) (0.37–0.77) (189–398) Machado et al. (1999)NE Italy 0.64–3.29d 0.21–0.29d 1.26–1.48d 14.6–27.4d Majori et al. (1978)NE Italy 2.7–117 0.4–6 2.4–15.5 0.5–29 97–644 Eisler (1981)N Adriatic Sea 0.19d 0.137d 1.57d 20.8d Martinic et al. (1984)NE Italy 0.48–5.74d 0.12–0.42d 0.50–3.26d 6.90–42.20d Favretto et al. (1987)Venice Lagoon 6.18–80.26 0.05–4.54 5.08–20.89 0.37–20.38 82–185 Widdows et al. (1997)Tyrrhenian Sea (Italy) 1.67–2.49 0.33–0.49 5.51–11.50 0.46–1.31 123–180 Conti and Cecchetti (2003)Spain 1.1–3d 17.3–75.8d Rodriguez et al. (1995)Spain 0.37c Hernandez et al. (1986)Black Sea (Turkey) 7.21–9.1 <0.06–7.58 4.02–24.07 78–512 Topcuoglu et al. (2002)UK 15.1–40.9 0.6–5.7 5.0–42.9 110–368 Giusti et al. (1999)

Mussels and oysters Indicative ofcontamination

3.2 3.7 2.5 0.23 3.4 16 Cantillo (1998)

Mussels Indicative ofcontamination

10 200 0.75 Cantillo (1998)

a Standarised at condition index of 0.124 lg/g or ng/g dw.b Standarised at condition index of 0.24 lg/g or ng/g dw.c Median.d Wet weight.

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Table 2Mean (minimum and maximum) heavy metal concentrations in marine invertebrates (in ppm dw)

Species Location Pb Cd Cu Cr Hg Ni Zn As Ag MPI Reference

Paracentrotus lividus Balearic Islands(BAL 1/03)

3.0(0.8–6.7)

0.67(0.14–1.59)

4.9(1.6–7.5)

1.6(0.4–3.2)

0.14(0.03–0.38)

1.7(0.8–2.7)

40.3(5.7–74.5)

1.6(0.7–4.1)

1.68(0.17–5.78)

1.7(0.9–3.0)

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Apulian coast(Italy)

0.86(0.10–2.65)

0.24(0.10–0.65)

5.19(1.90–14.60)

0.10(n.d.-0.16)

157.13(103.8–249.9)

Storelli et al.(2001)

NWMediterranean

1.38–2.02a,c 0.24–0.49a,c 2.68–3.18a,c 0.88–1.59a,c 0.05–0.25a,c 124–161a,c Warnau et al.(1995)

NWMediterranean

0.74–3.02a,c 0.15–0.93a,c 1.03–3.80a,c 0.90–2.16a,c 53–271a,c Warnau et al.(1998)

Lithophaga lithophaga Balearic Islands(BAL 1/02)

9.2(2.5–26.5)

2.21(0.99–5.22)

14.9(5.9–22.9)

2.1(0.5–4.8)

0.23(0.11–0.44)

4.3(2.0–2.7)

212.2(157.2–309.3)

0.9(0.7–1.3)

0.98(0.29–3.06)

3.9(3.2–4.9)

This work

Balearic Islands(BAL 1/03)

7.9(3.0–21.5)

1.73(0.16–2.33)

18.4(7.8–38.5)

2.8(0.4–6.9)

0.25(0.17–0.34)

3.3(0.4–6.7)

341.9(120.8–642.3)

1.3(0.6–5.8)

1.05(0.24–3.95)

4.1(2.3–6.0)

This work

Venus verrucosa Balearic Islands(BAL 1/01)

7.1(1.8–19.1)

1.23(0.24–5.00)

22.6(4.4–53.8)

3.3(0.4–8.3)

0.62(0.15–1.88)

5.2(0.8–9.9)

88.1(44.8–172.7)

4.3(0.9–17.7)

0.92(0.28–5.32)

4.5(2.3–10.5)

This work

Adriatic Sea 1.52b

(1.08–1.98)0.73b

(0.43–1.07)Storelli andMarcotrigiano(2001)

Chamelea gallina Balearic Islands(BAL 1/04)

3.3(0.9–12.9)

0.99(0.21–2.61)

22.0(8.7–70.9)

2.2 (0.5–7.5) 0.26(0.12–0.49)

3.2(0.5–9.6)

90.7(31.5–283.9)

1.8(0.6–12.1)

4.57(<0.01–11.17)

3.0(1.6–5.1)

This work

0.52(0.15–1.90)

0.15(0.04–0.38)

3.48(1.60–12.30)

0.36(0.10–1.31)

