Evaluation of sequentially-coupled POP fluxes estimated from simultaneous measurements in multiple compartments of an air-water-sediment system

Bulk atmospheric deposition fluxes, air-water exchange fluxes, particle settling fluxes out of the upper water column, sediment trap fluxes in deep waters, and sediment burial fluxes of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were simultaneously measured in the Koster Fjord, eastern Skagerak, on the Swedish west coast. The aim of the study was to compare the magnitude and direction of the compound fluxes in the system in order to diagnose key fate processes. The PCB and PAH fluxes via net atmospheric deposition, settling particles out of the surface and through deep waters, as well as into the accreting underlying sediments were shown to be remarkably similar, agreeing within a factor of a few for any given target compound. Fluxes of all PCB and PAH target compounds remained fairly constant with water column depth. Thus there was no evidence for net desorption from sinking particles. The net unidirectional and near balancing of vertical fluxes suggests a net transport of PCBs and PAHs from the atmosphere to the continental shelf sediments in the Koster Fjord, which is consistent with the hypothesis that the shelf sediments are important sinks for these compounds.     

Occurrence of PAHs, PCBs and organochlorine pesticides in the Tonghui River of Beijing, China

Tonghui River, a typical river in Beijing, People's Republic of China, was studied for its water and sediment quality, by determining the levels of 16 polycyclic aromatic hydrocarbons (PAHs), 12 polychlorinated biphenyls (PCBs) and 18 organochlorine pesticides in water and sediment samples. Total PAHs, PCBs and organochlorine pesticides concentrations in water varied from 192.5 to 2651 ng/l, 31.58-344.9 ng/l and 134.9-3788 ng/l, respectively. The total PAHs, PCBs and organochlorine pesticides concentrations in surficial sediments were 127-928 ng/g, 0.78-8.47 ng/g and 1.79-13.98 ng/g dry weight, respectively. The results showed that the concentration of these selected organic pollutants in sediment was higher than those in surface water. It may be due to the fact that organic hydrophobic pollutants tend to stay in the sediments. The PAHs were dominated by 2-, 3-ring components in water samples and by 3- and 4-ring compounds in sediment. For organochlorines, alpha-HCH, delta-HCH, Heptachlor, Endosulfan II, DDT are the major organochlorine pesticides in water while Heptachlor, Dieldrin and DDE composed of 95% of total organochlorine pesticides in sediment. For HCHs (HCHs=alpha-HCH+beta-HCH+gamma-HCH+delta-HCH), the predominance of alpha-HCH of total HCHs were clearly observed in water and sediment. PCB18, PCB31 and PCB52 were predominant in water, on average these compounds collectively accounted for 67% of total PCBs. But in sediment, the predominant compounds were PCB28, PCB31 and PCB153, which accounted for 71% of total PCBs in sediment. The levels of micro pollutants in our study areas were compared with other studies.     

Chlorinated and polycyclic aromatic hydrocarbons in riverine and estuarine sediments from Pearl River Delta, China

Spatial distribution of chlorinated hydrocarbons [chlorinated pesticides (CPs) and polychlorinated biphenyls (PCBs)] and polycyclic aromatic hydrocarbons (PAHs) was measured in riverine and estuarine sediment samples from Pearl River Delta, China, collected in 1997. Concentrations of CPs of the riverine sediment samples range from 12 to 158 ng/g, dry weight, while those of PCBs range from 11 to 486 ng/g. The CPs concentrations of the estuarine sediment samples are in the range 6-1658 ng/g, while concentrations of PCBs are in the range 10-339 ng/g. Total PAH concentration ranges from 1168 to 21,329 ng/g in the riverine sediment samples, whereas the PAH concentration ranges from 323 to 14,812 ng/g in the sediment samples of the Estuary. Sediment samples of the Zhujiang River and Macao harbor around the Estuary show the highest concentrations of CPs, PCBs, and PAHs. Possible factors affecting the distribution patterns are also discussed based on the usage history of the chemicals, hydrologic condition, and land erosion due to urbanization processes. The composition of PAHs is investigated and used to assess petrogenic, combustion and naturally derived PAHs of the sediment samples of the Pearl River Delta. In addition, the concentrations of a number of organic compounds of the Pearl River Delta samples indicate that sediments of the Zhujiang river and Macao harbor are most likely to pose biological impairment.     

