Polychlorinated Biphenyls In Sediments Research Articles

Historically linked residues profile of OCPs and PCBs in surface sediments of typical urban river networks, Shanghai: Ecotoxicological state and sources

Residues, potential sources and ecotoxicological effects of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were analyzed in typical urban river networks of Shanghai. In total, 47 surface sediments were collected in each of the sampling seasons (summer and winter). Laboratory analysis by GC-ECD showed that OCPs and PCBs concentrations were in medium levels compared to other national and international areas. As for OCP compounds, HCHs and DDTs were two dominant pollutants, with ∑HCHs concentrations ranging from 1.74 to 28.78 ng/g and ∑DDTs concentrations ranging from 0.88 to 25.45 ng/g. For individual HCHs, β-HCH was the most dominant HCH compound, with a mean value of 5.06 ng/g, followed by α-HCH (3.50 ng/g) in winter. A similar case of HCHs was also found in the summer season. Concentrations of ∑18PCBs varied from 6.67 to 37.10 ng/g in winter and from 10.63 to 45.55 ng/g in summer. Individual PCB 28, 101, 118 and 123 were dominant among all congeners, with averages of 3.16, 1.55, 2.47 and 2.37 ng/g in winter, 3.11, 2.34, 4.92 and 4.41 ng/g in summer, respectively. ∑20OCPs (the sum of twenty OCPs) concentrations in cultivated land areas were more abundant than that in artificial surface areas, indicating an abundance of pesticides and fertilizers in cultivated lands. Analysis of possible sources indicated that both industrial and agricultural residues contributed to higher HCHs and DDTs concentrations, which mainly originated from weathered pesticides with aerobic transformation processes. For PCB compounds, a significant seasonal variation, atmospheric precipitation, and surface runoff were the major factors for fluctuated PCBs concentrations. Ecotoxicological assessment based on established sediment quality guidelines (SQGs) showed that DDT compounds have a potential threat to the aquatic environment of our study area.

The interactive effect of the season and estuary position on the concentration of persistent organic pollutants in water and sediment from the Cua Dai estuary in Vietnam.

The current study was conducted in the Cua Dai estuary, Vietnam, (1) to assess the status of persistent organic pollutants (POPs) and (2) to examine the interactive effect of season and estuary position on the concentration of the pollutants in surface water and sediment. Fifty-two water and sediment samples were taken in the dry and rainy seasons from inner- and outer-estuary positions to analyze for six POPs, including hexachlorocyclohexane isomers (HCHs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), heptachlor, aldrin, dieldrin, and polychlorinated biphenyl (PCBs). The averaged concentrations of the respective POPs in water samples were 0.07, 0.1, 0.01, 0.03, 0.001, and 0.2 μg L-1 and in sediment samples were 2.6, 3.1, 0.9, 0.2, 0.2, and 121 μg kg-1. Of the six POPs examined, the concentration of DDTs in sediment samples and PCBs in water samples was significantly affected by the interactive effect of the two examined factors. The concentrations of HCHs, DDTs, heptachlor, and aldrin in water samples and of HCHs in sediment samples were significantly higher in the rainy season than in the dry season. Sediment samples collected from the inner position had a significantly higher concentration of HCHs and PCBs than in the outer position. Some mechanisms possibly influenced the varying POP concentration could include (1) greater riverine discharge in the rainy season and (2) the sea dilution effect in the outer position. Therefore, the concentration of the individual examined POPs in water and sediment in the Cua Dai estuary significantly depended on either the season, estuary position, or their combination.

Climate change impacts on polychlorinated biphenyls (PCBs) deposition in a shallow lake, China

The deposition of PCBs in lake sediments was affected by climate change and anthropogenic activities. To better understand the mechanism, GAMs models were performed to investigate the relationship between sedimentary PCBs and the two influential factors. The results showed the average contribution value of the sum of temperature and evaporation to PCBs (7.1%) was larger than that of the sum of aquatic TP and GDP (17.9%), indicating human activity is a major factor compared to climate change. The increasing total phosphorus and Gross Domestic Product in Lake Chaohu with the development of urbanization and industrialization promoted the deposition of PCBs in Lake Chaohu sediments before the consideration of environment management. The fitted relationship between sedimentary PCBs concentrations and Temperature was linear for Lake Chaohu, suggesting that increasing temperature enhanced the volatilization from primary and secondary sources and reduced the fugacity capacity of PCBs in water and sediments. The sedimentary PCBs concentrations increased with decreasing evaporation. In consequence, the interactive effect of climate change and anthropogenic activities must be addressed from a scientific perspective for future regulatory actions.

