Polychlorinated biphenyls (PCBs) and Polybrominated Diphenyl Ethers (PBDEs) in surface sediments from Monastir Bay (Tunisia,Central Mediterranean): Occurrence,distribution and seasonal variations

An assessment of PCB and PBDE contamination of surface sediments in Monastir Bay was carried out in two contrasted seasons of the year. Samples were collected from 5 sites and analyzed for the ∑₇ marker PCBs (i.e. PCBs 28, 52, 101, 118, 138, 153 and 180) and ∑₄ PBDE congeners (PBDEs 47, 99, 119 and 153) by GC/ECD. Concentrations of both PCBs and PBDEs showed seasonal variations. PCB concentrations were in the range of 3.1–9.3 ng g⁻¹ and 1.1–8.1 ng g⁻¹ in wet and dry season respectively, and sediments were considered moderately contaminated with PCBs. All PCBs analyzed were detected in surface sediments. PCB 153 and 52 congeners showed the highest relative abundance in both winter and summer. PBDE concentrations ranged from not detect to 0.1 ng g⁻¹, with only BDE-47 congener detected in sediments and only in winter. Analysis of spatial and seasonal variations indicated that PCB distribution is governed by hydrodynamics and temporal variability of inputs. While the PCB contamination appeared to be mainly land-based, PBDEs are suspected to originate from atmospheric deposition.     

Polychlorinated biphenyls in the Kupa River, Croatia, Yugoslavia

The presence of polychlorinated biphenyls (PCBs) was investigated in samples of water, suspended particles, sediments and fish from the Kupa river, Croatia, Yugoslavia, along a river stretch extending up to 10 km upstream and 200 km downstream of the primary contaminated karst region. Contamination was due to improper disposal of industrial waste discharge. The PCB levels detected in the samples collected downstream ranged from 1 to 52 ng 1⁻¹ for water, from 50 to 190 μg kg⁻¹ for suspended particles and from 8 to 39 μg kg⁻¹ for the sediment. A wide range of PCB concentrations, from 0.1 to 42.3 μg g⁻¹, which were measured in edible portions of different fish confirmed a long-term contamination of the river with PCBs. As the Kupa may be classified among low to moderately contaminated waters, it is essential that the investigations of the presence and behaviour of PCBs in the river and its environment be continued.     

Accelerated delivery of polychlorinated biphenyls (PCBs) in recent sediments near a large seabird colony in Arctic Canada

Polychlorinated biphenyls (PCBs) were measured in sediment cores from ponds located near a large seabird colony at Cape Vera, Devon Island, Arctic Canada. Surface sediment PCB concentrations were ∼5× greater in seabird-affected sites relative to a nearby control pond and were correlated with independent indicators of seabird activity including, sedimentary δ¹⁵N and lakewater chlorophyll a and cadmium concentrations. PCB fluxes were amongst the highest recorded from the High Arctic, ranging from 290 to 2400 ng m⁻² yr⁻¹. Despite a widespread ban of PCBs in the mid-1970s, PCB accumulation rates in our cores increased, with the highest values recorded in the most recent sediments. Possible mechanisms for the recent PCB increases include a vertical flux step driven by seabird-delivered nutrients and/or delayed loading of PCBs from the catchment into the ponds. The high PCB levels recorded in the seabird-affected sites suggest that seabird colonies are exposing coastal ecosystems to elevated levels of contaminants.     

Distribution and ecological risk of organochlorine pesticides and polychlorinated biphenyls in sediments from the Mediterranean coastal environment of Egypt

Organochlorine contamination in the Mediterranean coastal environment of Egypt was assessed based on 26 surface sediments samples collected from several locations on the Egyptian coast, including harbors, coastal lakes, bays, and estuaries. The distribution and potential ecological risk of contaminants is described. Organochlorine compounds (OCs) were widely distributed in the coastal environment of Egypt. Concentrations of PCBs, DDTs, and chloropyrifos ranged from 0.29 to 377 ng g⁻¹ dw, 0.07 to 81.5 ng g⁻¹ dw, and below the detection limit (DL) to 288 ng g⁻¹ dw, respectively. Other organochlorinated pesticides (OCP) studied were 1–2 orders of magnitude lower. OCP and PCBs had higher concentrations at Burullus Lake, Abu Qir Bay, Alexandria Eastern Harbor, and El Max Bay compared to other sites. OCP and PCB contamination is higher in the vicinity of possible input sources such as shipping, industrial activities and urban areas. PCB congener profiles indicated they were derived from more than one commercially available mixture. The ratios of commercial chlordane and heptachlor metabolites indicate historical usage; however, DDT and HCHs inputs at several locations appear to be from recent usage. The concentrations of PCBs and DDTs are similar to those observed in sediments from coastal areas of the Mediterranean Sea. Ecotoxicological risk from DDTs and PCBs is greatest in Abu Qir Bay, Alexandria Harbor, and El-Max Bay.     