Occurrence of polychlorinated biphenyls (PCBs) together with sediment properties in the surface sediments of the Bering Sea, Chukchi Sea and Canada Basin

The spatial distribution and potential source of polychlorinated biphenyls (PCBs) in surface sediments from Bering Sea, Chukchi Sea, and Canada Basin and the relationship between PCBs and sedimentary properties including grain size, water content, loss on ignition, total organic carbon, and black carbon were explored. ΣPCBs (the sum of the detected PCB congeners) concentrations fluctuated in the study area, ranging from 22-150, 60-640 and 24-600 pg g(-1) dry weight for the Bering Sea, Chukchi Sea, and Canada Basin. A similar homologue pattern was observed at different locations, with tri-chlorinated PCBs being the dominant homologue, implying that the PCBs came mainly from the atmospheric transportation and deposition and ocean current transportation. No apparent co-relationships between PCB concentrations and sediment properties were obtained, indicating that the distribution of PCBs was not only controlled by their source, but also by the multi-factors such as atmospheric transport and depositing, mixing, partitioning and sorption in the water column and sediments.     

Persistent toxic substances in remote lake and coastal sediments from Svalbard, Norwegian Arctic: Levels, sources and fluxes

Surface sediments from remote lakes and coastal areas from Ny-Ålesund, Svalbard, Norwegian Arctic were analyzed for polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). Relatively high levels of PAHs were encountered from several lakes from Ny-Ålesund, which were within the range of levels reported for European high mountain lakes and some urban/industrialized areas in the world, pointing to the role of remote Arctic lakes as potential reservoir of semi-volatile organic compounds. Specific patterns of PBDEs were observed, showing higher concentrations of lower brominated compounds such as BDE-7, 17 and 28. Estimated surface sediment fluxes of PAHs in Ny-Ålesund remote lakes were similar to those observed for some European high mountain lakes. The current PAH levels in sediments from three lakes exceeded Canadian sediment quality guidelines, suggesting the presence of possible risks for aquatic organisms and the need for further studies.     

Vertical fluxes and accumulation of PCBs in coastal sediments of the Río de la Plata estuary, Argentina

Settling particles and underlying sediments collected at 1, 2.5 and 4 km along offshore transects in the urbanized sector of the Río de la Plata were analyzed to evaluate the sources and accumulation of PCBs. Total PCB concentrations range from <0.1 to 100 ng g(-1) and include variability associated to North-South and offshore gradients reflecting the impact of coastal discharges. Highest concentrations were recorded in the industrialized Central area close to Buenos Aires (61+/-37 ng g(-1) at 1 km) relative to cleaner northern stations (3.6+/-2.2 ng g(-1)) and southward sites (37+/-2.8 ng g(-1)), affected by transport of particulate PCBs by coastal currents. Sediment traps deployed in the Central area revealed large depositional fluxes of total matter (361+/-124 gm(-2)day(-1)) and PCBs (26+/-19 microg m(-2)day(-1)) and high sedimentation rates (5.0+/-1.7 cm yr(-1)). Uniform PCB concentrations (66-89 ng g(-1)) down to 20 cm in sediment cores suggest continued PCB discharges during the last 4 years. PCB composition was dominated by hexa (43+/-6.4%), hepta (23+/-5.1%) and pentachlorobiphenyls (21+/-5.5%) with lower proportions tri-tetra (7.4+/-5.4%) and higher chlorinated congeners (5.1+/-3.3%). A consistent weathering pattern with loss of 3-5 chlorobiphenyls and enrichment in higher chlorinated PCBs corresponding to a shift from a 1:1 to a 1:3 1254:1260 Aroclor mixture, was observed offshore. A principal component analysis performed with the relative contribution of PCB congener classes confirmed the offshore weathering pattern indicating that transformer oils containing Aroclor 1254-1260 are the most probable sources. Sediment inventories, sediment trap fluxes and Fugacity II calculations indicate an accumulation approximately 500-800 kg PCB in superficial sediments of this coastal environment.     