Colonization and growth of dehalorespiring biofilms on carbonaceous sorptive amendments

Removal of polychlorinated biphenyls (PCBs) from contaminated sediments is a priority due to accumulation in the food chain. Recent success with reduction of PCB bioavailability due to adsorption onto activated carbon led to the recognition of in situ treatment as a remediation approach. In this study, reduced bioavailability and subsequent break-down of PCBs in dehalorespiring biofilms was investigated using Dehalobium chlorocoercia DF1. DF1 formed a patchy biofilm ranging in thickness from 3.9 to 6.7 µm (average 4.6 ± 0.87 µm), while the biofilm coverage varied from 5.5% (sand) to 20.2% (activated carbon), indicating a preference for sorptive materials. Quantification of DF1 biofilm bacteria showed 1.2–15.3 × 109 bacteria per gram of material. After 22 days, coal activated carbon, bone biochar, polyoxymethylene, and sand microcosms had dechlorinated 73%, 93%, 100%, and 83%, respectively. These results show that a biofilm-based inoculum for bioaugmentation of PCBs in sediment can be an efficient approach.

Effect of aging on bioaccessibility of DDTs and PCBs in marine sediment

Hydrophobic legacy contaminants like dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCBs) were banned almost half a century ago. While their residues still remain in many environmental compartments, they have undergone extensive aging and likely have lower bioaccessibility (the available fraction) compared to fresh residues. However, risk assessment relies heavily on the use of total chemical concentration, rather than accounting for age-diminished bioaccessibility, likely leading to overestimated risks. In this study, we used 24 h Tenax desorption to measure the potential bioaccessibility of DDTs and PCBs in two sediment cores taken from the Palos Verdes Shelf Superfund site in the Pacific Ocean. The total concentrations of DDTs and PCBs from the core located at the sewage outfall (8C) were as high as 41,000–15,700 μg/kg (dry weight, dw) and 530-2600 μg/kg dw, respectively, while those from a location 7 km northeast of the outfall (3C) were 2–3 orders of magnitude lower. Bioaccessibility estimated by 24-h Tenax-aided desorption (F24h) decreased in the order of DDD > DDE > DDT for DDT derivatives, and PCB 52 > PCB 70 > PCB 153 for PCB congeners, showing a negative correlation with their log Kow. Due to the extensive aging, F24h values were <20% of the total chemical concentration for most contaminants and <5% for DDT, DDE and PCB 153, suggesting that aging greatly diminished their bioavailability. However, a quantitative relationship between F24h and sediment age along the vertical profile was not found, likely because the contaminant residues had undergone aging before their offsite transport and deposition onto the ocean floor. As the use of man-made chemicals such as DDT and PCBs was discontinued in the U.S. many decades ago, the reduction in their bioavailability due to aging may be universal and should be taken into consideration to avoid overly conservative risk predictions or unnecessary mitigation interventions.

Occurrence, sources and ecotoxicological risks of polychlorinated biphenyls (PCBs) in sediment cores from urban, rural and reclamation-affected rivers of the Pearl River Delta, China

Sediment cores were collected to a depth of 40 cm (50 cm for urban river sediments) in the Pearl River Delta of China from rural river sediments and river sediments undergoing the process of urbanization and reclamation. Polychlorinated biphenyls (PCBs) in sediment cores were determined to evaluate their levels, distribution, possible sources and potential risks aimed at providing effective information of management practices for local governments. Our results showed that the total concentrations of PCBs (∑16PCBs) in urban, rural and reclamation-affected river sediments ranged from 16.15 to 477.85 μg kg−1 (dry weight), with mean values of 121.94, 150.49 and 124.20 μg kg−1 (dry weight), respectively. The most abundant PCB congeners among the study area were light PCBs. Generally, PCBs showed a decreasing trend with depth along sediment cores at most sampling sites. Source analysis indicated that PCBs in the three types of river sediments mainly originated from Aroclor 1242, 1248, 1254 and 1016. Risks evaluation based on sediment quality guideline quotient (SQGQ) showed PCBs at most sampling sites would cause no or moderate adverse biological effects on benthic organisms except surface sediments of U4 and R5 (high adverse biological effects). However, threshold effects level (TEL) is ignored when calculating SQGQ, which might underestimate the risks of PCBs. Thus, a new SQGQ (NSQGQ) taken TEL into consideration was established. Results showed that NSQGQ could evaluate ecotoxicological risks of PCBs better. Redundancy analysis (RDA) showed that PCBs in sediments were positively correlated with sand content and microbial biomass carbon (MBC) (p < 0.05).

