Marine Pollution Bulletin 89 (2014) 407–416

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Marine Pollution Bulletin

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Baseline

Edited by Bruce J. Richardson

The objective of BASELINE is to publish short communications on different aspects of pollution of the marine environment. Only thosepapers which clearly identify the quality of the data will be considered for publication. Contributors to Baseline should refer to‘Baseline—The New Format and Content’ (Mar. Pollut. Bull. 60, 1–2).

Spatial patterns of metals, PCDDs/Fs, PCB

s, PBDEs and chemical statusof sediments from a coastal lagoon (Pialassa Baiona, NW Adriatic, Italy)

http://dx.doi.org/10.1016/j.marpolbul.2014.10.0240025-326X/� 2014 Elsevier Ltd. All rights reserved.

⇑ Corresponding author at: Centro Interdipartimentale di Ricerca per le ScienzeAmbientali (C.I.R.S.A.), University of Bologna, 48123 Ravenna, Italy.

E-mail address: roberta.guerra@unibo.it (R. Guerra).

Roberta Guerra a,b,⇑, Andrea Pasteris a, Seok-hyung Lee b, No-jin Park c, Gon Ok c

a Centro Interdipartimentale di Ricerca per le Scienze Ambientali (C.I.R.S.A.), University of Bologna, Italyb Department of Physics and Astronomy, University of Bologna, Italyc Department of Environment Atmospheric Science, and Dioxin Research Center, Pukyong National University, Busan, Republic of Korea

a r t i c l e i n f o a b s t r a c t

Article history:Available online 27 October 2014

Keywords:Coastal lagoonWater Framework DirectiveSedimentMercuryPolychlorinated biphenyls (PCBs)Polybrominated diphenyl ethers (PBDEs)

The European Water Framework Directive (WFD) establishes a framework for the protection and improve-ment of all water bodies including transitional waters; its final objective is to achieve at least ‘good status’by 2015. In the present work, a hierarchical sampling design was applied to analyze the influence ofanthropogenic inputs on the spatial distribution of metals, polychlorinated dibenzo-p-dioxins (PCDDs)dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs)in sediment at four areas in Pialassa Baiona coastal lagoon. In order to assess the chemical status, levelsof priority substances and other pollutants were compared with the recently developed national Environ-mental Quality Standards (EQS) and site specific background levels for metals. Levels of mercury and PCBswere particularly high and exceeded their national EQS values at all sampled areas, thus not contributingto the achievement of a good chemical status of this transitional water body according to the WFDclassification.

� 2014 Elsevier Ltd. All rights reserved.

In Europe, water protection from chemical pollution in conti- (Directive 2013/39/EU; European Commission, 2013) to establish

nental, marine and transitional water bodies is based on regularmonitoring of a selected list of dangerous substances in differentmatrices (e.g., water, sediment and biota). In this respect, one ofthe objectives of the Water Framework Directive (WFD, 2000/60/EC; European Commission, 2000) is to achieve a good chemical sta-tus for all European waters by 2015. The WFD assessment of thechemical status of a water body is based, together with the back-ground levels used as reference conditions, on compliance withEnvironmental Quality Standards (EQS) which, if met, allow thechemical status of the water body to be described as ‘good’. To sup-plement the WFD, a new amending directive has been approved

EQS limits for 33 priority substances and 8 other pollutants forwater and biota, only, but the Member States (MS) should monitorthese substances in the sediment and establish their national EQS.According to these Directives, Italy established its own sedimentEQS for priority and non-priority substances for the classificationof the ‘chemical status’ of the sediment in marine and transitionalwater bodies by ‘‘the Ministerial Decree November 8, 2010, No. 260(D.M. 260/2010)’’.

In this study, a spatial survey was conducted on metal andorganic contaminant levels including mercury, polychlorinatedbiphenyls (PCBs), polychlorinated dibenzo-p-dioxins anddibenzofurans (PCDD/Fs), and polybrominated diphenyl ethers(PBDEs) in sediments at multiple areas within a transitional waterbody, the Pialassa Baiona coastal lagoon. Chemical data wereanalyzed with respect to the existing national EQS, when available,

Fig. 1. Map of Pialassa Baiona lagoon, showing sampling sites (stars) within areas labeled by numbers (Geographic coordinates, European Datum 1950).

408 R. Guerra et al. / Marine Pollution Bulletin 89 (2014) 407–416

and to the natural background levels used as reference conditionsfor metals. Overall, there is still very little understanding of thespatial patterns of Persistent Organic Pollutants (POPs) and newemergent POPs contamination in Pialassa Baiona ecosystem anda need to understand the extent of the potential problem, toidentify potential sources and areas of concern for monitoringpurposes. Thus, in the light of above, and due to the intenseanthropic forcing in this area, this study may help to link studiedpollutants occurrence and levels with their potential sources, withimplications for the monitoring of sediment contamination in thistransitional water body, in accordance with the WFD.

Pialassa Baiona is a eutrophic micro-tidal coastal lagoon inItaly, which forms part of the Natura 2000 European networkfor nature conservation (Fig. 1). The area is a Ramsar wetland ofinternational importance, and it is included in the Special BirdProtection Areas (European Directive 79/409/EEC) and in theSpecial Areas of Conservation (European Directive 92/43/EEC).Natural and man-made changes over time have led to the existingphysiographical features comprised of shallow bodies of saline,brackish or fresh water wetlands, isolated or semi-isolated bylevees and crossed by a network of artificial channels dug in1850. The inner channels converge into a main channel connectedto the sea through the shipway channel. Salinity in the lagoon(25–35 psu) is mainly controlled by water exchange with theAdriatic Sea through this channel. The average depth varies from0.5 m in the shallowest areas to 3 m in the channels with a tidalrange variable from 0.3 to 1 m, excluding extreme events. Onaverage, the water covers an area of 10 km2, and the total watervolume is approximately 107 m3 with an estimated turnover of3 days. The lagoon receives limited freshwater inputs from fivechannels (Fig. 1) draining a watershed of 264 km2, includingurban, industrial and agricultural areas (Ponti et al., 2005). Thelagoon also receives discharges from urban and industrial sewagetreatment plants, and from two thermal power plants conveyedinto the southern channel. The main freshwater and nutrientinputs are due to runoff from the watershed and to the sewageinputs with similar mean flows of about 103 m3 d�1, and to cool-ing waters coming from two thermal power plants accounting forabout 106 m3 d�1 (Ponti et al., 2005). Phytoplankton blooms andintense growth of seaweeds (Ulva sp., Enteromorpha sp., Gracilaria

sp.) were frequently observed during the summer, especially in thesouthern part (Guerra et al., 2013; Sfriso et al., 2012), and dystrophiccrises were often recorded in the summer (Ponti and Abbiati, 2004).