Oxygen,carbon, and nutrient exchanges at the sediment–water interface in the Mar Piccolo of Taranto (Ionian Sea,southern Italy)

In the shallow environment, the nutrient and carbon exchanges at the sediment–water interface contribute significantly to determine the trophic status of the whole water column. The intensity of the allochthonous input in a coastal environment subjected to strong anthropogenic pressures determines an increase in the benthic oxygen demand leading to depressed oxygen levels in the bottom waters. Anoxic conditions resulting from organic enrichment can enhance the exchange of nutrients between sediments and the overlying water. In the present study, carbon and nutrient fluxes at the sediment–water interface were measured at two experimental sites, one highly and one moderately contaminated, as reference point. In situ benthic flux measurements of dissolved species (O₂, DIC, DOC, N-NO₃ ^?, N-NO₂ ^?, N-NH₄ ⁺, P-PO₄ ^3?, Si-Si(OH)₄, H₂S) were conducted using benthic chambers. Furthermore, undisturbed sediment cores were collected for analyses of total and organic C, total N, and biopolymeric carbon (carbohydrates, proteins, and lipids) as well as of dissolved species in porewaters and supernatant in order to calculate the diffusive fluxes. The sediments were characterized by suboxic to anoxic conditions with redox values more negative in the highly contaminated site, which was also characterized by higher biopolymeric carbon content (most of all lipids), lower C/N ratios and generally higher diffusive fluxes, which could result in a higher release of contaminants. A great difference was observed between diffusive and in situ benthic fluxes suggesting the enhancing of fluxes by bioturbation and the occurrence of biogeochemically important processes at the sediment–water interface. The multi-contamination of both inorganic and organic pollutants, in the sediments of the Mar Piccolo of Taranto (declared SIN in 1998), potentially transferable to the water column and to the aquatic trophic chain, is of serious concern for its ecological relevance, also considering the widespread fishing and mussel farming activities in the area.     

Florida seagrass habitat evaluation: a comparative survey for chemical quality

Contaminant concentrations were determined for media associated with 13 Florida seagrass beds. Concentrations of 10 trace metals were more commonly detected in surface water, sediment and two seagrass species than PAHs, pesticides and PCBs. Concentrations of copper and arsenic in surface water exceeded Florida aquatic life criteria more frequently than other trace elements. Total organic carbon, mercury, chromium, zinc, total chlordane, total PAHs, total PCBs, DDD and DDE were significantly greater in seagrass-rooted sediments than adjacent non-vegetated sediments. Total DDT, DDD, DDE, total chlordane, arsenic, copper and nickel exceeded proposed sediment quality guidelines at six of 13 grass beds. Pesticides, PAHs, and PCBs were below detection in seagrass tissues. Mercury, cadmium, nickel, lead and silver were detected in 50% or more of the tissues for Thalassia testudinum (turtle grass) and Halodule wrightii (shoal grass). Spatial, interspecific and tissue differences were usually an order of magnitude or less.     

Sources of PCDD/Fs, non-ortho PCBs and PAHs in sediments of high and low impacted transboundary rivers (Belgium-France)

PAHs, PCDD/Fs and non-ortho PCBs have been assessed in Yser and Upper-Scheldt river sediments. Higher contamination levels were observed in the Upper-Scheldt sediments: maximum concentrations for the 16 US-EPA PAHs, PCDD/Fs and non-ortho PCBs respectively amount to 8.9 mg kg⁻¹, 12 ng TEQ kg⁻¹ and 5.1 ng TEQ kg⁻¹. Diagnostic PAH ratios in sediments and atmospheric samples suggest that the PAH compounds are from pyrolytic origin, more specifically combustion processes. The huge consumption of coal in cokes-ovens and smelters and its use for house-heating in Northern France, although decreasing during the last decades, are in support of that suggestion. PCDD/F fingerprints in sediments and deposition material indicate that OCDD is the dominant congener. In addition use of pentachlorophenol (PCP) in the past led to a minor contribution of PCDD/Fs in our sediment samples. Non-ortho PCBs form a substantial fraction of the total TEQ concentrations observed in the sediments. Since the 1980s and 1990s a substantial reduction of the PCDD/F sediment concentrations is observed, but this is not the case for the PAHs.     