Bioaccumulation and cycling of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in three mangrove reserves of south China

Total 22 organochlorine pesticides (OCPs) compounds and 31 polychlorinated biphenyls (PCBs) congeners in mangrove sediments and tissues (leaf, branch, root and fruit) of nine species from three Mangrove Reserves of China were studied. The mean concentrations of total DDTs, HCHs, OCPs and PCBs in sediments were 2.84, 0.06, 3.84 and 0.17 ng g−1 dw, while those in tissues were 1.85, 0.22, 9.43 and 1.61 ng g−1 dw, respectively. The elevated OCPs and PCBs levels in mangrove leaves may be caused by atmospheric sedimentation. The biota sediment accumulation factor (BSAF) values of both OCPs (mean: 3.4) and PCBs (mean: 9.9) are generally larger than one, implying mangroves' bioaccumulation and their ability to intercept pollutants. The BSAFs of PCBs in mangrove tissues were negatively correlated with the PCB congener's octanol-water partition coefficients (KOW, R = 0.58, n = 31, p < 0.001), suggesting that lower chlorinated CB congeners are more bioaccumulative in mangroves. In order to better understanding the fate of these organochlorine compounds, the cycling (including the standing accumulation, the annual absorption, the annual net retention, the annual return, and the turnover period) of OCPs and PCBs in the Mangrove Reserves were estimated, and the results indicated that mangroves are playing important roles in retaining OCPs and PCBs.

Quantitative analyses of selected polychlorinated biphenyl (PCB) congeners in water, soil, and sediment during winter and spring seasons from Msunduzi River, South Africa.

The lack of information and the need for knowledge on the organic pollutants within the area of KwaZulu-Natal together with the global problem of water supply have prompted our investigation into the analyses of eight polychlorinated biphenyl (PCB) congeners in the Msunduzi River of KwaZulu-Natal, South Africa. Soil, sediment, and water samples were collected at ten different sites along the river during winter and spring seasons. Soil and sediment samples were extracted using ultra sonication with dichloromethane while water samples were liquid-liquid extracted using dichloromethane. All sample extracts were cleaned-up using a multi-layer silica gel column and analyzed with gas chromatography-mass spectrometry. Quality assurance measures were also determined. The percentage recoveries for water were 53-128 for all the PCBs analyzed, while sediment recoveries ranged between 69 and 105%. The highest total concentrations of the PCBs in sediment were 214.21-610.45ng/g dw at the Du Toit sampling site and 30.86-444.43ng/g dw basis at the wastewater treatment inlet for winter and spring, respectively. Soil PCB concentrations were 76.53-397.75ng/g dw at the Msunduzi Town sampling site and 20.84-443.49ng/g (dry weight) at the Du Toit sampling site for winter and spring, respectively. In addition, high PCB concentrations were found in effluent of the wastewater treatment inlet compared to other sampling sites, which ranged between 0.68-22.37 and 2.53-35.69ng/mL for winter and spring seasons, respectively. In all the sampling sites selected for this study, Du Toit afforded the highest PCB concentration levels and the lowest was after chlorination at the Darvill wastewater treatment plant. The results presented are new and it is the first study of organic pollutants such as PCBs that has been carried out on this river.

Effects of Ferric Oxyhydroxide on Anaerobic Microbial Dechlorination of Polychlorinated Biphenyls in Hudson and Grasse River Sediment Microcosms: Dechlorination Extent, Preferences, Ortho Removal, and Its Enhancement.