Main industries bordering the southern edge of the lagooninclude plastic polymer-producing factories (e.g. polyvinyl acetate),styrene polymers, and polyvinyl chloride (PVC)), a steel metallurgyplant (chemical pickling, cold rolling, annealing, galvanizing, andpre-painting of steel coils), carbon black manufacturing, an oil seedprocessing plant, and storage systems for petroleum products, fer-tilizers, and grains. Environmental contamination and humanhealth concerns in Pialassa Baiona lagoon have been pressing inrecent decades with the discovery of higher than expected concen-trations of mercury in sediments and mussels (Cattani et al., 1999;Fabbri et al., 2001a). Sediment contamination in Pialassa Baiona hasalso been an issue in recent years with the need to widen and dee-pen natural channels to increase tidal circulation, water quality andbiological diversity, and hence dredge and appropriately dispose ofsediments that may potentially be contaminated (Guerra et al.,2007, 2009).

In the Pialassa Baiona lagoon, spatial distribution of contami-nants is affected by the location of anthropogenic inputs (Fabbriet al., 2003; Guerra, 2012), the hydrodynamic of the system andthe heterogeneity of the physical and chemical variables(Trombini et al., 2003), which could vary at a wide range of spatialscales. Hence, a hierarchical sampling design was applied toanalyze the spatial distribution of metals, PCDD/Fs, PCBs andPBDEs. Four channel areas (labeled 1–4) were selected. Areas 1and 2 were located in the southern edge of the lagoon, in the chan-nel that receives industrial/municipal wastewater discharges, witharea 1 being the closest to the point of inputs. Areas 3 and 4 werelocated northward, far from the industrial discharges. On the otherhand, areas 2 and 3 were near the seaward channels confluenceand more directly connected to the sea through the shipway chan-nel, in comparison to areas 1 and 3. Three sites, spaced 100–300 mapart, were randomly selected for each area and three sedimentreplicate samples (top 5 cm) were collected at each site by meansof a Wildco� box corer. Samples were removed from the top ofeach core using a stainless steel spoon to avoid contaminationand then distributed into separate pre-labeled, acid-washed andsolvent-rinsed glass jars with Teflon-lined caps for chemical anal-

R. Guerra et al. / Marine Pollution Bulletin 89 (2014) 407–416 409

yses, or to HDPE plastic jars for grain size analysis. Samples werestored on board ship in coolers filled with ice, and then stored at�20 �C immediately upon return to the laboratory.

All samples were analyzed for moisture, grain size, and organicmatter. Particle size distribution was determined by wet sievingthrough a series of sieves: sand (between 0.250 mm and 2 mm),fine sand (between 0.063 mm and 0.250 mm), and silt–clay(<0.063 mm), and each fraction was dried and weighted. Organicmatter was estimated by loss on ignition (LOI) using a method sug-gested by Heiri et al. (2001) with 2.0 ± 0.2 g of wet sediment driedat 105 �C for 24 h followed by ashing at 550 �C for 4 h.

A 63 lm fraction was obtained by dry sieving of samples, previ-ously oven-dried at 60 �C. Iron (Fe), Manganese (Mn), chromium(Cr), copper (Cu), nickel (Ni), lead (Pb), zinc (Zn) were analyzedon this sediment fraction by inductively coupled plasma atomicemission spectrometry (ICP-AES) (Perkin Elmer OPTIMA 3200XL),after digestion with an acid mixture (HCl, HNO3, and HF, 3:1:1 v/v); and total mercury (T–Hg) was determined by cold vapor atomicabsorption spectrometry (CVAA), according to the EPA methods3052/6010C (USEPA, 1996a, 2007a) for metals, and EPA 7471Bfor mercury (USEPA, 2007b). Analytical accuracy was achieved bythe use of blanks and certified reference material for sediment(i.e. MESS 3 from NRC, Canada) included in all series of analysis.All measured values were within ±10% of certified concentrations(92–110%), and the precision was always below 10%.

Analyses of PCDD/Fs, PCBs, and PBDEs in sediment sampleswere performed following the extraction and cleanup methodsdescribed elsewhere (Moon et al., 2008; Ok et al., 2009). Briefly,sediment samples were extracted in a Soxhlet apparatus using300 mL of 10% acetone in toluene for 20 h (DCM; ultra residueanalysis, J.T. Baker, Phillipsburg, NJ, USA). The extract was dividedinto three portions prior to the purification for PCDD/Fs, dioxin-likePCBs (DL-PCBs), and PBDEs. The first aliquot (6 mL) was spikedwith 13C-labeled internal standards of PCDD/Fs (EPA-1613LCS;Wellington Laboratories, Guelph, ON, Canada), the second aliquot(3 mL) was spiked with 13C-labeled DL-PCBs (WP-LCS; WellingtonLaboratories) for the quantification of PCDD/Fs and DL-PCBs,respectively, and the third aliquot (1 mL) with 13C-labeled BDEcongeners (MBDE-MXC and MBDE-139-IS, Wellington Laborato-ries) for the quantification of PBDEs. The extracts for PCDD/F, PCBs,and PBDEs analysis were cleaned by passing through a multi-layersilica gel column (neutral, 70–230 mesh, Wako Pure Chemicals,Tokyo, Japan) containing anhydrous Na2SO4, 10% (w/w) AgNO3-sil-ica gel, silica (0.6 g), 22% (w/w) H2SO4-silica gel, 44% (w/w) H2SO4-silica gel, 2% (w/w), silica (0.6 g) and KOH-silica. For the analysis ofthe 209 PCB congeners, a standard solution M-1668A-1-5-0.01X(Accu Standard, USA) was used (Miyata et al., 1994; Ok et al.,2009). Detailed descriptions of instrumental analyses have beenpresented elsewhere (Moon et al., 2007; Ok et al., 2009). Samples