Mobility of heavy metals from polluted sediments of a semi-enclosed basin: in situ benthic chamber experiments in Taranto’s Mar Piccolo (Ionian Sea,Southern Italy)

In situ benthic flux experiments were conducted at two stations in the Mar Piccolo of Taranto (Italy), one of the most industrialised and contaminated coastal areas of the Mediterranean. Sediments of the two stations are notably different in their trace metal content, with a station closer to a Navy harbour showing higher mean concentrations of almost all investigated metals (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn). Conversely, both stations are characterised by significant Hg contamination, compared to the local baseline. Results of a sequential extraction scheme on surface sediments suggest a relatively scarce mobility of the examined metals (Zn > Ni > Cr > As > Cu > Pb). A Hg-specific extraction procedure showed that most of the element (93.1 %) occurs in a fraction comprising Hg bound to Fe/Mn oxi-hydroxides. Reduction of these oxides may affect Hg remobilisation and redistribution. Porewater profiles of dissolved trace metals were quite similar in the two sites, although significant differences could be observed for Al, Cu, Fe and Hg. The highest diffusive fluxes were observed for As, Fe and Mn. Mobility rates of several trace elements (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn) were directly measured at the sediment–water interface. Results from benthic in situ incubation experiments showed increasing dissolved metal concentrations with time, resulting in higher fluxes for Cu, Fe, Hg, V and Zn in the most contaminated site. Conversely, fluxes of Mn, Ni and Pb were comparable between the two stations. The estimated flux of Hg (97 μg m^?2 day^?1) was the highest observed among similar experiments conducted in other highly contaminated Mediterranean coastal environments. Benthic fluxes could be partially explained by considering rates of organic matter remineralisation, dissolution of Fe/Mn oxy-hydroxides and metal speciation in sediments. Seasonal and spatial variation of biogeochemical parameters can influence metal remobilisation in the Mar Piccolo area. In particular, metals could be promptly remobilised as a consequence of oxygen depletion, posing a serious concern for the widespread fishing and mussel farming activities in the area.     

Diffusion of PAH and PCB from contaminated sediments with and without mineral capping; measurement and modelling

A novel laboratory microcosm test was developed to measure the diffusion of native PAHs and PCBs from sediments in the presence and absence of a capping layer. Diffusive flux of 15 PAHs and 7 PCBs from uncapped sediment from Oslo harbour was 3.8+/-0.9 microg m(-2)d(-1) and 0.010+/-0.003 microg m(-2)d(-1), respectively. The flux from sediments capped with 1cm mineral cap (crushed limestone or crushed gneiss (0-2mm)), observed during the first 410 d, was 3.5-7.3% of the flux from uncapped sediments. By measuring freely dissolved pore water concentrations of 10 PAHs the flux in the microcosm was modelled with steady state and transient diffusion models. The measured flux from uncapped sediment was 27-290% of modelled steady state flux. Good agreement was also found between the measured flux of pyrene from capped sediment and the flux modelled with the transient model when fitting only with the distribution coefficients for pyrene between the cap material and water (Kd_pyr). Fitted Kd_pyr, (210 and 23 l kg(-1) for limestone and gneiss, respectively) was in the same order of magnitude as K(d) calculated from organic carbon content in the cap materials (68 and 14 l kg(-1) respectively). Calculation of the efficiency of a hypothetical cap with 10 cm diffusion path shows that the increased diffusion path length alone can yield a flux reduction >99% through a strong increase in the stagnant diffusive boundary layer from <1 to 100mm.     

Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) distributions in the Bay of Marmara sea: Izmit Bay

In 1999, the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), the total PAH and polychlorinated biphenyls (PCBs) were measured in sea water, sediment and mussels collected along the coast of Izmit Bay, the most important bay of the Marmara Sea. The total-PAH concentrations, measured by Spectrofluorometry were in the range of 1.16-13.68 microg/l in sea water, in the range of 30.0 1670.0 microg/g dry weight in sediments and in the range from 5.67 to 14.81 microg/g wet weight in edible part of mussel. HPLC revealed Phenanthrene (three rings), chrysene (four rings) and benz[a]antracene (five rings) to be the dominant PAHs in sea water, while 16 different PAHs compounds were observed and measured in mussel samples. The most pollution occured at Dogu Kanali and Dil Deresi where were the main rivers containing wastes fall into the the Izmit Bay. Although the maximum mono-ortho PCB concentrations in sea water were measured in the Dil Deresi River (26.33 ng/l) and the Solventa? (22.19 ng/l) stations, maximum PCB concentrations in mussels were measured in the SEKA (28.11 microg/kg) and the Dil Deresi River (25.68 microg/kg). The dominant congeners of PCBs were from tetra to hexachlorobiphenyls. The toxicity equivalent values were very low in sea water and mussels.     