Microbial reductive dechlorination of polychlorinated biphenyls (PCBs) has been observed in many PCB-impacted sediments. However, this biodegradation is relatively site-specific and can be affected by PCB compositions and sediment geochemical conditions. To better understand the influence of a common competing electron acceptor, ferric oxyhydroxide (FeOOH), on dechlorination, two sediments (Hudson River and Grasse River sediments), and two PCB mixtures (PCB 5/12, 64/71, 105/114, and 149/153/170 in Mixture 1 and PCB 5/12, 64/71, 82/97/99, 144/170 in Mixture 2) were used for this microcosm study. The addition of 40 mmole/kg FeOOH completely inhibited PCB dechlorination in the Hudson sediment, but only moderately inhibited PCB dechlorination in the Grasse sediment with a 3-week longer lag time. The inhibitory effect in the Grasse sediment was mainly due to the loss of unflanked para dechlorination activity. Fe(II) analysis showed that dechlorination started prior to the consumption of Fe(III), which indicates PCB reduction and Fe(III) reduction were able to take place concurrently. Dehalococcoides 16S rRNA genes increased with the commencement of dechlorination in the Grasse sediment, but not in the completely inhibited Hudson sediment. Rare ortho dechlorination pathways were identified in FeOOH-amended Grasse sediment microcosms, dominated by transformations of PCB 25(24-3-CB) to PCB 13(3-4-CB) and PCB 28(24-4-CB) to PCB 15(4-4-CB). The addition of carbon sources (acetate or a fatty acid mixture with acetate, propionate, and butyrate) after 27 weeks of incubation reinitiated dechlorination in FeOOH-amended Hudson sediment microcosms. Also, the addition of carbon sources greatly enhanced ortho dechlorination in FeOOH-amended Grasse microcosms, indicating the utilization of acetate and/or the fatty acid mixture for ortho dechlorination-related microorganisms. A dechlorination pathway analysis approach revealed that para-flanked meta dechlorination was primarily preferred followed by ortho-/double-flanked meta dechlorination and single-/double-flanked para dechlorination in the Grasse sediment.

Efficacy of carbon-based materials for remediating polychlorinated biphenyls (PCBs) in sediment

Polychlorinated biphenyls (PCBs) are persistent hydrophobic compounds that are present widely in the environment. Due to poorly maintained hazardous waste sites, electrical equipment leakage, and illegal disposal, PCBs were deposited in sediments present in bays and estuaries. PCBs continuously partition into the overlying water posing a long-term exposure risk to the environment and human health. This study demonstrates the efficacy of carbon-based materials in reducing the partitioning of PCBs from sediment to the water column. Both existing carbon-based materials [activated carbon (AC), black carbon (BC)] and emerging nanomaterials [graphene (GE), graphene oxide (GO), carbon nanotube (CNT)] were tested to determine their efficacy to bind PCBs in sediment. The comparison between the sorbents was accomplished by examining their distribution coefficient (Ks). The magnitude of Ks provides an idea about the bioavailable fraction of PCBs in the system; the higher the Ks, the greater the strength of sorption by the sorbent and therefore, the lower the PCB bioavailability. Results from the sorption experiment indicated that CNT performed the best overall followed by AC, BC, GO and GE. Results indicated that the Ks value for CNT was 1.16, 1.15, 1.13 and 1.04 log units greater than GE, GO, BC, and AC.

Assessment of Polychlorinated Biphenyls (PCBs) in water, sediments and biota from e-waste dumpsites in Lagos and Osun States, South-West, Nigeria

The levels of PCBs in sediments, water, leachate and aquatic fauna ( Tilapia guineensis , Callinectes amnicola and Cardiosoma armatum ) found in and around e-waste dumpsites in Lagos and Osun States, South-West, Nigeria were analyzed using Gas Chromatography Electron Capture Detector (GC ECD) Agilent 7820A. All the 28 PCBs congeners studied were detected with the Σhexa-PCBs dominating in Lagos (21%) while the Σtetra-PCBs (24%) enriched the samples from Osun State. The concentrations of Σ- PCBs in decreasing order were Lagos: sediment ˃ fish gill ˃ fish muscles ˃ water ˃ crab ˃ leachate and Osun: fish gill ˃ fish muscle ˃ sediment ˃ crab ˃ water ˃ leachate. The concentrations of total indicator PCBs ( Σ7PCBs) in the sediment from Lagos (4.19 μg/kg) and Osun (8.58 μg/kg) exceeded the Canadian Sediment Quality standard threshold effect level (CSQ TEL) (0.03 μg/kg) and the National Oceanic Atmospheric Administration threshold effect level (NOAA TEL) for fresh and marine sediments.. The calculated toxic equivalent quotient (TEQ) for fish from Lagos and Osun (3.7 and 4.4) respectively further suggests a likely occurrence of adverse effects to humans who consume the fish. This study reveals the high health and ecological risks associated with e waste pollution in the aquatic environment. Keywords: e-waste, polychlorinated Biphenyls, aquatic environment, leachate