Table 1Sediment chemical data summaries for the Pialassa Baiona lagoon – for metals and PCBsdefine the chemical status for transitional waters according to the Water Framework Direcdeviation, minimum, maximum and 50th (i.e. median value), 75th and 95th percentiles forfor PCBs and PCCD/PCDFs are based on Toxic Equivalency Factor (TEFs) (van den Berg et a

Chemical Units Range Chem

Min Max Mea

Metal Chromium (Cr) mg kg�1 53 142 84Copper (Cu) mg kg�1 13 93 38Lead (Pb) mg kg�1 4.8 40 17Mercury (Hg) lg kg�1 100 22,140 4144Nickel (Ni) mg kg�1 35 57 43Zinc (Zn) mg kg�1 56 400 123

PCBs RPCB lg kg�1 9.0 634 124RTEQs (PCDD/Fs and PCBs) ng kg�1 0.57 55 8.9

a Limit Chemical Levels (LCL) from APAT–ICRAM (2007).b Miserocchi et al. (1993).

were analyzed in batches, and QA/QC procedures to evaluateaccuracy and precision of the analytical data included surrogaterecoveries, procedural blanks, blank spike samples, laboratoryduplicates, and standard reference materials for PCDD/Fs andDL-PCBs (DX-2 and DX-3, NWRI, Wellington Laboratories).

PCDD/Fs analyses included 17 congeners for which WHO 2005Toxic Equivalency Factors (TEFs) (van den Berg et al., 2006) havebeen determined to allow calculation of Toxic Equivalent (TEQ)values. For PCBs, 209 congeners were quantified with PCB congen-ers (IUPAC numbers) 77, 81, 105, 114, 118, 123, 126, 156, 157, 167,169, and 189 representing DL-PCBs in which TEQ values were cal-culated according to the WHO 2005 TEFs for fish (van den Berget al., 2006).

Descriptive statistics were computed to illustrate the main char-acteristics of sediments and contaminants in Pialassa Baiona lagoon(Tables 1 and 2). To test for differences in sediment characteristicsand contaminant concentrations among areas and sites, a two-waynested analysis of variance (ANOVA) was applied using the GMAV5.0 software (Institute of Marine Ecology, University of Sydney,Australia). When significant differences among areas were encoun-tered, a Student–Newman–Keuls (SNK) post hoc comparison testwas also carried out. Prior to all analyses, the homogeneity of vari-ance was tested by the Cochran test, and when necessary, the datawere appropriately transformed (Underwood, 1997).

Spatial patterns for metals, PCDD/Fs, PCBs, and PBDEs insediments from Pialassa Baiona lagoon are shown in Figs. 2–4;numerical values are listed in Table 1, where EQS are available,and Table 2, where none are available. The chemical data summa-ries show that T–Hg, Cr and Zn were the most prevalent tracemetals present, with comparatively high mean and medianconcentrations (Table 1), and maximum concentrations of 22,142 and 400 mg kg�1, respectively. Concentrations of the naturallyabundant metals Fe and Mn varied within narrow ranges (Table 2).

For Cr and Ni, most samples exceeded their national EQS values,which were set at levels lower than the background values(Table 1). For T–Hg most samples exceeded both the backgroundvalue for the studied area, and the national EQS of 120 lg kg�1

and 300 lg kg�1, respectively; whilst for Pb, the majority of sam-ples were below both the background value of 24 mg kg�1 andthe national EQS of 30 mg kg�1 (Table 1).

Cu, Cr and Zn displayed the same spatial pattern, with higherconcentrations in area 1, where they exceeded the existing EQSand/or the background values (Table 1, Fig. 2). Differences amongareas, tested by ANOVA, were highly significant for Cr, Cu and Zn(p < 0.01). Post hoc comparison with SNK test showed significantlyhigher concentrations in area 1, when compared to the other areasof the lagoon; conversely, differences among areas 2–4 were notsignificant. Pb displayed a different spatial pattern with concentra-tions below the specific background and the national EQS values

for which national Environmental Quality Standards (EQS) have been established totive (WFD, 2000/60/EC; European Commission, 2000). Data show the mean, standardn = 36 samples. WHO (World Health Organization) TEQs (toxic equivalents) calculatedl., 2006).

ical summary statistics Background values EQS

n SD 50th 75th 95th

20 81 95 127 158 50a

22 31 36 87 46 529.1 16 21 28 24 306597 824 2546 19,895 120b 3005.1 43 45 51 97 3093 77 107 122 170a

167 37 189 – 814 1.7 13 45 – 2

Table 2Sediment chemical data summaries for the Pialassa Baiona lagoon – for metals, PCBs, PCDD/Fs and PBDEs for which national Environmental Quality Standards (EQS) to define thechemical status for transitional waters according to the Water Framework Directive (WFD, 2000/60/EC; European Commission, 2000) are not available. Data show the mean,standard deviation, minimum, maximum and 50th (i.e. median value), 75th and 95th percentiles for n = 36 samples. WHO (World Health Organization) TEQs (toxic equivalents)calculated for PCBs and PCCD/PCDFs are based on Toxic Equivalency Factor (TEFs) (van den Berg et al., 2006).

Chemical Units Range Chemical summary statistics

Min Max Mean SD 50th 75th 95th

Sediment Silt & clay (<0.063 mm) % 12 62 33 14 29 45 54LOI % 2.5 13 5.4 3.1 3.9 5.8 11

Metals Iron (Fe) mg kg�1 17,230 25,270 21,580 2200 21,534 23,110 24,910Manganese (Mn) mg kg�1 318 522 428 36 436 444 501

PCBs RTetra � CB lg kg�1 1.7 38 8.6 9.2 4.1 13 36RPenta � CB lg kg�1 3.2 138 30 37 11 35 130RHexa � CB lg kg�1 2.4 236 48 65 12 78 228RHepta � CB lg kg�1 1.4 165 31 44 8.3 49 145ROcta � CB lg kg�1 0.09 51 6.5 13 0.65 6.5 40Rnona + deca � CB lg kg�1 0.07 4.5 0.66 1.0 0.20 0.86 3.3RPCB TEQs ng kg�1 0.02 15 2.5 4.2 0.28 3.0 14