Organochlorine pesticides in surface sediments and suspended particulate matters from the Yangtze estuary, China

Total HCHs' and total DDTs' levels in surface sediments (SS) ranged from 0.5 to 17.5 ng g⁻¹ and from 0.9 to 33.1 ng g⁻¹, averaged 6.0 and 8.2 ng g⁻¹, respectively. Total HCHs' and total DDTs' levels in suspended particulate matters (SPM) varied from 6.2 to 14.8 ng g⁻¹ with a mean value of 12.3 ng g⁻¹ and were from 3.4 to 25.7 ng g⁻¹ with an average of 16.4 ng g⁻¹, respectively. Lindane is the main HCHs' source and continuing use in the Yangtze Delta areas of ‘pure’ γ-HCH (lindane) rather than technical HCH (a mix of largely α- and some γ-HCH). DDTs in SS are mainly accumulated in history. However, high DDT fractions in SPM are indicators of new input of typical dicofol type DDT from 2002 to 2004. It can be seen that most samples from the Yangtze estuary were in ranges where adverse biological effects are expected, either occasionally or frequently.     

Polychlorinated biphenyls hot and cold seasons distribution in see water,sediment, and fish samples in the Khour-e-Mousa (Mah-Shahr), Iran

The concentrations of polychlorinated biphenyls (PCBs) were assessed at four sites in Khour-e-Mousa (Mah-Shahr), Iran. Sea water, sediment and fish (cynoglossus bilineatus) samples were taken at each site and were analysed for PCB levels. To investigate the possible source of PCBs found in fish samples, sediments and waters were collected from four sites (D1, D2, D3, and D4) and studied. The relationship between PCB concentrations in sediment, water and fish is discussed. The results indicate that PCBs are detected in all fish samples and its concentration range from 3.2 to 102.7 μg kg^?1 dry weight and 5.4–149.7 μg kg^?1 dry weight in cold and warm seasons, respectively. The D2 and D4 sites were found to have the highest and lowest levels of PCB concentrations, respectively. Total congener PCB (CB, 28, 52, 44, 101, 149, 118, 153, 138, and 180) concentrations at the sediment samples for D1, D2, D3, and D4 sites ranged from 1.6 to 30.9 μg kg^?1 dry weight and 2.3–47.1 μg kg^?1 dry weight in cold and warm seasons, respectively. The total PCB concentrations for D2 site were found to be significantly higher than other three sites. Total water congener PCB (CB, 28, 52, 44, 101, 149, 118, 153, 138, and 180) concentrations ranged from 0.01 to 0.25 μg L^?1 and 0.02–0.39 μg L^?1 in cold and warm seasons, respectively.     

Halogenated organic contaminants (HOCs) in sediment from a highly eutrophicated lake, China: Occurrence, distribution and mass inventories

Halogenated organic contaminants (HOCs) including 16 polybrominated diphenyl ethers (PBDEs) and 37 polychlorinated biphenyls (PCBs) were determined in 49 surfacial sediments from Chaohu Lake, a highly eutrophicated lake, China. PBDEs were detected in almost samples with the range of the total concentration (defined as Σ₁₆PBDEs) from 0.84 to 86.6 ng g⁻¹. Compared with the occurrence of PBDEs in Pearl River Delta and Yangtze River Delta in China, lower percentage of BDE-209 over the concentration of Σ₁₆PBDEs was inferred by the high-volume application of penta-BDE mixture product for local domestic furniture purpose. The total concentration of 37 PCBs (Σ₃₇PCBs) ranged from 0.05 to 3.36 ng g⁻¹ with the most detection of PCB-1, -4, -52 and -71. Both the concentrations of Σ₁₆PBDE and Σ₃₇PCB poorly correlated with total organic carbon (TOC), suggesting the significant contribution of phytoplankton organic carbons to sediment TOC. The contamination by PBDEs and PCBs in western region of the lake was significantly more serious than in eastern lake. Our findings about the higher residues of PBDEs and PCBs in sediments at the estuary of Nanfei River compared to the other estuaries also supported the conclusion that urban area (Hefei city) was the main source of PBDEs and PCBs. The comparison with the concentration of HOC in the present study with those in other lacustrine sediments around the world suggested the contamination by PBDEs in Chaohu Lake is at middle of the global concentration range, whereas PCBs is at low end of the global range which could be elucidated by local economic development and historical usage of PBDEs and PCBs. The mass inventories of HOCs in the lake were estimated at 561 and 38 kg, which corresponds to only 0.000006% and 0.0001% of these global historical produce volumes, respectively.     