Matrix effects on organic pollutants analysis in marine sediment

Interference from the matrix sample can influence of the accurate analytical method. Accelerated Solvent Extraction and their purification methods were tried to separate the organic micropollutants respectively in marine sediment. Those matrix were as organic pollutants evaluation in marine environment. Polychlorinated Biphenyls (PCBs) and Organochlorine pesticides (OCPs) are two examples organic pollutant in environment which are carcinogenic and mutagenic. Marine sediments are important matrices of information regarding the human activities in coastal areas as well as the fate and behavior of organic pollutants, which are persistent in long-term. This research purpose to evaluate the matrice effect and the recovery from marine sediment spiking with several standar solution and deuterium of molecular target from organic pollutants in not polluted sample of sediment. Matrice samples was tested from indicate in unpolluted location. The methods were evaluated with standard calibration curve (linearity < 0.999, LOQ various ranged 0.5-1000 pg.μL-1 and LOD > LOQ). Recovery (YE) relative, Matrice Effect (ME) relative correction with deuteriated standar were evaluated the interference the matrix. Interference effect for OCPs compounds were higher than PCBs in marine sediment.

PAHs, OCPs and PCBs in sediments from three catchments in Durban, South Africa

Polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were analysed from sediment samples collected in 2012 from rivers, surface runoff canals and estuaries in three highly urbanised catchments in durban, KwaZulu-Natal, South Africa. PAHs were ubiquitous, at concentrations between 36–6 800 ng g−1 dry mass (dm). Congener ratio diagnosis suggests the PAHs were derived predominantly from pyrogenic sources. Four OCPs and/or their metabolites were detected at varying frequencies and concentrations. Of these, dichlorodiphenyltrichloroethane (ddT) and metabolites were most frequently detected and were at a high concentration in sediment in some systems. Toxaphene was detected at a high concentration at some sites. The total PCB concentration varied widely, from below the method detection limit to 110 ng g−1 (dm). Based on the comparison of chemical concentrations to international sediment quality guidelines, PAH, OCP and PCB concentrations in most sediment samples posed a low risk to sediment-dwelling organisms. However, in some instances the risk was moderate or high. It is recommended that these compounds be monitored more frequently and comprehensively in aquatic ecosystems to better understand the ecological and human health implications.

Application of probabilistic risk assessment: Evaluating remedial alternatives at the Portland Harbor Superfund Site, Portland, Oregon, USA.

A probabilistic risk assessment (PRA) was performed to evaluate the range of potential baseline and postremedy health risks to fish consumers at the Portland Harbor Superfund Site (the "Site"). The analysis focused on risks of consuming fish resident to the Site containing polychlorinated biphenyls (PCBs), given that this exposure scenario and contaminant are the primary basis for US Environmental Protection Agency's (USEPA's) selected remedy per the January 2017 Record of Decision (ROD). The PRA used probability distributions fit to the same data sets used in the deterministic baseline human health risk assessment (BHHRA) as well as recent sediment and fish tissue data to evaluate the range and likelihood of current baseline cancer risks and noncancer hazards for anglers. Areas of elevated PCBs in sediment were identified on the basis of a geospatial evaluation of the surface sediment data, and the ranges of risks and hazards associated with pre- and postremedy conditions were calculated. The analysis showed that less active remediation (targeted to areas with the highest concentrations) compared to the remedial alternative selected by USEPA in the ROD can achieve USEPA's interim risk management benchmarks (cancer risk of 10-4 and noncancer hazard index [HI] of 10) immediately postremediation for the vast majority of subsistence anglers that consume smallmouth bass (SMB) fillet tissue. In addition, the same targeted remedy achieves USEPA's long-term benchmarks (10-5 and HI of 1) for the majority of recreational anglers. Additional sediment remediation would result in negligible additional risk reduction due to the influence of background. The PRA approach applied here provides a simple but adaptive framework for analysis of risks and remedial options focused on variability in exposures. It can be updated and refined with new data to evaluate and reduce uncertainty, improve understanding of the Site and target populations, and foster informed remedial decision making. Integr Environ Assess Manag 2018;14:63-78. © 2017 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