0.04(0.02–0.07)

0.48(0.10–1.14)

14.30(5.87–49.20)

0.26(0.11–1.00)

0.69(<0.01–1.49)

This work

South AtlanticSpain

0.74–1.92 0.29–0.38 9.2–90 0.24–1.22 <0.01–0.19 1.41–2.23 61–92 5.3–8.3 1.4–3.3 Usero et al.(2005)

Adriatic Sea 0.12b

(0.09–0.19)0.09b

(0.07–0.12)Storelli andMarcotrigiano(2001)

Ostrea edulis Balearic Islands(BAL 1/02)

7.5(2.1–17.3)

1.29(0.34–3.91)

451.7(0.8–1444.0)

3.3(0.8–11.0)

0.92(0.15–2.20)

3.6(0.8–7.5)

1458.2(204.5–3404.8)

10.6(0.8–19.0)

2.91(0.45–9.68)

9.7(2.2–15.7)

This work

UK coast(contaminated)

5.6 2055 10890 0.6 Bryan et al.(1985)

Crassostrea gigas French coast(clean area)

2.7–9.6 RNO (2001)

French coast(contaminated)

9.3–14.0 RNO (2001)

French coast(clean area)

0.7–2.3 73–210 1418–2237 RNO (1995)

French coast(contaminated)

6.7–75.0 220–1041 2782–4964 RNO (1995)

Oysters Indicative ofcontamination

300 4000 5 Cantillo (1998)

Mussels and oysters Indicative ofcontamination

3.2 3.7 2.5 0.23 3.4 16 Cantillo (1998)

(continued on next page)

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although maximum values of Zn were higher in the Bale-aric Islands than from the Atlantic coast (Usero et al.,2005; Table 2).

Ostrea edulis: This species showed the highest Cu, Znand As concentrations (Table 2). Metal concentrationtrends decreased in the order Zn > Cu > As > Pb > Ni>Cr > Ag > Cd > Hg (Fig. 6) with statistically significantdifferences between years for Pb, Cu, As and Ag (ANOVA,p < 0.05). Data from previous studies on O. edulis andCrassostrea gigas are summarised in Table 2. Our resultsfor Cd, Cu and Zn were slightly lower than those reportedfor O. edulis from the polluted UK coast (Bryan et al.,1985), but with higher levels for Ag. However, levels ofAg, Cd and Zn in our study were all within the rangeobtained for C. gigas from the non-polluted French coast(RNO, 1995, 2001). Our Cu levels were similar to thoseobtained for C. gigas from the polluted French coast(Rodriguez et al., 1995).

Paracentrotus lividus: This invertebrate showed the low-est Pb, Cr, Hg, Ni and Zn concentrations (Table 2). Metalconcentrations decreased in the order Zn > Cu > Pb >Ni � Ag P As � Cr > Cd > Hg (Fig. 7) showing statisti-cally significant differences between years in Ag concentra-tions (ANOVA, p < 0.05). Data obtained from previousstudies for P. lividus are summarised in Table 2. Our Hgvalues were within the range obtained for other NW Med-iterranean localities (Warnau et al., 1995a; Storelli et al.,2001), while Zn mean concentrations were lower than thosereported by Warnau et al. (1995b), Warnau et al. (1998)and Storelli et al. (2001). Pb, Cd and Cr were all withinthe range of Warnau et al. (1998), but were higher thanWarnau et al. (1995a) and Storelli et al. (2001). Cu valueswere higher than those reported in Warnau et al. (1998),but were within the range obtained from the Apulian coast(Storelli et al., 2001).

Metal pollution index (MPI): Values of the MPI rangedfrom 0.9 to 15.7 for the six invertebrate species withtemporal series (Fig. 8). High values were associated withO. edulis (MPI = 15.7) and V. verrucosa (MPI = 10.5), cor-responding to the first years of the present monitoring(1992 and 1993) in Menorca. For M. galloprovincialis,MPI ranged from 2.0 to 9.6 with a mean value of 5.1. Mostspecies showed a decrease in MPI from the year 2000onwards, with the exception of L. lithophaga withMPI < 4. Significant temporal variations were found forV. verrucosa (ANOVA, p < 0.05) and M. galloprovincialis(ANOVA, p < 0.01) from the BAL1/01 station (Mahon),with higher values in 1992 and 1994, followed by a decrease(Fig. 8a). M. galloprovincialis MPI values have not beencritical for human consumption since 1995, as they werefound to be lower than the polluted Galician Rias and sim-ilar to mussel production areas in Galicia (Beiras et al.,2003). There were no temporal MPI differences for Mall-orca stations with values ranging from MPI = 6 (L. lith-ophaga in 1996) to MPI = 1 (C. gallina in 2000) forbivalves, and with the lowest MPI value found for P. lividus

