Giulio Mariani

Persistent Organic Pollutants in Mediterranean Seawater and Processes Affecting their Accumulation in Plankton

The Mediterranean and Black Seas are unique marine environments subject to important anthropogenic pressures due to riverine and atmospheric inputs of organic pollutants. Here, we report the results obtained during two east-west sampling cruises in June 2006 and May 2007 from Barcelona to Istanbul and Alexandria, respectively, where water and plankton samples were collected simultaneously. Both matrixes were analyzed for hexaclorochyclohexanes (HCHs), hexachlorobenzene (HCB), and 41 polychlorinated biphenyl (PCB) congeners. The comparison of the measured HCB and HCHs concentrations with previously reported dissolved phase concentrations suggests a temporal decline in their concentrations since the 1990s. On the contrary, PCB seawater concentrations did not exhibit such a decline, but show a significant spatial variability in dissolved concentrations with lower levels in the open Western and South Eastern Mediterranean, and higher concentrations in the Black, Marmara, and Aegean Seas and Sicilian Strait. PCB and OCPs (organochlorine pesticides) concentrations in plankton were higher at lower plankton biomass, but the intensity of this trend depended on the compound hydrophobicity (K(OW)). For the more persistent PCBs and HCB, the observed dependence of POP concentrations in plankton versus biomass can be explained by interactions between air-water exchange, particle settling, and/or bioaccumulation processes, whereas degradation processes occurring in the photic zone drive the trends shown by the more labile HCHs. The results presented here provide clear evidence of the important physical and biogeochemical controls on POP occurrence in the marine environment.

Atmospheric input of POPs into Lake Maggiore (Northern Italy): PBDE concentrations and profile in air, precipitation, settling material and sediments

Large lakes are sinks for many chemical pollutants but the role of the atmosphere in delivering PBDEs (polybrominated diphenyl ethers) is not well known. In this study we estimated inputs of PBDEs from the atmosphere to Lake Maggiore and the delivery via settling material to accumulated bottom sediments. Sampling consisted of one simultaneous week of air and bulk deposition during Spring 2005, an integrated 4-month period of collected settling material (via sediment trap), and superficial bottom sediments near the sediment trap deployment and tributary mouths of the lake. Concentration of total PBDEs (Sigma 8) in the sediments ranged between 0.06 and 27 ng g(-1), and two different patterns were observed. One pattern was dominated by BDE-47 and BDE-99 and a second by BDE-209. The latter pattern suggested input from local source(s). Total PBDEs in air were 107 pg m(-3) with a pattern dominated by BDE-47. The bulk deposition rate of total PBDEs for precipitation was measurated to be 17.6 ng m(-2) day(-1) where BDE-209 exhibited the highest concentration. For aquatic settling material the flux was 3.57 ng m(-2) day(-1) and was dominated by congeners BDE-47 and BDE-99. The bulk deposition and settling material fluxes were in the same range for the less brominated congeners, while for the hepta- and deca-brominated PBDEs the fluxes in the settling material were one order of magnitude lower. This suggests different sedimentation processes among congeners and/or the presence of local sources that influence the relative distribution in water column.

PCDD, PCDF, PCB, PAH, cadmium and lead in roadside soil: relationship between road distance and concentration

Abstract PCDD, PCDF, PCB, PAH, cadmium and lead were measured in soil samples taken at several distances from the road. The concentrations of all these pollutants markedly decreased within about 20 metres from the carriageway. A significant correlation appeared between lead and the other pollutants. These data indicates that traffic is the major source of roadside environmental pollution, not only for lead and cadmium, but for several organic pollutants too.

“De novo” synthesis of PCDD, PCDF, PCB, PCN and PAH in a pilot incinerator

Abstract PCDD, PCDF, PCB, PCN, PCT and PAH concentrations were determined in different points inside a fluid-bed pilot plant, from the furnace to the stack. The behavior of most of these micropollutants was similar. There was a general drop of levels in the post-combustor, followed by an increase during cooling, and a second fall in the abatement system. The concentrations of the different micropollutants in the various sampling points were correlated with PCDD concentrations.

Atmospheric Occurrence and Deposition of Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans (PCDD/Fs) in the Open Mediterranean Sea

The overall objective of this work is to provide the first evaluation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) occurrence and deposition to Mediterranean open seawater. sigma2,3,7,8-PCDD/F air (gas+aerosol) concentrations over the Mediterranean Sea ranged from 60 to 1040 fg m(-3). The highest value (1555 fg m(-3)) was measured in a reference sample taken in the SW Black Sea. No consistent trend regarding the diel cycle of PCDD/Fs was observed. PCDD/Fs transported to the open sea waters from continental areas and across the Atlantic as well as ship emissions may be significant sources to the open Mediterranean. Seawater concentrations in the Mediterranean ranged from 42 to 64 fg L(-1). The sigma2,3,7,8-PCDD/F dry deposition fluxes in the Marmara and Black Seas (210 kg year(-1)) are from 2 to 55 times higher than dry fluxes in the Mediterranean Sea (4-156 kg year(-1)). Analysis of estimated diffusive air-water fluxes and air/water fugacity ratios show that a net volatilization of some PCDD congeners is feasible. However, evidence of a net absorption flux for the rest of PCDD/F is found. When both atmospheric deposition processes are considered together the open Mediterranean Sea is a net sink of PCDD/F, due to the importance of dry deposition fluxes of aerosol-bound PCDDFs.