Seasonal variation of the distribution of PCBs in sediments and biota in a PCB-contaminated estuary

To elucidate the effects of seasonal variation of precipitation on the distribution of polychlorinated biphenyls (PCBs) in estuarine sediments and benthic feeders, PCB concentrations of river surface sediments and mullet fish (Liza macrolepis) were investigated in the estuary of Er-Jen River near former PCB contamination sites before and after each wet season from 2002 to 2004. Analyses of grain size distribution and organic matter revealed that the pre-existing surface sediments were covered by and mixed with the soil particulates brought by surface runoff after each wet season. Obvious increment of PCB content and significantly elevated fraction (p < 0.005) of light PCBs of the river mouth’s sediments after each wet season indicated that the invading particles were rich in unweathered PCBs. PCBs previously buried in the surface soil of heavily contaminated sites were flushed into this estuary through surface runoff. The precipitation altered the PCB patterns in sediment organic matter, the dietary source of mullet, and consequently changed that of mullets accordingly, which all possessed significant greater fraction of light PCBs. In this study, it was demonstrated that seasonal summer precipitation affected the distribution of PCBs on surface sediments and the mullets of this estuary. PCB residuals retained in this region still pose potential threats to biota resided here.     

Levels,congener profile and inventory of polychlorinated biphenyls in sediment from the Songhua River in the vicinity of cement plant,China: a case study

This study investigated the contamination levels, homologue, and congener profiles and evaluated the residue inventory of polychlorinated biphenyls (PCBs) in sediment of the Songhua River in the vicinity of cement plant. The total concentration of detected 35 PCB congeners ranged from 1.12 to 2.19 ng/g dry weight (dw) in sediment, with a mean value of 1.56 ng/g dw, and the concentration of PCBs decreased in the following order: the downstream?>?cement plant?>?upstream. The results of total organic carbon (TOC)-normalized PCB concentrations indicate that the sediments have low potential ecological risk in this area. The study results on homologue and congener of PCBs show that the emissions from cement production could be the major sources of PCBs in sediment, and the low-chlorinated PCBs will be exchanged among air, water, and sediment with increasing temperature during summer and flow to downstream with water during the wet season. The spatial density and total burden of PCBs in the surface sediments were 17.2 ng/cm² and 1.2 kg, respectively. To our knowledge, this study is the first to explore the pollution characteristics of unintentionally produced PCB emissions from cement industry by means of monitoring sediment samples.     

Persistent organic pollutants associated to water fluxes and sedimentary processes in the Colorado River delta, Baja California, México

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were studied in sediment cores from two distinctive modern channels of the Colorado River (CR) delta. Their abundance and temporal changes are associated with flood-flows from the CR across the USA-Mexico border. The CR channel is directly exposed to river flood-flows while the Hardy River (HR) is a local channel derived mainly from agricultural runoff, geothermal effluents, and treated urban wastewater. Different headwater compositions and degrees of exposure to flood-flows appear to be the factors controlling the composition of persistent organic pollutants (POPs). Enrichment of OCPs (46 ng g⁻¹ dwt in HR and 4.37 ng g⁻¹ dwt in CR) occurred during or a few years after flooding. PCB-138 (4.2 ng g⁻¹ dwt) is enriched in HR suggesting its origin in dielectric oils from the geothermal power plant. PCB-28 (2.1 ng g⁻¹ dwt) in CR may be related with atmospheric input and/or re-deposition of upstream sediments. In surficial sediments (0-3 cm), only HR exceeds international sediment quality guidelines (4,4′-DDE = 8.16 ng g⁻¹ dwt and ΣDDT = 8.34 ng g⁻¹ dwt).     