Distribution,source, and ecological risk assessment of PAHs among size and density fractions in contaminated sediments from the Yellow River of Henan section

This study investigated particle size and density distributions of polycyclic aromatic hydrocarbons (PAHs) in two surface sediments (JZ and KF), collected from the Yellow River of Henan section, China. The concentrations of Σ₁₅PAHs ranged from 35.6 to 45862?ng g^?1 dry wt, which were greatly elevated in coarse particles and low-density fractions. The Σ₁₅PAHs concentrations in low-density fractions were 533 (JZ) and 996 (KF) times higher than those in the corresponding high-density fractions. However, due to relatively less quantities of low-density fractions (0.27–2.33%), most of the PAHs were contributed by the high-density components. For both sediments, the influence factors of PAHs source in the environment were very complex, more so than the level of TOC and BC content. JZ sediment was dominated by 4-ring to 6-ring PAHs (61.5–75.1%), while, 2-ring to 3-ring PAHs were abundant in KF samples (39.8–72.6%). Ratios of specific PAHs reflected PAHs among the size- and density-fraction of each sediment may be contaminated by mixed of pyrolytic and petrogenic origin. Additionally, ecological risk assessment of PAHs suggested that total toxic equivalent values of PAHs in the low-density fractions were much higher than those of the corresponding high-density fractions in the studied area.     

Impacts of urbanization on surface sediment quality: evidence from polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) contaminations in the Grand Canal of China

Introduction

Organic pollutants, especially synthetic organic compounds, can indicate paces of anthropogenic activities. Effects of urbanization on polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) distributions in surface sediment were conducted in urban sections of the Grand Canal, China, consisting of a four-level urbanization gradient.

Materials and methods

The four-level urbanization gradients include three countryside towns, two small-size cities, three medium-size cities, and a large-size city. Diagnostic ratio analysis and factor analysis?Cmultiple linear regression model were used for source apportionment of PAHs. Sediment quality guidelines (SQGs) of USA and Canada were employed to assess ecological risks of PAHs and PCBs in surface sediments of the Canal.

Results and discussion

Ranges of PAH and PCB concentrations in surface sediments were 0.66?C22?mg/kg and 0.5?C93???g/kg, respectively. Coal-related sources were primary PAH sources and followed by vehicular emission. Total concentration, composition, and source apportionment of PAHs exhibited urbanization gradient effects. Total PCB concentrations increased with the urbanization gradient, while total PAHs concentration in surface sediments presented an inverted U Kuznets curve with the urbanization gradient. Elevated concentrations of both PAHs and PCBs ranged at effect range low levels or interim SQG, assessed by USA and Canadian SQGs.

Conclusions

PAHs and PCBs in surface sediments of the Grand Canal showed urbanization gradient effects and low ecological risks.     

Ecotoxicological effects of sediments from Mar Piccolo,South Italy: toxicity testing with organisms from different trophic levels

The Mar Piccolo of Taranto (Ionian Sea, Southern Italy) is a semi-enclosed and strongly polluted basin. For decades, it has been subjected to different anthropogenic impacts. These stressors caused severe sediments contamination with high concentration of different pollutants (PAHs, PCB, heavy metals). In order to assess the current status of sediments contamination, an ecotoxicological investigation combined with chemical analysis (heavy metals, PAH, and PCB) has been performed. In order to derive ecologically relevant conclusions, a multiorganisms and multiend-points approach has been applied, exposing organisms from different trophic levels to elutriate and whole sediment. The battery of bioassays consists of a microalgal growth inhibition test (Dunaliella tertiolecta), acute and sublethal assays (end-points: mortality, immobilization and swimming speed alteration) on crustaceans larvae and juveniles, and rotifers (Amphibalanus amphitrite, Artemia salina, Corophium insidiosum and Brachionus plicatilis), and embryotoxicity test on echinoderms (Paracentrotus lividus). Considering the high levels of sediment contamination highlighted from chemical analysis, an unexpected very low toxic effect was observed, even considering the sublethal end-point (larval swimming speed alteration). The results of this study suggest a very complex contaminants dynamic in the Mar Piccolo sediments that, despite a strong level of contamination, seems to not affect in a proportional manner the biological compartment.     

