Human impacts can change marine ecosystem bothdirectly and indirectly causing, in the first case, overexploitation and lossof habitat, while, in the latter ones, changes in interactions in the food weband in the structure of environment (Goulletquer et al. 2014). Coastal areasare particularly subject to human pressure, since in this zone are located mostof the anthropogenic activities. Human pressure can modify the natural statusof of physical, chemical, and biological components that characterize marineecosystem (Reiss et al. 2014). Regular monitoring of sediment quality is animportant pursuant to assessing the possible influence of anthropogenicpressure on ecosystem quality (Romeo et al. 2015) and give information tosupport management in order to reach a Good Environmental Status (GES) in the MarineStrategy Framework Directive (MSDF) perspective. Moreover, as reported bynumerous studies (Cozar et al.
2014; Nuelle et al. 2014), the analysis ofmarine sediments is important in the evaluation of the emerging pollutantssuch as microplastics, that tend to accumulate in the sea-bottom. At present, microplasticsrepresent a major global concern affecting all world oceans, defined in theMSFD as D10 into different categories including the plastic debris. Thismaterial, in the environment is subject to a combination of physical,biological and chemical processes that reduce its structural integrity (Cole etal. 2011) producing high densities of smaller debris as microplastics (1-5 mm).As reported in the Guidance on Monitoring of Marin Litter in European Saes(2013) the monitoring of litter in seafloor cannot consider all coastal areasbecause of limited resources, for this reason also opportunistic approach (i.e. data from other research activityin the harbour) could be used to improve the existing monitoring plans.
Recentstudies testify that microplastic can became a threat of biodiversity, becominga vector for the introduction of non-native marine species to new habitats onfloating (Barnes 2002; Derraik 2002; Winston 1982). In addition, because oftheir size, microplastics are considered bioavailable to organisms throughoutthe food web (Thompson et al. 2004). When ingested, plastics release chemicals compound(nonylphenols, polybrominated diphenyl ethers, phthalates and bisphenol A)together with adsorbed hydrophobic pollutants (i.e. PCBs, TBT, DBT, MBT). Even if, the use of these pollutants wasbounded, their extensive use in the past and their low water solubility makethem persistent and able to accumulate both in sediments and in biota (Harrisand Wiberg 2002) and are measured at significantlevels in marine ecosystems and marine food webs (D’Alessandro et al. 2016).
The sea-floor integrity (D6, MSFD) reflectscharacteristics of the sea bottom influencing, in particular, the structure andfunctioning of communities living on the sea floor (benthic ecosystems). Disturbanceof the bottom may change structure of benthos community damaging mainly sensiblespecies causing biodiversity loss. Macroinvertebrates, due to their skill to modifytheir community patterns in relation to natural and anthropogenic stress(Warwick1988) , are considered great biondicators of marine ecosystem (Warwick 1993;Romeo et al.
2015). Actually, a lot of benthic indices based on structure of macrofaunalcommunities were created to assess the ecological quality status (EcoQ) tosupport data for MSFD, e.g. AMBI (Borjaet al. 2000), M-AMBI (Muxika et al. 2007), BENTIX (Simboura and Zenetos 2002), BOPA(Dauvin and Ruellet 2007).
These indices, based on the subdivision of speciesin different ecological groups, return a value of environmentalquality/disturbance status.The aim of this paperis to carry out a quality assessment of a high polluted harbour of the Ionian sub-regionand Central Mediterranean Sea through a multidisciplinary approach thatintegrate biotic and abiotic parameters, in order to give data to improve themonitoring plan of the MSFD regarding shallow waters. Material and methodsStudy area The Augusta site islocated in the MSFD Ionian sub-region of central Mediterranean Sea, in aharbour area with a high marine traffic activity. This area hosted a variety ofdifferent chemical and petrochemical refining plants, a commercial harbour anda basis of the Italian Navy and NATO activities (Sprovieri et al. 2007). The harbouris closed to the South and East by artificial dams.
Two main inlets connectharbour with open sea: the south-east and the east inlet. The basin ischaracterised by three different circulation systems: eastern inlet, dominatedby a tidal current with a northward flowing, south eastern inlet, characterizedby flowing parallel to the coast; the northern portion of the basin, instead,is characterized by shallow seabed and scarcely affected by active currents (Sprovieri et al. 2007;Romano et al. 2013).