PAH, PCB, TPH and mercury in surface sediments of the Delaware River Estuary and Delmarva Peninsula, USA

Surface sediment concentrations of polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB), total petroleum hydrocarbons (TPH) and mercury, were compared from two areas with contrasting land use history, the industrial Delaware Estuary and the rural Delmarva Peninsula (USA). TPH in the Delaware (38–616mg/kg) and saturate/aromatic fractions suggested petroleum/industrial sources compared to biogenic sources in the Delmarva coastal control (<34–159mg/kg). Within the Delaware the ∑PAH18 ranged from 3749 to 22,324μg/kg with isomeric ratios indicative of petroleum combustion source/s, conversely, those in the Delmarva (5–2139μg/kg) also yielded relatively higher perylene that were consistent with natural background levels derived from vegetation/coal combustion source/s. ∑PCB(tri-hepta) concentrations in the Delmarva (0.6–6.5μg/kg) were less than the threshold effect concentration (TEC), whereas the Delaware had received much higher PCB loading (18.1–136.8μg/kg) as evidenced by a significantly higher amounts in some samples (>TEC).

Characteristics, distribution and sources of polychlorinated biphenyls (PCBs) in coastal sediments from the heavily industrialized area of Asalouyeh, Iran.

In this research, the levels of polychlorinated biphenyls (PCBs) were investigated in the marine sediments of Asaluyeh harbor, in the Persian Gulf. The samples were taken from industrial, semi-industrial and urban regions. The mean concentration levels of total (Σ) 18 detected PCBs were 514.32, 144.67 and 31.6 pg/g dw for the industrial, semi-industrial and urban sampling stations, respectively. Based on a multivariate statistical analysis, it was found that high contamination levels of PCBs in sediments collected along the Persian Gulf were associated with releases from local industries. Total organic carbon (TOC) content was significantly and positively correlated with the concentrations of PCB congeners. World Health Organization toxic equivalents (TEQs) for PCBs ranged from 0.04 to 2.66 pg TEQ/g dry weight (dw) in the coastal sediments. The TEQ values in this study were higher than many reported worldwide in the literature for sediments. This suggests that there are high levels of contamination in the area due to industrial and other human activities.

Spatial distribution of polycyclic aromatic hydrocarbon and polychlorinated biphenyl sources in the Nakdong River Estuary, South Korea

ABSTRACTOur research team investigated the elemental composition and the presence of various toxic organic compounds, such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), in estuary surface sediments to trace the spatial distribution of the sources of pollution deposited in Nakdong River, Busan, South Korea. The spatial patterns of elemental composition and toxic organic compounds were determined from the measurements of total organic carbon (TOC), total nitrogen, total sulfur, PAHs, and PCBs. The sediments had TOC contents of between 0.02 and 1.80 wt% (avg. 0.34 wt%), depending on the amount of clay-sized particles. The concentrations of PAHs and PCBs (10.8–167.7 ng g−1 dry wt and 197.0–754.0 pg g−1 dry wt, respectively) in surface sediments revealed different spatial patterns for these compounds, suggesting that they partially originated from the combustion of fossil fuels and from the use of commercial PCB products at adjacent industrial complexes. Although these concentrations were far below the Sediment Quality Guideline (SQG) of the National Oceanic and Atmospheric Administration (NOAA), the sediments at one site contained PCBs at concentrations close to the response level (754.0 pg g−1 dry wt), and were dominated by low-molecular-weight PAHs. The PAHs and PCBs in Nakdong River Estuary sediments were likely to have originated from the combustion of fossil fuels and biomass at the adjacent industrial complexes. The primarily analyzed results determined that PAHs originated from the combustion of fossil fuels and biomass, and overall concentrations were related to the contributions of individual PAHs in most sediment samples. Based on the SQG of the NOAA, our results indicate that the anthropogenic activity should be considered on the future-sustainable management of this estuary system.