Polychlorinated biphenyls in surface sediments of Yueqing Bay, Xiangshan Bay, and Sanmen Bay in East China Sea

The spatial distribution and source of polychlorinated biphenyls (PCBs) in 30 surface sediments of Yueqing Bay, Xiangshan Bay, and Sanmen Bay in Eastern China were analysed. Total concentrations of PCBs ranged from 9.33 to 19.60 ng g⁻¹ dry weight for all the sampling stations. The observed PCB levels were lower than those in areas of high urbanisation or contamination in the bay. Low-chlorinated PCBs, dominated by tri-PCB, were identified as the prevalent contaminate of surface sediments, and the top three PCB congeners were lighter chlorinated congeners (PCB 8, PCB 18 and PCB 28). These results were in agreement with the fact that tri-PCB compounds are the dominant contaminants in China. The result of the principal component analysis revealed that all samples were similar in composition to Aroclor 1242, suggesting they might originate from electrical capacitors and transformers. The levels of PCBs were significantly correlated with the total organic carbon in the sediments.     

Polybrominated diphenyl ethers in sediments of the Daliao River Estuary, China: levels, distribution and their influencing factors

The concentrations, compositional profiles, possible sources of polybrominated diphenyl ethers (PBDEs) in sediments of the Daliao River Estuary as well as the factors influencing the distribution of PBDEs were investigated. The total concentrations of PBDEs ranged from 0.13 to 1.98 ng g⁻¹ d.w. BDE209 was the dominating congener in all sediment samples, indicating the pollution of PBDEs in the Daliao River Estuary mainly came from the use of deca-BDE commercial mixtures. The intrusion of sea waters promoted the deposition of the colloid-associated PBDEs in the estuary. There were significantly negative correlations between PBDE concentration in sediment with pH value and salinity in the bottom water. The higher river flow in the flood season (summer) obviously accelerated the transport of PBDEs, and thereby increased the risk of PBDE contamination to the deep ocean. Moreover, a positive correlation between TOC and PBDE distributions was observed, suggesting that TOC regulated the distributions of PBDEs in sediments of Daliao River Estuary.     

Spatial distribution of organochlorine contaminants in soil, sediment, and fish in Bikini and Enewetak Atolls of the Marshall Islands, Pacific Ocean

Several nuclear tests were performed at Enewetak and Bikini Atolls in the Marshall Islands between 1946 and 1958. The events at Bikini Atoll involved several ships that were tested for durability during nuclear explosions, and 24 vessels now rest on the bottom of the Bikini lagoon. Nine soil samples were collected from different areas on the two islands of the atoll, and eighteen sediment, nine fish, and one lobster were collected in the vicinity of the sunken ships. Organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polychlorinated terphenyls (PCTs) in these samples were analyzed using gas chromatography/ion trap mass spectrometry (GC/ITMS). The average recoveries ranged from 78% to 104% for the different PCB congeners. The limits of detection (LOD) for PCBs, PCTs, DDE, DDT, and dieldrin ranged 10-50 pg g⁻¹. Some fish from Enewetak contained PCBs at a concentration range of 37-137 ng g⁻¹, dry weight (dw), and most of the soils from Enewetak showed evidence of PCBs (22-392 ng g⁻¹ dw). Most of the Bikini lagoon sediment samples contained PCBs, and the highest was the one collected from around the Saratoga, an aircraft carrier (1555 ng g⁻¹ dw). Some of the fish samples, most of the soil samples, and only one of the sediment samples contained 2,2-bis(4-chlorophenyl)-1,1-dichloroethylene (DDE) and PCBs. In addition to PCBs, the soils from Enewetak Atoll contained PCTs. PCTs were not detected in the sediment samples from Bikini Atoll. The results suggest local pollution sources of PCBs, PCTs, and OCPs.     

Polychlorinated biphenyls (PCBs) residues in milk from an agroindustrial zone of Tuxpan, Veracruz, Mexico

The coasts of the Gulf of Mexico are zones exposed to the exploration and exploitation of petroleum sources, and the products generated in agricultural zones may become contaminated by persistent organic pollutants (POPs). The objective of the present study was to evaluate the presence of polychlorinated biphenyl compounds (PCBs) in milk from dairy production units near sources of environmental pollutants. It was confirmed that the seven congeners of nondioxin-like PCBs (NDL-PCBs) are present in milk where compounds PCB101, PCB118, PCB153 and PCB180 appear in 100% of the samples analyzed, the rank of concentration for the sum of the seven congeners fluctuating between 2.6 and 26 ng g⁻¹ with a median of 6 ng g⁻¹. None of the samples surpassed the provisional value established by the EU of 40 ng g⁻¹ of milk fat for the sum of the seven congeners, indicator that was not affected by the season of the year (p < 0.05), whose median of 8.6 ng g⁻¹ and 6.3 ng g⁻¹ for rain and drought respectively. The concentrations of NDL-PCBs found in milk do not represent a problem for human health; however, they alert the existence of spontaneously generated, uncontrolled sources that may represent a potential danger for human and animal health.     