Three small riversflow in the area, Mulinello in the North and Marcellino and Cantera in the centralpart of the bay (Fig. 1). Due to the dangerous contamination of air, seawater,and marine biota documented in this area, Augusta coastal area has beenincluded by the Italian Government in the national remediation plan (G.U.R.I.,L. 426/1998) and evaluated by the World Health Organization as providing a highenvironmental risk.
Sampling activities and laboratory analysesSamples were carriedout from hard and soft bottoms during the summer of 2013 (Table1, Figure1). Softbottom samples were collected by means of a Van Veen grab (0.1 m2)along four transects perpendicular to coastline at three different depths (5,10 and 20 m). For each sampling site four replicates were carried out, three ofwhich were used for biological analysis, and one for the environmentalcharacterization following the methods described in D’Alessandro et al. (2016)and Romeo et al. (2015).
Sediment characterization was carried out according toBuchanan and Kain (1971) and the percentage of pebble, gravel, sand, silt andclay was determined according to the ternary Wentworth scale (Wentworth, 1922).Plastics debris wereclassified according to Guidance on Monitoring of Marine Litter in EuropeanSeas (JRC EU, 2013) adapted. Four size classes were identified: microplastics(1-5 mm), macroplastics (5-10 mm), megaplastics (10-20 mm) and plastics (>20 mm) (Barnes 2002; Claessens et al. 2011). Microplastics were extractedaccording to Alomar et al. 2016 with some modifications. For each sample, 1 Kgof sediment was dried at 50° C for 48 h and then sieved for 15 min by means stainlesssteel sieves with mesh diameter of: 20; 10; 5; 0.
5; 0.1 mm. For each fraction,plastics were extracted by density separation method and then, sediments wereobserved under Stereomicroscope (Zeiss Discovery.V8) with optical enhancementwith a maximum magnification of 80x. Accurate precautions have been used toprevent contamination during all phases of study according to Woodall et al.2015. Hard bottom samples were carried out by SCUBA diving, scraping a surfaceof 400 cm2 from two pillars within refinery.
Three samples werecollected at three different depths (0.5; 6.0 and 15.0 m), for a total amountof 9 samples per pillar. Chemical analysiswere conducted taking into account contaminants included in the MSFD monitoringplane and other contaminants of interest taking into account, accordingliterature, different typologies of anthropogenic impact of the study area (Falandyszet al. 2006; Fang et al.
2003; Reli? et al. 2016) . Trace elements (Cd, Hg, Pb,As, Cr) and other elements (Cu, Ni, and Zn) concentrations were determinedthrough Inductively Coupled Plasma-Mass Spectrometry (ICP-MS; mod. AgilentTechnologies), according to the US-EPA 6020A method. Quantifications of PCBs(congeners 28, 52, 77, 81, 101, 118, 126, 128, 138, 153, 156, 169, 180) wereconducted following US-EPA 8082A/2007 standard method. PAHs (acenaphthene,acenaphthylene, anthracene, dibenzo(a,h)anthracene, benzo(b)-fluoranthene,benzo(a)pyrene, benzo(ghi)perylene, benzo(k)fluoranthene, chrysene,dibenzo(a,h)anthracene, fluoranthene, indeno(1,2,3,)pyrene, naphthalene,phenanthrene, pyrene, perylene, acenaphthene) were determined according toUS-EPA Method 8270D. The chemical analyses of butyltins (BT) in the surfacesediments were conducted according to a modified method from Binato et al.
(1998) and Morabito et al. (1995). Tributyltin (TBT), dibutyltin (DBT),monobutyltin (MBT) and total butyltins (?BT) were determined as described in Romeoet al. (2015) and D’Alessandro et al.
(2016). All results of chemical analysiswere calculated on dry weight (d.w.), trace elements were expressed in µg/Kg,persistent organic pollutants in mg/Kg, while the butyltins concentrations wereexpressed as ng Sn g-1.In order to characterise thebenthic communities, the main biodiversity indices were calculated: number ofspecies (S), Shannon’s index (H’), and Pielou’s evenness (J) (Magurran 1991).Benthic indices (i.e. AMBI, M-AMBI,Bentix and BOPA) were calculated to evaluate the environmental status on softbottom fauna on abundance of each species.
AMBI and M-AMBI were calculated by means of AMBI index software(version 4.0, available at www.azti.es); BOPA index and its relativeenvironmental quality were calculated using the revisited formula proposed byDauvin and Ruellet (2007).