PCDDs/PCDFs Rtetra � CDD ng kg�1 1.2 31 6.5 8.0 2.3 12 25Rpenta � CDD ng kg�1 0.19 60 11 16 2.6 18 51Rhexa � CDD ng kg�1 8.5 848 122 210 17 157 641Rhepta � CDD ng kg�1 20 6369 825 1545 58 1136 4632ROCDD ng kg�1 64 12,344 2016 3437 178 3048 10,453Rtetra � CDF ng kg�1 4.0 126 28 34 11 47 112Rpenta � CDF ng kg�1 2.3 130 26 33 10 39 106Rhexa � CDF ng kg�1 1.8 199 29 49 6.4 28 154Rhepta � CDF ng kg�1 4.1 537 74 131 9.3 90 418OCDF ng kg�1 3.4 321 46 77 8.9 49 271RPCDD ng kg�1 96 19,641 2980 5195 252 4373 15,808RPCDF ng kg�1 16 1313 204 323 44 252 1061RPCDD/F TEQs ng kg�1 0.55 39 6.4 10 1.3 9.1 32

PBDEs Mono-nona BDEsa lg kg�1 0.33 8.0 1.8 2.3 0.58 3.4 7.8BDE-209 lg kg�1 1.22 33 7.9 9.2 3.8 8.2 32RPBDEs lg kg�1 1.6 41 9.7 11 4.7 12 37

a Target BDE congeners: BDE-3, -7, -15, -17, -28, -47, -49,-66, -71, -85, -99, -100, -119, -139, -153, -154, -183, -196, -197, -201, -203, -204, -206, -207, -208.

410 R. Guerra et al. / Marine Pollution Bulletin 89 (2014) 407–416

(24 and 30 mg kg�1, respectively), except in area 1 (Table 1, Fig. 2).Differences among areas, tested by ANOVA, were highly significant(p < 0.01). Posthoc comparison with SNK test showed significantlyhigher concentrations in areas 1 and 2, when compared to areas3 and 4; conversely, differences between area 1 and area 2, andbetween area 3 and area 4 are not significant. Conversely, Ni didnot display any spatial pattern among the four areas of the lagoon(ANOVA not significant), with concentrations systematically abovethe national EQS of 30 mg kg�1 and below the calculated back-ground value of 97 mg kg�1 (Table 1, Fig. 2).

Spatial patterns of T–Hg are analyzed in Fig. 3 also showing LOIand sediment grain size in the sampling areas of Pialassa Baionalagoon. Sediments were typically mud and sandy mud (>20% siltand clay), and had high T–Hg concentrations ranging from 100 to22,140 lg kg�1 (Table 1). In area 1, LOI was highest, sediments were>50% silt and clay, and T–Hg were approximately 10� to 100�higher than in areas 2–4, exceeding the background values of120 lg kg�1 and the national EQS of 300 lg kg�1 (Table 1).Differences among areas, tested by ANOVA, were significant forsilt–clay (p < 0.05) and highly significant for LOI and T–Hg(p < 0.001). Posthoc comparison with SNK test showed that percent-ages of LOI and silt–clay, and levels of T–Hg were significantlyhigher in area 1, when compared to other areas of the lagoon;conversely, differences among areas 2–4 were not significant.

The chemical status of sediment has been evaluated followingthe approach of Rodríguez et al. (2006) and Tueros et al. (2009)for metals (Cu, Cr, Hg, Ni, Pb and Zn), PCDD/Fs and PCBs as contam-inants. Fe and Mn were not included within the assessment,because they are considered as non-toxic metals; and PBDEs wereexcluded, although considered toxic, as quality objectives are notavailable (Long et al., 1995). According to the WFD, the chemicalstatus is referred as: ‘high status’, when non-synthetic pollutantssuch as metals are below the upper limit of the background range;

‘good status’, when they range between background level and EQS;and ‘moderate status’, when the concentrations exceed the EQS val-ues (see Table 1). This approach is based upon the national EQSestablished according the Directive 2008/105/EC for priority sub-stances and other pollutants (i.e. Hg, Ni, Pb, dioxins and dioxin-likecompounds, and Cr) (Maggi et al., 2012). Background values formetals refer to The upper background values of Cr, Cu, Pb, Ni andZn have been estimated as the 90th percentile of log transformeddata (n = 30) from a regional barrier–lagoon–estuary system inthe early Holocene (Amorosi et al., 2002; Dinelli et al., 2012). Themean background value of Hg refers to a datable long sediment corereaching pre-industrial sediments (Miserocchi et al., 1993).

T–Hg concentrations were always above the background andnational EQS values (Table 1, Fig. 3), corresponding to a moderatechemical status of the sediment. Overall, T–Hg is the most wide-spread metal contaminant in Pialassa Baiona lagoon, and the veryhigh values up to 22.14 mg kg�1 found in area 1 further substanti-ate a localized mercury hotspot in the proximity of the industrialarea. Mercury levels found in this area are equivalent, or higher,than values found in coastal lagoons generally recognized as heav-ily polluted i.e. Venice (0.5–2.51 mg kg�1; Berto et al., 2006), Mar-ano and Grado (1.22–4.49 and 9.5–14.4 mg kg�1, respectively;Faganeli et al., 2012 and references therein), Ria de Aveiro (0.04–2.33 mg kg�1; Oliveira et al., 2010), and Patos (0.02–17.84 mg kg�1; Mirlean et al., 2003). Comparably high concentra-tions were found in coastal areas downstream chlor-alkali plantsor acetaldehyde producing factories: i.e. Augusta Bay, Sicily(0.25–92 mg kg�1; Bellucci et al., 2012), Gulf of Finland (1.4–5.7 mg kg�1; Salo et al., 2008), Cartagena Bay, Colombia (0.94 and10.4 mg kg�1, Alonso et al., 2000), the Sagua la Grande River estu-ary, Cuba (0.032–1.81 mg kg�1; Olivares-Rieumont et al., 2012),the Guanabara Bay, Brazil (0.1–3.22 mg kg�1; Covelli et al., 2012)the Lenga Estuary, Chili (0.02–13 mg kg�1; Díaz-Jaramillo et al.,

Fig. 2. Mean (±SE) for chromium concentrations (mg kg�1), copper concentrations (mg kg�1), nickel concentrations (mg kg�1), lead concentrations (mg kg�1), and zincconcentrations (mg kg�1 dw) in surface sediments samples from Pialassa Baiona lagoon; areas: 1–4. National Environmental Quality Standards (EQS) and background levelswere reported for comparisons (see Table 1). Areas with same letter are not significantly different at p 6 0.05 according to SNK test.