Spatial distribution of polychlorinated biphenyls (PCBs) and polybrominated biphenyl ethers (PBDEs) in an e-waste dismantling region in Southeast China: Use of apple snail (Ampullariidae) as a bioindicator

Fengjiang is a large e-waste dismantling site located in southeast China. In this paper, apple snail and soil samples were collected from this e-waste dismantling site and 25 vicinal towns to investigate the contamination status, spatial distributions and congener patterns of polychlorinated biphenyls (PCBs) and polybrominated biphenyl ethers (PBDEs). Total PCB concentrations in apple snails (3.78-1812 ng g⁻¹ dry weight (dw)) were significant higher than that in soil samples (0.48-90.1 ng g⁻¹ dw). PBDE (excluding BDE 209) concentrations in apple snail and soil samples ranged from 0.09 to 27.7 ng g⁻¹ dw and 0.06 to 31.2 ng g⁻¹ dw, respectively. Concentrations of PCBs and PBDEs in snails and soils correlated negatively with the distance from Fengjiang. Both the concentrations and profiles of the pollutants were significantly correlated (p < 0.05) between the snail and soil samples, indicating the suitability of apple snail as a reliable bioindicator for PCBs and PBDEs contamination in this region. Relatively high concentrations of PCBs and PBDEs at locations far from e-waste dismantling sites implied that these pollutants have been transported to surrounding regions.     

Altitude dependence of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in surface soil from Tibetan Plateau, China

Remote mountain areas besides high latitude regions are beginning to receive increased attention in studying the transport and behavior of persistent organic pollutants (POPs). In the present work, surface soil samples were collected from the Tibetan Plateau, the highest plateau in the world which includes the northern slope of Mt. Qomolangma, to investigate the levels and trends of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) along the altitudinal gradient. The average PCB and PBDE concentrations were 185.6 ng kg⁻¹ dry weight (dw) (range 47.1–422.6 ng kg⁻¹ dw) and 11.1 ng kg⁻¹ dw (range 4.3–34.9 ng kg⁻¹ dw), respectively. Regression analysis between the log-transformed TOC-normalized concentrations and the altitudes of the sampling sites showed two opposite trends with regard to altitude dependence: negative relationship with altitude below about 4500 m followed by a positive altitude dependence above this point. Considering minimum anthropogenic activities and very sparse precipitation in the north of Himalayas, the trends above 4500 m imply that the significant altitude dependence of these two groups of POPs were irrespective of pollution sources, but could be predicted by the global distillation effect involving cold condensation in high altitude mountain areas. Increasing levels of heavier congeners were found in higher altitude sites, although the lighter congeners were the main contributors to the total amount, suggesting that less volatile congeners seem to become enriched easier than those more volatile at higher altitudes in this region.     

Mercury transport between sediments and the overlying water of the St. Lawrence River area of concern near Cornwall, Ontario

Contaminated sediments in the St. Lawrence River remain a difficult problem despite decreases in emissions. Here, sediment and pore water phases were analyzed for total mercury (THg) and methyl mercury (MeHg) and diffusion from the sediment to the overlying water was 17.5 ± 10.6 SE ng cm⁻² yr⁻¹ for THg and 3.8 ± 1.7 SE ng cm⁻² yr⁻¹ for MeHg. These fluxes were very small when compared to the particle-bound mercury flux accumulating in the sediment (183 ± 30 SE ng cm⁻² yr⁻¹). Studies have reported that fish from the westernmost site have higher Hg concentrations than fish collected from the other two sites of the Cornwall Area of Concern, which could not be explained by differences in the Hg flux or THg concentrations in sediments, but the highest concentrations of sediment MeHg, and the greatest proportions of MeHg to THg in both sediment and pore water were observed where fish had highest MeHg concentrations.     