Atmospheric input of POPs into Lake Maggiore (Northern Italy) : PCDD/F and dioxin-like PCB profiles and fluxes in the atmosphere and aquatic system

The delivery and accumulation of PCDD/Fs and dioxin-like PCBs (DL-PCBs) as recorded in sediments from the Lake Maggiore (LM) in Northern Italy and the influence of the atmosphere in contaminating this subalpine ecosystem were studied. PCDD/Fs (17 congeners) and DL-PCBs (12 congeners) concentrations, congener profiles and fluxes in air, bulk deposition, aquatic settling material and surface sediments are presented. Our strategy was to obtain surface sediment from areas near riverine inputs and in the depositional basins, settling material in sediment traps at one site and air, aerosol and bulk deposition profiles. PCDD/F concentrations in air of 25 WHO-TEQ fg m(-3) and DL-PCBs of 7 WHO-TEQ fg m(-3) were measured. Bulk atmospheric deposition yielded 140 and 28 WHO-TEQ pg m(-2) per week for dioxins/furans and DL-PCBs, respectively. Aquatic settling material exhibited concentrations of 11 WHO-TEQ pg g(-1) for PCDD/Fs and 2 WHO-TEQ pg g(-1) for DL-PCBs. Weekly settling material fluxes of 50 WHO-TEQ pg m(-2) and 10 WHO-TEQ pg m(-2) were obtained for PCDD/Fs and DL-PCBs, respectively. PCDD/Fs concentrations in surface sediments varied from 0.1 to 17 WHO-TEQ pg g(-1) whereas values ranged from 0.03 to 6 WHO-TEQ pg g(-1) for DL-PCBs. The concentrations obtained in the environmental compartments studied suggest a situation of low level contamination. PCDD/Fs and DL-PCBs congener profiles in atmospheric air, bulk deposition, aquatic settling matter and surface sediment point to an important if not dominant contribution from atmospheric deposition to Lake Maggiore, especially derived from wet deposition of aerosol-bound PCDD/Fs and DL-PCBs. Flux estimates support this hypothesis.

PCDD/Fs in ambient air in north-east Italy: The role of a MSWI inside an industrial area

The stack gases of a municipal solid waste incinerator (MSWI), and ambient air were sampled in four locations around the plant for the analysis of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs). The sampling area was close to an industrial area near Trieste, in north-east Italy. The purpose of the study was to estimate the impact of the MSWI emissions and to distinguish the contribution of these emissions from other potential emission sources in the industrial area. PCDD/F atmospheric concentrations were similar to those generally detected in urban-rural areas with one location about 2-3 times more contaminated than the others. Since the most contaminated location was inside the industrial area but upwind of the MSWI, principal component analysis (PCA) was used to establish whether other sources were the cause. This analysis clearly showed that a local steel plants emission was the main source of PCDDs/Fs in ambient air. This study highlights the usefulness of multivariate data analysis such as PCA to identify, among different potential emission sources, the one really responsible for the contamination.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in River Po sediments

The River Po is the main Italian river draining one of the most populated and industrialised regions in Italy. As part of a monitoring project to assess environmental quality in the River Po, we measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in bottom sediments collected along the whole course of the river, from the spring to the delta, downstream from the confluence of its main tributaries. The aim was to investigate the level of contamination in the main Italian river and the contribution of contaminant loads from the subbasins. Composite sediment samples were collected in summer and winter surveys in low-flow water conditions and analysed by HRGC-HRMS for PCDD and PCDF homologue groups and for the 2,3,7,8-substituted congeners. The spatial trend observed in the Po River for PCDD and PCDF concentrations varied depending on the load of contaminants received from the tributaries and the processes of sedimentation. The sum of PCDD and PCDF concentrations, and the toxic equivalent content, ranged from 121 to 814 and from 1.3 to 13 ng/kg dry weight sediment, respectively. These levels of contamination seem lower than in the sediments of rivers draining highly industrialised areas. The PCDD and PCDF homologue profiles in all the samples were very similar, suggesting a common source of this contamination in the River Po. Principal component analysis suggested that widespread sources, such as urban runoff and domestic wastewaters, are probably the main cause of these levels of PCDDs and PCDFs.

Concentrations of PCDD and PCDF in different points of a modern refuse incinerator

Abstract PCDD and PCDF were measured in different points of a modern incinerator of urban solid waste, from the post-combustor to the stack. PCDD and PCDF concentrations increased steeply while the flue gas cooled from 1000 to 270°C. Abatement with electrofilters and a water tower was effective in reducing the concentrations of these micropollutants. The values for PCDD concentrations in the gas phase were (in ng/Nm 3 ) 2.85 after the post-combustor, 64.12 after the boiler and 1.75 at the stack entrance.

Synthesis and destruction of PCDD and PCDF inside a municipal solid waste incinerator

PCDD and PCDF were measured in several points inside a modern municipal solid waste incinerator. In fly ash the concentrations of these micropollutants increased during cooling of the flue gas, corresponding to a trend already reported for other plants, while in the vapour phase they decreased. This finding is discussed in relation to the incinerator characteristics.