Records of polychlorinated biphenyls (PCBs) in sediments of four remote Chilean Andean Lakes

Sediment cores from four Chilean lakes along the Andes Chain (Chungará, Laja, Castor and Venus) were analysed in order to investigate PCB concentrations and distributions in sediment samples. Sediment cores were analysed for PCBs using gas chromatography (GC-ECD/MS) and radioisotopically dated using 210Pb. Organic carbon content (OC) and 210Pb fluxes were also measured. Results showed that sediment PCB concentrations (ngg(-1) d.w.) at Lake Chungará (1.2 +/- 1) in northern Chile, Laja (5 +/- 4) in central, and in Lake Castor (3.5 +/- 4) in southern Chile (the eastern side of the Andes Mountain) were lower than sediments collected from Lake Venus (64 +/- 30) located in southern Chile (the western side) which contained 15-fold higher concentrations of PCBs. The percentage (%) of organic carbon was variable and showed a high range of values in the sediment fluctuating from 2% (Lake Laja) to 22% (Lake Chungará). Analysis of 210Pb fluxes, presented a decrease trend following Lake Laja>Castor>Chungará with a positive correlation with rainfall at each site. Sedimentation rates in Lake Castor (1846 gm(-2)yr(-1)) were higher than at Chungará (748 gm(-2)yr(-1)) and Lake Laja (508 gm(-2)yr(-1)). Focusing factor (FF) is used as a tool to elucidate PCB input in the aquatic ecosystem. FF were lower (<1) for the shallower lakes (Lakes Chungará and Castor). This study provides background levels of PCBs at remote lakes in Chile. Differences in geographical characteristics (orographic effect) might play an important role in the arrival of PCBs, particularly into the southern lakes. PCB fluxes indicated deposition of PCBs in recent sediments is higher than in previous years with peaks of PCB between 1991 and 1998. The continuing increase of PCB inputs in remote Chilean lakes, could be associated with long range atmospheric transport (LRAT).     

Flux estimates and sedimentation of polychlorinated naphthalenes in the northern part of the Baltic Sea

The concentrations and fluxes of polychlorinated naphthalenes (PCNs) were measured in surface sediments, and settling particulate matter collected in sediment traps, at two coastal and two offshore sampling stations in the Gulf of Bothnia, northern Baltic Sea, Sweden. The PCN concentrations (of tetra- to hepta-chloro congeners) in the surface sediments ranged from 0.27 to 2.8 ng/g dry weight and were of the same order of magnitude as background concentrations reported previously in Europe. The PCN fluxes in the southern basin (0.93 and 0.86 microg/m2/year) of the Gulf of Bothnia were higher than those in the northern basin (0.58 and 0.49 microg/m2/year); they were also higher near the coast than in the open sea. These PCN fluxes are similar to the pre-industrial levels determined from lake sediments in northwest England. The PCN homologue distribution changed from a relatively even distribution in samples collected near the coast, to TeCNs dominating in the samples from the open sea. This indicates that higher chlorinated PCNs are deposited and retained in sediments to a higher degree near the coast. The total annual deposition of PCNs in sediments in the Gulf of Bothnia was estimated to be 91 kg/year.     