Distribution of organic contamination of sediments from Ichkeul Lake and Bizerte Lagoon, Tunisia

Analyses of organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and butyl tins (BuSn) were conducted on sediments from Ichkeul Lake-Bizerte Lagoon watershed (Tunisia). A total of 59 compounds (16 PAHs, 12 PCBs, 22 OCPs and 9 BuSn) were measured in 40 surface sediment samples collected during two campaigns. High concentrations of total PAHs were identified in the lagoon ranging from 122 to 19600ng·g−1. Several OCPs, including endrin, dieldrin, and lindane (Hexachlorocyclohexane or HCH or BHC) were found in high concentrations in Ichkeul Lake, ranging from 28 to 2012ngg−1. PAHs and OCPs varied seasonally, in response to the complex hydrology of the watershed. The concentrations of total PCBs ranged between 0.04 and 10.653ngg−1 and suggests low total PCBs sediment contamination, when compared to most international criteria. Total BuSn concentrations range between 67 and 526ng·g−1, which are relatively low when compared to most international criteria and ecological risk assessments. This is the first study of organic contamination in Ichkeul Lake (RAMSAR and UNESCO World Heritage site).

Mesocosm Studies on the Efficacy of Bioamended Activated Carbon for Treating PCB-Impacted Sediment.

This report describes results of a bench-scale treatability study to evaluate the efficacy of bioaugmentation with bioamended activated carbon (AC) for in situ treatment of polychlorinated biphenyl (PCB) impacted sediments. To this end, the ability of PCB transforming microorganisms to degrade and reduce the overall concentration of PCBs in sediment was determined in 2 L recirculating mesocosms designed to simulate conditions in Abraham's Creek in Quantico, Virginia. Ten sediment mesocosms were tested for the effects of AC alone, AC with slow release electron donor (cellulose) and different concentrations and combinations of PCB dehalogenating and degrading microorganisms added as bioamendments. A 78% reduction of total PCBs was observed using a cell titer of 5 × 105 Dehalobium chlorocoercia and Paraburkholderia xenovorans cells g-1 sediment with 1.5% AC as a delivery system. Levels of both higher and lower chlorinated congeners were reduced throughout the sediment column indicating that both anaerobic reductive dechlorination and aerobic degradation occurred concurrently. Porewater concentrations of all PCB homologues were reduced 94-97% for bioaugmented treatments. Toxicity associated with coplanar PCBs was reduced by 90% after treatment based on toxic equivalency of dioxin-like congeners. These results suggest that an in situ treatment employing the simultaneous application of anaerobic and aerobic microorganisms on AC could be an effective, environmentally sustainable strategy to reduce PCB levels in contaminated sediment.

Spatial variation of PAHs and PCBs in coastal air, seawater, and sediments in a heavily industrialized region

Concurrent coastal seawater (n=22), sediment (n=22), and atmospheric samples (n=10) were collected in the Aliaga industrial region, Turkey, to explore the spatial variation, sources, and air-seawater exchange of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Seawater Σ16PAH concentrations (particle+dissolved) ranged between 5107 and 294,624pgL-1, while Σ41PCB concentrations were in the range of 880-50,829pgL-1. Levels in sediments were highly variable ranging between 35.5-49,682 and 2.7-2450μgkg-1 in dry weight for Σ16PAHs and Σ41PCBs, respectively. Atmospheric concentrations varied between 1791-274,974 and 104-20,083pgm-3 for Σ16PAHs and Σ41PCBs, respectively. Sediment organic matter (OM) content and levels of Σ16PAHs and Σ41PCBs correlated weakly (r 2=0.19-0.23, p<0.05) suggesting that the spatial variations of PAHs and PCBs were mainly affected by local sources rather than their sorption to OM. The geographical distribution of PAH and PCB concentrations in air, seawater, and sediment and factor analysis on the sediment levels pointed out that the major sources in the region are steel plants, petroleum refinery, petrochemical complex, ship breaking, loading/unloading activities at the ports, vehicular emissions, and fossil fuel combustion emissions. The direction of the air-seawater exchange was also explored by estimating seawater fugacity fractions of PAHs and PCBs. For PAHs, the number of cases implying deposition (43.0%) and volatilization (39.5%) was similar, while for PCBs, the number of cases implying volatilization (60.4%) was much higher compared to deposition (21.6%). Fugacity fractions were generally <0.36 (deposition) at the sites close to industrial and ship breaking activities where the highest seawater and sediment levels were measured, implying that atmospheric deposition is an important mechanism affecting seawater and sediment PAH and PCB levels.