Fig. 3. Mean (±SE) for LOI (%), silt and clay (<63 lm, %), and total mercury (T–Hg, mg kg�1) in surface sediments samples from Pialassa Baiona lagoon; areas: 1–4. Regressionof T–Hg (mg kg�1) against LOI (%), and regression T–Hg (mg kg�1) against percent silt and clay. National Environmental Quality Standards (EQS) and background levels werereported for comparisons (see Table 1). Areas with same letter are not significantly different at p 6 0.05 according to SNK test.

R. Guerra et al. / Marine Pollution Bulletin 89 (2014) 407–416 411

2013), the Ulsa estuary, India (0.46–6.40 mg kg�1; Ram et al.,2009), and the Minamata Bay (0.3–4.8 mg kg�1; Tomiyasu et al.,2006). Earlier studies on T–Hg contamination in surface sedimentsof Pialassa Baiona lagoon reported concentrations in the rangebetween 0.11 and 161 mg kg�1 (Miserocchi et al., 1993), andbetween 0.2 and 250 mg kg�1 (Trombini et al., 2003). Morerecently, T–Hg concentrations ranging from 0.4 to 5.5 mg kg�1weredetected in the central-northern area (Guerra et al., 2009), peakingup to 1.32–191 mg kg�1 in the southern area, within the channelconveying industrial and municipal wastewaters (Guerra, 2012).Recent industrial contamination by mercury is excluded, sincethe phasing out of the Hg-based technology for vinyl chloride pro-duction in the nearby chemical industry (Miserocchi et al., 1993).Recurrent hypoxic conditions during the summer (Santini et al.,2010) may limit Hg mobility and its availability to methylating

bacteria, despite high Hg contents, due to pyritization or sulfuriza-tion of organic matter and the formation of Hg binding solid org-ano-sulfides (Fabbri et al., 2001a; Covelli et al., 2011).Conversely, resuspension of Hg-contaminated sediment inducedby dredging operations or changing of redox conditions followingtranslocation, could enhance the bioavailability and mobility ofHg in Pialassa Baiona lagoon (Fabbri et al., 2001b).

Significantly higher Pb concentrations found in areas 1 and 2are at or slightly above the regional background value, which inturn, is close to the existing national EQS (Fig. 2). Except one sitewithin area 1, the chemical status of sediment could be classifiedas high/good.

Cu and Zn sediment concentrations were higher than their back-ground values only in area 1 (Fig. 2). National EQS for these metalswere not established in accordance with the WFD, and thus data

Fig. 4. Mean (±SE) for PCDDs (ng kg�1), PCDFs (ng kg�1), PCBs (lg kg�1), and PBDEs (lg kg�1) concentrations in surface sediments samples from Pialassa Baiona lagoon; areas:1–4. National Environmental Quality Standards (EQS) were reported for comparisons (see Table 1). Areas with same letter are not significantly different at p 6 0.05 accordingto SNK test.

412 R. Guerra et al. / Marine Pollution Bulletin 89 (2014) 407–416

were compared to national LCB (baseline chemical level) and LCL(limit chemical level) sediment quality guidelines (Pellegriniet al., 2002). The LCB is the concentration below which adversebiological effects were not observed in a suite of bioassays;conversely, the LCL is the concentration above which biologicaladverse effects are likely to occur according to the Probable EffectLevel (PEL) criterion of Mac Donald et al. (1996). These national sed-iment quality guidelines were developed for a set of metals fordredged material management (APAT-ICRAM, 2007). Cu and Znnot only exceeded their background values in area 1, but also theirLCL values (52 and 170 mg kg�1, respectively), thus suggesting thateffects on benthic biota inhabiting the sediments are possible oreven probable in this area (Table 1, Fig. 2). Assuming that LCL couldreplace the EQS, the chemical status of sediments in area 1 could beclassified as moderate, and for the remaining areas of the lagoon(2–4) as high. Hence, Cu and Zn show anthropic enrichment in area1, and much of this contamination is consistent with the proximityto the industrial activity. For example, the high Cu and Zn concen-trations could reflect agricultural runoff as well as industrial inputs(Miserocchi et al., 1990). Matteucci et al. (2005) reported that theonset of anthropogenic Cu inputs were recorded about 50–60 yearsago, and have decreased since the 1980s into Pialassa Baionalagoon. On the contrary, Zn showed a 3-fold increase in recent sur-face sediments, thus indicating there is a persistent Zn pollution inthe proximity of the industrial complex, possibly linked to fertiliz-ers use and metallurgical production.

Two metals (Cr and Ni) do not show anthropogenic enrichmentover the area with reference to the regional background levels(Table 1). In contrast, when comparing levels of Cr and Ni with theirnational EQS, sediments from Pialassa Baiona lagoon as a wholeseem to be affected by a diffuse contamination. According to theEQS criteria, the chemical status of sediment is classified as moder-ate; conversely, according to the regional background value, sedi-ment chemical status is classified as high. Although Crconcentrations in sediments of area 1 are slightly but significantlyhigher than other areas of the lagoon, they fell below the upperregional background level (Fig. 2). So far, there is no evidence ofanthropogenic sources of Cr into the lagoon; as a consequence wesuggest that higher concentrations are linked to higher organic mat-ter content in area 1. Concentrations of Cr and Ni are within the

ranges reported for other lagoon environments in the North AdriaticSea with low or without anthropogenic impact. For example, sedi-ments from Valli di Comacchio coastal lagoon showed Cr and Ni lev-els ranging from 32 to 89 mg kg�1, and from 51 to 86 mg kg�1,respectively (Pecora, 2001). Geochemical fingerprinting of sedimentcomposition in alluvial and coastal depositional systems around thearea of study reported Cr and Ni levels of about 20–120 mg kg�1 and20–65 mg kg�1, respectively, that point to a predominant contribu-tion from sediment of Apennine provenance (Amorosi andSammartino, 2007; Amorosi, 2012); hence, concentrations of thetwo elements in Pialassa Baiona lagoon are likely to reflect sedimentgeochemistry rather than anthropic inputs.