Ecosystem functioning approach applied to a large contaminated coastal site: the study case of the Mar Piccolo of Taranto (Ionian Sea)

Knowledge on ecosystem functioning can largely contribute to promote ecosystem-based management and its application. The Mar Piccolo of Taranto is a densely populated area at a high risk of environmental crisis. Here, planktonic primary production (PP) and heterotrophic prokaryotic production (HPP) were measured as proxies of functioning in three sampling sites located in two inlets at different levels of industrial contamination, during three sampling surveys (June 2013, February and April 2014). To have a better overall view and provide some insights into the benthic-pelagic coupling, we integrated PP and HPP in the water column with those in the sediments and then discussed this with the origin of the organic matter pools based on analysis of stable isotopes. Heavy metals and polychlorobiphenyls (PCBs) were also analysed in the surface (1 cm) sediment layer and related to the overall ecosystem functioning. Multidimensional scaling (MDS) analysis, based on the main data, clearly separated the second inlet from the first one, more severely impacted by anthropogenic activities. The stable isotope mixing model suggested the prevalent terrestrial/riverine origin of the particulate organic matter pools (mean 45.5 %) in all sampling periods, whereas phytoplankton contributed up to 29 % in February. Planktonic PP and HPP rates followed the same pattern over the entire study period and seemed to respond to phytoplankton dynamics confirming this community as the main driver for the C cycling in the water column. On the contrary, benthic PP rates were almost negligible while HPP rates were lower or comparable to those in the water column indicating that although the Mar Piccolo is very shallow, the water column is much more productive than the surface sediments. The sediment resuspension is likely responsible for a pulsed input of contaminants into the water column. However, their interference with the proper functioning of the pelagic ecosystem seems to be limited to the bottom layers.     

SITE Demonstration of the Basic Extractive Sludge Treatment Process

The Superfund Innovative Technology Evaluation (SITE) Program, in cooperation with EPA Region 5, the Great Lakes National Program Office (GLNPO), and the U.S. Army Corps of Engineers (COE) planned and executed a pilot-scale evaluation of the Basic Extractive Sludge Treatment (B.E.S.T.®) process on sediment samples obtained from the Grand Calumet River in Gary, Indiana. Two separate sampling locations were selected based upon previous data. One location had sediments with total polychlorinated biphenyl (PCB) concentrations averaging 10 mg/kg, and total polynuclear aromatic hydrocarbon (PAH) concentrations averaging 520 mg/kg. The other location had sediments with average total PCB and PAH concentrations of 427 mg/kg and 72,000 mg/kg, respectively. The sediment samples were segregated by location, then screened, homogenized, and stored prior to treatment. A total of ten batches of sediments were treated (five for each sample location).

Results showed that of the samples which had low original contaminants concentrations, 96 percent of the PAHs and >99 percent of the PCBs were removed following seven sequential extractions. Treated samples which had high original contaminant concentrations were found to have removal efficiencies of >99 percentfor both PAHs and PCBs. Costs for applying this technology were estimated at $94.19/ton (assuming the system is on-line 80 percent of the time) excluding fixed costs associated with system mobilization/ demobilization and setup, and profit.     

The chemical response of particle-associated contaminants in aquatic sediments to urbanization in New England, U.S.A

Relations between urbanization and particle-associated contaminants in New England were evaluated using a combination of samples from sediment cores, streambed sediments, and suspended stream sediments. Concentrations of PAHs, PCBs, DDT, and seven trace metals (Cd, Cr, Cu, Hg, Ni, Pb, Zn) were correlated strongly with urbanization, with the strongest relations to percentage commercial, industrial, and transportation (CIT) land use. Average PAH and metal concentrations in the most urbanized watersheds were approximately 30 and 6 times the reference concentrations, respectively, in remote, undeveloped watersheds. One-quarter to one-half of sampling sites had concentrations of PAHs, Cu, Pb, or Zn above the probable effects concentration, a set of sediment quality guidelines for adverse effects to aquatic biota, and sediments were predicted to be toxic, on average, when CIT land use exceeded about 10%. Trends in metals in cores from urban watersheds were dominantly downward, whereas trends in PAHs in a suburban watershed were upward. A regional atmospheric-fallout gradient was indicated by as much as order-of-magnitude-greater concentrations and accumulation rates of contaminants in cores from an undeveloped reference lake in Boston compared to those from remote reference watersheds. Contaminant accumulation rates in the lakes with urbanization in their watersheds, however, were 1-3 orders of magnitude greater than those of reference lakes, which indicate the dominance of local sources and fluvial transport of contaminants to urban lakes. These analyses demonstrate the magnitude of urban contamination of aquatic systems and air sheds, and suggest that, despite reductions in contaminant emissions in urban settings, streams and lakes will decline in quality as urbanization of their watersheds takes place.