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1550 Baseline / Marine Pollution Bulletin 54 (2007) 1523–1558

A comparison of the MPI values between species showsstatistical differences for BAL1/02 between O. edulis and L.

lithophaga (ANOVA; p < 0.01) (Fig. 8b) and for BAL1/03between L. lithophaga and P. lividus (ANOVA; p < 0.01)(Fig. 8c). O. edulis (MPI = 2.2–15.7) showed higher valuesthan C. gallina and Donax trunculus, probably linked to the

high bioaccumulation capacity of metals such as Cu andZn, rather than to the possible pollution load since thebivalve L. lithophaga presented significantly lower values(3.2–4.9).

Background levels of metal pollutants in the marineenvironment of the Balearic Islands are non-existent. Pos-

Fig. 3. Metal concentrations (Pb, Zn, Cu, Cd, Cd, Ni, Cr, As, Hg and Ag) in Lithophaga lithophaga off the East Coast of Menorca (BAL 1/02) and in theBay of Palma (BAL 1/03). Error bars represent standard errors.

Baseline / Marine Pollution Bulletin 54 (2007) 1523–1558 1551

sible sources of contaminants to the water column mayinclude harbour and associated activities as well as agricul-ture and urban loads, but industrial inputs are almost neg-ligible. The geomorphology of the Port of Mahon, anarrow natural harbour, produces a low water renewal thatprobably enhances low dispersal rates of pollutants. Sev-

eral studies have highlighted the greater capacity of metalbioaccumulation in oysters compared to mussels, whilemussels appear to be more sensitive to metal pollution(Funes et al., 2006). This fact may explain why musselsshow a clear MPI trend with time and significant differencesincluding the decrease of heavy metals in Menorca waters.

0

20

40

60

80

100

120

140

160

180

200

1992 1993 1994 1995 1996 1997 1998 1999 2000

mg

/kg

dry

wei

gh

t

Pb Cu Zn

0

2

4

6

8

10

12

14

16

18

20

1992 1993 1994 1995 1996 1997 1998 1999 2000

mg

/kg

dry

wei

gh

t

Cr As Ni

0

1

2

3

4

5

6

1992 1993 1994 1995 1996 1997 1998 1999 2000

mg

/kg

dry

wei

gh

t

Cd Hg Ag

Fig. 4. Metal concentrations (Pb, Zn, Cu, Cd, Cd, Ni, Cr, As, Hg and Ag) in Venus verrucosa in the Port of Mahon (BAL 1/01). Error bars representstandard errors.

1552 Baseline / Marine Pollution Bulletin 54 (2007) 1523–1558

The invertebrate species analysed showed a prevalenceof the essential metals Zn and Cu in most samples inaccordance with other bivalve studies (Szefer et al., 1997;Wong et al., 2000). Moreover, O. edulis showed a bioaccu-

mulation of Pb which, in our study, might be linked to anti-fouling paints, fuels, and incinerator plants.

Our results are similar to previous data obtained else-where in waters considered to be of good quality (Tables

0

50

100

150

200

250

300

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

mg

/kg

dry

wei

gh

t

Cu Zn

0

2

4

6

8

10

12

14

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

mg

/kg

dry

wei

gh

t

Cr As Ni Pb

0

2

4

6

8

10

12

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

mg

/kg

dry

wei

gh

t

Cd Hg Ag

Fig. 5. Metal concentrations (Pb, Zn, Cu, Cd, Cd, Ni, Cr, As, Hg and Ag) in Chamelea gallina at S’Arenal (BAL 1/04). Error bars represent standarderrors.

Baseline / Marine Pollution Bulletin 54 (2007) 1523–1558 1553

1–3). The exception was M. galloprovincialis during the firstyears of sampling at Mahon harbour, which showed simi-lar values to those reported from the highly polluted Venicelagoons.

Comparing our data with European and Spanish legisla-tion, the levels of Cd and Hg in all the benthic invertebratesanalysed did not exceed existing limits (Table 3), except for

some samples of O. edulis, which for most of the periodstudied were not commercially utilised for human con-sumption due to parasitic haemocytosis (an infection bythe protist Bonamia ostreae; Valencia, personal communi-cation). Lead concentrations exceeding legislation limitswere detected on isolated occasions in the non-commercialspecies L. lithophaga. The results for M. galloprovincialis

0

500

1000

1500

2000

2500

3000

3500

1991 1992 1993 1994 1995 1996 1997

mg

/kg

dry

wei

gh

tm

g/k

g d

ry w

eig

ht

mg

/kg

dry

wei

gh

t

Cu Zn

0

2

4

6

8

10

12

14

16

18

1991 1992 1993 1994 1995 1996 1997

Pb As Ni

0

2

4

6

8

10

12

1991 1992 1993 1994 1995 1996 1997

Cd Hg Ag Cr

Fig. 6. Metal concentrations (Pb, Zn, Cu, Cd, Cd, Ni, Cr, As, Hg and Ag) in Ostrea edulis off the East Coast of Menorca (BAL 1/02). Error bars representstandard errors.