To analyze the probable processes affecting the spatial distribu-tion of metals (Fe, Mn, Cr, Cu, Hg, Ni, Pb and Zn), we performedSpearman rank correlation analysis with LOI. When consideringall sampling areas, all metals show highly significant positive corre-lations with LOI (p < 0.01), except Pb and Mn. When consideringareas 2–4 collectively, highly significant (p < 0.01) and significantcorrelations (p < 0.05) were found between LOI and Cr, Cu and Fe,and between LOI and Zn, respectively. When considering area 1alone, Ni, Zn, Fe show highly significantly correlation with LOI(p < 0.01), and Cu a significant correlation (p < 0.05). Anthropicinputs directly impact Area 1, where organic matter content is high-est; as consequence its not possible to establish to which extent theassociation with LOI influences the spatial patterns of metals withinPialassa Baiona lagoon. However, the significant correlations foundbetween LOI and some metals within area 1 and within areas 2–4,suggest a suspended organic matter-driven transport of contami-nants within the lagoon, thus confirming findings of previousstudies on mercury (Miserocchi et al., 1993; Fabbri et al., 2001b)and other metals (Donnini et al., 2007) in this transitional waterbody.

Total PCDD and PCDF ranged from 96 to 19,641 ng kg�1 and16–1313 ng kg�1, respectively. By far, the highest concentrations(up to >10,000 ng kg�1 of PCDD/Fs) were found in sediments fromarea 1 (see Fig. 4 and Table 2). Octachlorodibenzo-p-dioxin (OCDD)was the predominant homologue group of the PCDD/F homologueprofiles with concentrations between 64 and 12,344 ng kg�1

(Table 2). The contribution of OCDD to the total PCDD/Fs averaged61%, ranging from 53% to 68% in all sediments analyzed in the Pia-

R. Guerra et al. / Marine Pollution Bulletin 89 (2014) 407–416 413

lassa Baiona lagoon. Differences among areas, tested by ANOVA,were highly significant for PCDDs and PCDFs, and each homologuegroup (p < 0.01). Post hoc comparison with SNK test showed thatconcentrations are significantly higher in area 1 compared to otherareas of the lagoon; conversely, differences among areas 2–4 werenot significant (Fig. S1). Differences among areas, tested by ANOVA,were highly significant for tetra- to OCDD relative abundances(p < 0.01). Post hoc comparison with SNK test showed that OCDDrelative abundances are significantly higher in areas 1 and 2, thanin areas 3 and 4 (Fig. S2).

Total PCB concentrations (R209 congeners) ranged from 9 to amaximum of 634 lg kg�1, always exceeding the national EQS of8 lg kg�1 (Table 1, Fig. 4), and displayed the highest values in sed-iments inside area 1 (Table 1, Fig. 4). A more detailed analysis ofthe PCB homologue profiles shows that hexa-CBs are the mostabundant homologues ranging from 2.4 to 236 lg kg�1 (Table 2;Fig. S3). The contribution of hexa-CBs averaged 61%, ranging from53% to 68% in all sediments analyzed in Pialassa Baiona lagoon. Dif-ferences among areas, tested by ANOVA, were highly significant fortotal PCB and tetra- to deca-homologue groups (p < 0.01). Post hoccomparison with SNK test showed highly significantly higherconcentrations in area 1 compared to other areas of the lagoon;conversely, differences among areas 2–4 were not significant.Differences among areas, tested by ANOVA, were also significantor highly significant for tetra-, penta-, hepta- and octa-CBshomologue group ratios. Ratios decreased from area 1 to area 4for hepta- and octa-CBs, and increased for tetra- and penta-CBs.Conversely, hexa- and nona-deca CB homologue group ratios werenot significantly different among areas (Fig. S4).

TEQs (toxic equivalents) based on recalculated World HealthOrganization (WHO) – Toxic Equivalent Factor values (TEF, vanden Berg et al., 2006) for PCDD/Fs and PCBs varied within twoorders of magnitude, between 0.55 and 39 ng kg�1, and 0.02 to15 ng TEQ kg�1, respectively (Table 2, Fig. S6), exceeding thenational EQS of 2 ng kg�1as total TEQs (RTEQ) in �40% of the totalsamples (Table 1, Fig. S6). Differences among areas, tested byANOVA, were significant for PCBs TEQs (p < 0.05) and highly signif-icant for PCDD/F TEQs and RTEQ (p < 0.01). Post hoc comparisonwith SNK test showed significantly higher concentration in area1 when compared to other areas of the lagoon; conversely, differ-ences among areas 2–4 were not significant (Fig. S6).

According to the WFD, the chemical status for synthetic pollu-tants is referred as: ‘high status’, when concentrations are closeto zero or below the detection limit of the most advanced analyti-cal techniques in use; and a ‘good status’, when their concentra-tions are not in excess of EQS. EQS values are not available forPCDDs and PCDFs; however, a national EQS of 2 ng kg�1 RTEQ(RPCDD/Fs + PCB dioxin like as WHO–TEF; van den Berg et al.,2006) has been established by the ‘‘Legislative Decree November8, 2010, No. 260’’ (D.L. 260/2010). Sediment RTEQ always exceededthis threshold in area 1, and in some cases in areas 2 and 3 (Table 1,Fig. S6), suggesting a moderate or good chemical status ofsediments.

Despite the global distribution of PCDD/Fs, they have neverbeen intentionally produced. However, a variety of chemical andthermal processes, including the manufacture of chlorinated inter-mediates and the combustion of chlorinated materials, can resultin the formation and release of PCDD/Fs (Fiedler, 1996). In thisstudy, both the levels of PCDD/Fs and homologue profiles changedmoving away from the industrial area; the PCDD/Fs congener pro-file was characteristically dominated by OCDD (�50–70%), and rel-atively low PCDFs concentrations (Table 2, Figs. S1 and S2). Asimilar pattern has been found in the coastal environment ofQueensland, Australia (Gaus et al., 2002), in soils (Green et al.,2004) and in sediment cores from Mexico (Canedo-López et al.,2011).