Spatial character of polychlorinated biphenyls from soil and respirable particulate matter in Taiyuan, China

As one of China’s great metropolises, Taiyuan is affected by heavy chemical industry and manufacture of chemical products, and faces pollution from polychlorinated biphenyls (PCBs). Therefore, this study was conducted to determine the PCB concentrations in various environmental media in Taiyuan. We collected 15 soil samples, 34 respirable particulate matter (PM) samples (17 of PM_2.5 and 17 of PM₁₀) from urban areas of Taiyuan, and measured a total of 144 PCB congeners (including some coeluting PCB congeners). The total PCB concentrations were 51–4.7 × 10³ pg g⁻¹ in soil, 27–1.4 × 10² pg m⁻³ in PM_2.5 and 16–1.9 × 10² pg m⁻³ in PM₁₀. Of the PCB homologues, the dominant PCBs detected in the various media were all tri-CBs. Soil was relatively the most polluted media. Furthermore, principal-component analysis revealed that the major PCB source in Taiyuan may be associated with the main commercial PCB through long-range transmission. Toxic equivalency (TEQ) concentrations (based on ten dioxin-like PCBs) ranged from N.D. to 5.9 × 10⁻³ pg-WHO TEQ g⁻¹ in soil, 2.0 × 10⁻⁴–3.4 × 10⁻³ pg-WHO TEQ m⁻³ and 1.0 × 10⁻⁴–1.2 × 10⁻³ pg-WHO TEQ m⁻³ in PM_2.5 and PM₁₀, respectively. In previous studies, PCBs were not a severe component of contaminant in Taiyuan; however, this study suggested there is a potential threat of human exposure to PCBs for residents of Taiyuan.     

Polychlorinated dibenzo-p-dioxins, dibenzofurans and polychlorinated biphenyls levels in human breast milk from different regions of Turkey

Human breast milk offers the optimal nutrition for all infants and have been widely used in biomonitoring programs to assess human exposure to lipophylic environmental contaminants such as polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF) and polychlorinated biphenyls (PCB). There are no previous reports from Turkey on chemically determined levels of PCDDs, PCDFs, and PCBs in human breast milk expressed as World Health Organization (WHO) toxic equivalents (TEQ). To get an overview of the levels of these contaminants in Turkish human milk, samples from 51 Turkish women living in the Ankara, İstanbul, Antalya, Kahramanmaraş, and Afyon provinces were analyzed by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) throughout 2007. The mean concentrations of WHO_PCDD/F-TEQ and WHO_PCB-TEQ of all samples from the five regions were 7.5 and 3.1 pg g⁻¹ on a lipid basis, respectively. PCDD/F concentrations ranged between 0.78 and 29.3 pg WHO-TEQ g⁻¹ fat (1.7 and 36.2 pg WHO-TEQ g⁻¹ fat, respectively, including PCB). Of the five studied locations, the lowest levels of ∑TEQs (PCDD/F + PCB) were found in the Afyon (6.8 pg WHO-TEQ g⁻¹ fat) and the highest in the Antalya (15.6 pg WHO-TEQ g⁻¹ fat) province. The results have been discussed in terms of regions and PCDD/F and PCBs for which analyses had been made. The mean levels of PCDD/Fs and PCBs in Turkish human milk are comparable to that found in other countries.     

Measurement and modeling of urban atmospheric PCB concentrations on a small (8 km) spatial scale

Atmospheric transport and deposition of polychlorinated biphenyls (PCBs) is an important problem for ecosystems around the world. Data from several monitoring networks demonstrate that atmospheric PCB concentrations are dramatically elevated in urban areas compared to rural or background regions, such that these urban emissions of PCBs support the regional and global transport and deposition of PCBs to more remote areas. Identifying and controlling the sources of urban atmospheric PCBs is thus essential in minimizing the regional and global transport and deposition of these compounds. From December 1999 to November 2000, gas-phase PCB concentrations were measured at two monitoring locations, 8 km apart, within the New York City metropolitan area, at Jersey City and Bayonne, NJ. Concentrations, congener patterns, and temporal patterns of PCBs differ dramatically at the two sites, suggesting that a significant source of atmospheric PCBs exists within 8 km of the Bayonne site, resulting in spikes in gas-phase PCB concentration at Bayonne that are not observed at Jersey City. The Regional Atmospheric Model System (RAMS) coupled with the Hybrid Particle and Concentration Transport model (HYPACT) was used to estimate that the PCB source near Bayonne emits a flux of ΣPCBs on the order of 100 g d⁻¹. Extrapolation of this source magnitude to the area of New York City suggests that this urban area emits at least 300 kg yr⁻¹ ΣPCBs to the regional atmosphere, similar in magnitude to the flow of ΣPCB out of the Upper Hudson River into the New York/New Jersey Harbor.