1554 Baseline / Marine Pollution Bulletin 54 (2007) 1523–1558

were within the range of data obtained in other monitoringprograms (Benedicto et al., 2003; RNO, 2000; Table 3).

Acknowledgements

The authors are indebted to the Colegio de Farmaceuti-

cos de les Balears for analytical procedures. This study was

partly financed by the Interreg Medoc IIIB, UE Project:‘Development d’un reseau de surveillance de la qualite des

eaux cotieres par des biointegrateurs pour la protection

durable de la Mediterranee Occidentale (MYTILOS)’. Theauthors D. March and A. Box received a fellowshipsponsored by the MYTILOS project Interreg Medoc

IIIB.

0

10

20

30

40

50

60

70

80

1995 1996 1997 1998 1999 2000 2001 2002 2003

mg

/kg

dry

wei

gh

tm

g/k

g d

ry w

eig

ht

mg

/kg

dry

wei

gh

t

Pb Cu Zn

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

1995 1996 1997 1998 1999 2000 2001 2002 2003

Cr As Ni

0

1

2

3

4

5

6

7

1995 1996 1997 1998 1999 2000 2001 2002 2003

Cd Hg Ag

Fig. 7. Metal concentrations (Pb, Zn, Cu, Cd, Cd, Ni, Cr, As, Hg and Ag) in Paracentrotus lividus in the Bay of Palma (BAL 1/03). Error bars representstandard error.

Baseline / Marine Pollution Bulletin 54 (2007) 1523–1558 1555

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Table 3Mean (minimum and maximum) heavy metal concentrations in marine invertebrates (in ppm dw)

Species Location Pb Cd Cu Hg Reference

Mytilus galloprovincialis Balearic Islands(BAL 1/01)

1.58(0.44–2.91)

0.10(0.05–0.17)

3.54 (1.08–12.25) 0.12(0.02–0.28)

This work

Venus verrucosa Balearic Islands(BAL 1/01)

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0.15(0.04–0.63)

3.25 (0.80–8.50) 0.08(0.02–0.18)

This work

Chamelea gallina Balearic Islands(BAL 1/04)

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0.15(0.04–0.38)

3.48 (1.60–12.30) 0.04(0.02–0.07)

This work

Paracentrotus lividus Balearic Islands(BAL 1/03)

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0.14(0.04–0.33)

1.07 (0.46–1.70) 0.03(0.01–0.10)

This work

Ostrea edulis Balearic Islands(BAL 1/02)

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0.20(0.07–0.43)

82.17 (0.16–268.00) 0.13(0.03–0.28)

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Lithophaga lithophaga Balearic Islands(BAL 1/02)

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2.75 (1.03–5.00) 0.04(0.02–0.08)

This work

Lithophaga lithophaga Balearic Islands(BAL 1/03)

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Mytilus galloprovincialis Andalucia, 91–03 0.49(0.10–2.24)

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Benedicto et al.(2003)

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RNO (2000)

Regulations(ppm ww)

1.5(EC 221/2002)

1.0(EC 466/2001)

20 (60 oyster and wedge clam)(Ministerio de Sanidady Consumo. Orden 2/08/91)

0.5(EC 466/2001)

Puerto de Mahón (BAL1/01)

0

2

4

6

8

10

12

14

16

1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 20022003 2004 2005 2006

MP

I

Costa Este de Menorca (BAL1/02)

0

2

4

6

8

10

12

14

16

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001

MP

I

Bahía de Palma (BAL1/03)

0

2

4

6

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10

12

14

16

MP

I

S'Arenal (BAL1/04)

0

2

4

6

8

10

12

14

16

MP

I

Fig. 8. Metal pollution index (MPI) for invertebrates in the Balearic Islands. Chamelea gallina (d), Mytilus galloprovincialis (j), Venus verrucosa (n),Paracentrotus lividus (s), Lithophaga lithophaga (m), Ostrea edulis (h). Error bars represent standard errors.

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0025-326X/$ - see front matter � 2007 Published by Elsevier Ltd.

doi:10.1016/j.marpolbul.2007.05.012

1558 Baseline / Marine Pollution Bulletin 54 (2007) 1523–1558