PCDD/Fs levels found in Pialassa Baiona lagoon in this study(119–20,954 ng kg�1) are similar or somewhat lower than levelsfound in highly contaminated European coastal areas, i.e. Venicelagoon (16–126,561 ng kg�1; Bellucci et al., 2000), the Elbe estuary,Germany (711–169,605 ng kg�1; Götz et al., 2007), the NorwegianGrenlandsfjords (25,000–730,000 ng kg�1; Ishaq et al., 2009), andthe Finnish Gulf (430–52,900 ng kg�1; Isosaari et al., 2002),but consistently higher than in Thau lagoon, France(153–1656 ng kg�1; Castro-Jiménez et al., 2008), in the Spanishnorthern Atlantic coast (0.15–3.99 ng kg�1; Gómez-Lavín et al.,2011) and in the intertidal zone of the North Sea (0.124–3.156 ng kg�1; Danis et al., 2006). Identifying the source-specificPCDD/Fs contamination is beyond the scope of this study. As withHg, a localized PCDD/Fs hotspot in area 1 hints at an industrialsource of PCDD/Fs; homologue profiles analysis of the sedimentsindicated dominance by OCDD, which was significantly higher inthe proximity of the industrial area (Figs. 4 and S1). The increaseof lower chlorinated and the concomitant decrease of higher chlori-nated PCDDs with distance from the anthropic source could be theresult of various biotic and abiotic transformation processes, whichin turn, could result in considerable alterations of original PCDDsemission signatures. The processes involved resulted in a shifttoward higher abundance of tetra- to pentachlorinatedhomologues with increasing time after deposition and suggest adechlorination of the higher chlorinated PCDDs (Gaus et al., 2002).

PCBs levels were elevated in Pialassa Baiona lagoon, alwaysexceeding the national EQS of 8 lg kg�1, and were exceptionallyhigh in sediments at area 1, where they exceeded this thresholdby 2 orders of magnitude. According to the WFD, the chemical sta-tus of sediment in Pialassa Baiona lagoon would be classified asmoderate. As with Hg and PCDD/Fs, PCBs displayed the highest val-ues up to 634 lg kg�1 in area 1, located near the industrial com-plex, but remained at lower levels in the other areas of thelagoon (Table 1, Fig. 4). These values were comparable to levelsfound in Venice lagoon (5–2049 lg kg�1 and 4.24–239.15 lg kg�1;Frignani et al., 2001; Moret et al., 2001), Oslofjord, Norway,(1–764 lg kg�1; Oug et al., 2012), the Sado River estuary, Portugal(1.3–114 lg kg�1; Ferreira et al., 2003), the Mediterranean coastalareas of France (29–181 lg kg�1; Piérard et al., 1996), and theScheldt estuary, the Netherlands–Belgium (0.47–136 lg kg�1;Van Ael et al., 2012), ranging from heavily polluted to minimallyimpacted areas. Conversely, concentrations found in this studywere somewhat higher than those reported for Thau lagoon, France(2.53–33.32 lg kg�1; Castro-Jiménez et al., 2008), the intertidalzone of the North Sea (4.11–8.44 lg kg�1; Danis et al., 2006), theGuadiana estuary, Portugal (0.1–1.8 lg kg�1; Ferreira et al.,2003), and the Elbe estuary, Germany (2–85 lg kg�1; Wetzelet al., 2013). In a wide monitoring study on global distribution ofPCBs in the Mediterranean Sea, coastal lagoons reported PCBs lev-els between 0.9 and 5600 lg kg�1 (Gómez-Gutiérrez et al., 2007).

PCBs levels and homologue profiles changed moving away fromthe industrial area, with an increase of tetra- to penta-CBs and adecrease of the higher chlorinated PCBs. The predominant homo-logues seen in sediments were hexa > hepta > penta comprising� 80% of total PCBs (Table 2, Figs. S3 and S4). Matteucci et al.(2001) and Guerra (2012) also found these three homologues tobe the most predominant PCB homologues in sediments fromPialassa Baiona. The homologue pattern for the Pialassa Baionasamples is similar in composition to a mixture of Aroclor 1254/Aroclor 1260 (Ikonomou et al., 2002). Yet, a shift toward higherabundance of lower chlorinated homologues at increasing distancefrom the anthropogenic inputs suggests a reductive dechlorinationof the higher chlorinated PCBs, and/or higher mobility of lowerchlorinated homologues. Specific pathways and rates of PCB micro-bial dechlorinating activity have been reported in anoxic freshwa-ter, estuarine and most recently in marine sediments (Zanaroli

414 R. Guerra et al. / Marine Pollution Bulletin 89 (2014) 407–416

et al., 2012). Such a case is Pialassa Baiona lagoon, where recurrenthypoxic conditions occur during the summer months (Santiniet al., 2010).

Polychlorinated biphenyls (PCBs) are a group of chlorinated aro-matic hydrocarbons once widely used in industry as heat transferfluids, hydraulic lubricants, flame retardants, plasticizers, and asdielectric fluids in electronic components such as capacitors andtransformers. Due to their environmental toxicity and classifica-tion as persistent organic pollutants (POPs), PCB production wasbanned by the United States Congress in 1979, by the StockholmConvention on Persistent Organic Pollutants in 2001, and in Italyin 1983. In the absence of any obvious direct local sources andgiven the very elevated levels found in the proximity to the indus-trial area when compared to other areas, it is most likely that PCBspresence in Pialassa Baiona lagoon is the result of past spill/dis-charge/dumping and concomitant degradation processes that isworth further investigating.

The concentrations of RPBDE (hereafter, RPBDE refers to thesum of all detected PBDE congeners except for the congenerBDE-209) and the deca-brominated congener BDE-209 rangedfrom 0.33 to 8.0 lg kg�1 and 1.2–33 lg kg�1, respectively. As withthe PCDD/Fs and PCBs, the highest RPBDE and BDE-209 concentra-tions were found in sediments within the area 1 (see Fig. 4 andTable 2). Differences among areas, tested by ANOVA, were highlysignificant for RPBDE and BDE-209 (p < 0.01), and post hoc compar-ison with SNK test showed significantly higher concentrations inarea 1 when compared to other areas of the lagoon. The relativecontribution of the most abundant BDE congeners to the totalPBDE concentrations found in the sediments from Pialassa Baionalagoon is shown in Fig. S5. The most abundant congener detectedwas BDE-209, whose proportions ranged from 56% to 94%; nona-brominated congeners (BDE-206, -207, -208) were the secondmost abundant homologue group ranging from 3 to 22%. Of thelower brominated congeners, BDE-47 and BDE-99 were presentin the highest proportions (0.4–7%, and 0.2–9%, respectively). Nosignificant differences in the relative abundance of BDE-47, BDE-99, BDE-206, BDE-207, BDE-208 and BDE-209 were found amongthe four areas of the lagoon. To our knowledge, the occurrence ofPBDEs in sediments of the Pialassa Baiona lagoon has not beendescribed before. To determine the relative severity of PBDE con-tamination in Pialassa Baiona sediments, comparisons were madeagainst other studies where sediment PBDE concentrations havebeen measured. The concentrations of BDE-209 found in the Pia-lassa Baiona lagoon sediments (Table 2) are similar to thosereported in Danish sediments with a maximum level of21.5 lg kg�1 in Copenhagen harbour (Christensen and Platz,2001) and in North Sea sediments with 32 lg kg�1 (Klamer et al.,2005). A rapidly increasing trend in environmental concentrationsof RPBDE and BDE-209 has been reported in sediment cores fromthe Sheldt estuary, Belgium (668–8413 lg kg�1; Covaci et al.,2005), the Drammenfjord, Norway (<0.9–105 lg kg�1; Zegerset al., 2003), and the Clyde estuary, U.K. (1–2337 lg kg�1; Vaneet al., 2010). Other works had similarly shown that the highest con-centrations of RPBDE with a predominance of BDE-209 occurredunder the influence of wastewater outflows in Spain (Eljarratet al., 2005), and in France (Salvadó et al., 2012).

Although the WFD addresses and regulates the chemical statusby focusing on priority substances, there is a growing awareness ofthe need to consider emerging pollutants such as PBDEs (Vorkampet al., 2014). The ultimate goals of the WFD are achievement andpreservation of good chemical and ecological status for Europeanwater bodies. Hence, it is logical to consider aspects of PBDEs, lev-els in the Pialassa Baiona lagoon water body and use patterns. Onthe 10th of May 2009, tetrabromodiphenyl ether, and pentabro-modiphenyl, hexabromodiphenyl and hepentabromodiphenylethers were accepted by the 4th meeting of the Conference of

Parties (UNEP, 2009a) for inclusion in the Stockholm Conventionpersistent organic pollutants (POPs) list on 26th August 2009(UNEP, 2009ab). Among the 26 target BDE congeners, 15 congenerswere found in all sediment samples from the four areas, indicatingthat PBDEs are ubiquitous contaminants in Pialassa Baiona lagoon.RPBDE and the deca-brominated congener BDE-209 displayed thehighest levels in area 1 (Table 2, Fig. 4); the concentration ofBDE-209 was one order of magnitude higher than that of theRPBDE in all the sediments. The most abundant congener detectedwas BDE-209, whose proportion ranged from �60% to 90%;nona-brominated congeners (BDE-206, -207, -208) were thesecond most abundant homologue group and comprised an aver-age of 3–23% of the total PBDE in the four areas of the lagoon(Fig. S5). The relative abundance of BDE-209 observed in sedimentsfrom Pialassa Baiona lagoon is entirely consistent with the fact thatcommercial deca-BDE makes up most of the PBDE production anduse around the world and in Europe, along with the European banof octa- and penta-BDE commercial formulations in 2004 (Lawet al., 2006). Deca-BDE formulation consists mainly of BDE-209(92–97%), with a small proportion of nona-BDEs (0.3–3%) (LaGuardia et al., 2006). Deca-BDE is a general purpose flameretardant and is used in virtually any type of polymer including:polycarbonates, polyester resins, polyolefins, ABS, polyvinyl chlo-ride, and rubber. Deca-BDE combined with antimony oxide is usedin processes that require high-temperature processing such as highimpact polystyrene used in TV and computer monitor cabinets(Alaee et al., 2003). The use of Deca-BDE in electrical and electronicequipment in the EU has been banned since 1 July 2008 accordingto European Court of Justice (2008). The relative amount of nona-BDE observed here was greater than would be expected from theoriginal deca technical formulations (Alaee et al., 2003; Hoh andHites, 2005). One explanation could be that BDE-209 had under-gone photolytic and microbial debromination to yield a relativeincrease in nona-BDE, as reported by Söderström et al. (2004)and He et al. (2006) in laboratory studies.

The results of this study show that sedimentary Hg and PCBslevels in Pialassa Baiona lagoon regularly exceeded their nationalEQS values, thus representing an impediment to achieve a goodchemical status by 2015, according to the WFD classification. Crand Ni exceeded their national EQS values, but not the calculatedbackground values. The reason of this contradiction can be relatedto the ambitious national EQS values, included in the LegislativeDecree 260/2010, in relation to the site specific background levels.These findings suggest the need to re-examine these threshold val-ues. EU Member States are developing monitoring programmes inorder to establish a comprehensive overview of the ecological andchemical water status within each transitional water body. Suchmonitoring includes the assessment of biological quality elements,chemical monitoring of both organic and inorganic priority pollu-tants, and measurement of physic-chemical parameters. Threemodes of monitoring are specified in the WFD: surveillance moni-toring, aimed at assessing long-term water quality changes onwater bodies; operational monitoring, aimed at establishing thestatus of those water bodies at risk of failing to meet environmen-tal objectives; investigative monitoring, aimed at assessing causesof such failure. According to this scheme, this survey can be qual-ified as an operational monitoring. On the ecological quality statuspoint of view, the WFD requires using five classes: high for unpol-luted sites, good for slightly polluted sites, moderate for moder-ately polluted sites, poor for heavily polluted sites, and bad forextremely polluted sites. Ecological status of Pialassa Baionalagoon has been classified as poor using the AMBI index for benthicassemblages (Ponti et al., 2008), and this is in line with the chem-ical status of the sediments. This survey indicates the need of aninvestigative monitoring programme to ascertain the causes of suchecosystem deterioration, and suggests the need of management

R. Guerra et al. / Marine Pollution Bulletin 89 (2014) 407–416 415

interventions for the achievement of a good status of this transi-tional water body.

Acknowledgements

Part of this study was financially supported under the‘Executive Programme of Scientific and Technological Cooperationbetween Italy and Korea’ for the years 2010–2012 (Grant No.KR10MO4). Massimo Ponti, Elena Lo Giudice and Simona Bonaiutiare acknowledged for their skillful assistance in the field and in thelaboratory, and we would also like to thank the personnel of theItalian Ceramic Centre for use of their facilities and invaluable help.

Appendix A. Supplementary material

Supplementary data associated with this article can be found, inthe online version, at http://dx.doi.org/10.1016/j.marpolbul.2014.10.024.

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