Polycyclic aromatic hydrocarbons in rainwater

A study on polycyclic aromatic hydrocarbons (PAH) in rainwater was carried out over periods of at least one year at two locations in Belgium with different environments. Maximum amounts and concentrations of PAH were reached during the winter period, mainly due to household heating. This influence was also reflected in the relative proportions of the six PAH measured. For comparable periods the amounts of PAH were almost proportional to the quantity of rain. With the available data, and as most of the rainfall is coming from the same wind direction, it was not feasible to localise possible pollution sources based upon the distribution of PAH over the different windsectors, nor was it possible to identify significant differences for both sampling locations due to their different surroundings, indicating that the rain plays an important role in the transport and distribution of pollutants over a wide area. Between about 100 and 170 μg m^?2 PAH and 2 to 3 g m^?2 of total organic carbon content (TOC) per year were deposited by the rain, corresponding to mean concentrations of about 140 ng l^?1 of PAH and 2.9 mg l^?1 of TOC.     

Polycyclic aromatic hydrocarbons in air samples of meat smokehouses.

In a screening programme nine Danish meat smokehouses were randomly selected for measurements on concentration of airborne polycyclic aromatic hydrocarbons (PAH). A total of 23 stationary air samples were collected during the entire working period of the kiln either above the kiln doors or approximately 2 m in front of the kiln doors (i.e. total exposure on the day of sampling). Three of these samples had a PAH content below the detection limit of the highly sensitive assay employed. Furthermore, eight personal air samples were collected during the periods of tending the kiln (i.e. peak exposure measurement). Three of these samples were below the detection limit. Total airborne PAH concentration of the stationary air samples calculated as the sum of the concentration of 16 selected PAH compounds, was in general far lower than the total airborne PAH concentration measured in the same manner in smokehouses curing fish (Nordholm et al., 1986). In contrast to the study on PAH exposure in smokehouses curing fish, the present study revealed no significant difference between total PAH content in air samples collected above the kilns compared with samples collected approximately 2 m in front of the kiln doors. Calculation of the relative content of the individual PAH compounds in the stationary air samples collected in meat smokehouses showed naphthalene to be the major compound in (70% +/- 26% of total PAH), whereas the relative content of carcinogenic PAH compounds in average represented 4.0% of the total PAH content. However, only approximately 15% of the stationary air samples with detectable content of total PAH contained detectable amounts of carcinogenic PAH compounds. Hence it was concluded that PAH exposure during cold meat curing might be considered a limited health hazard compared with PAH exposure during hot fish curing.     

Polycyclic aromatic hydrocarbons in diesel exhaust emissions

Samples of diesel exhaust emissions were analysed for eleven polycyclic aromatic hydrocarbons (PAHs) by high performance liquid chromatography (HPLC) with flourescence detection. The PAHs present in the diesel extracts were then represented by a PAH profile with reference to the concentration of benzo(a)pyrene.     

Polycyclic aromatic hydrocarbons in remote mountain lake waters

Polycyclic aromatic hydrocarbons (PAH), including alkylated and sulfur derivatives, were identified and measured in the waters from three European remote mountain lakes during both ice-free and ice covered periods. The measured concentrations were in the same order in all three lakes (700-1100 pg/l). The PAH patterns in both dissolved and particulate water phases were dominated by the low molecular weight compounds (i.e. phenanthrene, fluoranthene and pyrene) in Lakes Redó (Pyrenees) and Gossenk?lle (Alps). In contrast, the high molecular weight (HMW) compounds (i.e. chrysene+triphenylene, benzofluoranthenes, benzo[e]pyrene) were very significant in lake Ovre Ne?dalsvatn (Caledonian). These HMW PAH correspond to mixtures originating from high temperature combustion processes which have been photodegraded during long range atmospheric transport and parallel the PAH mixtures encountered in the underlying lake sediments. In contrast, dissolved PAH exhibit temperature dependence with higher concentrations found at water temperatures below 6-7 degrees C reflecting higher condensation from the atmospheric gas phase reservoir.     

Polycyclic aromatic hydrocarbons in dustfall in Tianjin, China

Atmospheric dustfall samples from 23 locations in Tianjin, China, were collected and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs) classified by the Environmental Protection Agency as priority pollutants from March 2002 to March 2003. SigmaPAH16 (sum of 16 PAH compounds) concentrations in the dustfall collected during heating season ranged from 2.5 to 85.5 mug/g, while that during the non-heating season varied from 1.0 to 48.2 microg/g dry weight. The dominant components in the heating season included naphthalene, phenanthrene, fluoranthene, and chrysene, while naphthalene, fluorene, phenanthrene, and fluoranthene were dominant during the non-heating season. Compared with the non-heating season, the heating season was characterized by a higher fraction of high-molecular-weight PAHs with four to six rings with exception of the samples from the east industrial area. The east industrial area had more significant correlations between individual PAH compounds, and more discrete triangular components of three-, four-, five- and six-ring PAHs. No significant correlations were observed between the PAHs concentrations and total organic carbon (TOC) in the dustfall samples. The deposition fluxes of sigmaPAH15 (sum of 15 PAHs except naphthalene), sigmaPAH6 (sum of 6 carcinogenic PAHs recommended by IARC) and benzo[a]pyrene (BaP) from atmospheric deposition to the whole area were estimated as 1911, 196, and 53 microg/m2/year, respectively. The deposition rates for PAH compounds in the east industrial area were higher than those in the urban and rural areas. Furthermore, the deposition contribution of PAHs during domestic heating season in winter was not significant relative to the annual inputs.     

Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in sediments from the Mersey Estuary, U.K

Sediments from the Mersey Estuary were analysed for polycylic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Total PAH concentrations ranged from 626 to 3766 microg/kg and total PCB concentrations ranged from 36 to 1409 microg/kg. These concentrations are intermediate in comparison to other U.K estuaries with similar histories of industrialisation and urbanisation. The distribution of individual PAHs were consistent throughout the Mersey Estuary, this together with molecular indices suggests mainly pyrolitic inputs, augmented by a variety of industrial petrogenic sources. Comparison of tri-to-hepta PCB congeners revealed multiple sources and inputs throughout the estuary. A sediment core collected in close proximity to Garston Docks revealed the take-off, peak pollutant input and recent decline of PCB pollution. However, a second depth profile of sediments at Ellesmere Port showed little change in total or individual PCB concentrations due to extensive sediment reworking and mixing.     

Polycyclic aromatic hydrocarbons: levels and phase distributions in preschool microenvironment

This work aims to characterize levels and phase distribution of polycyclic aromatic hydrocarbons (PAHs) in indoor air of preschool environment and to assess the impact of outdoor PAH emissions to indoor environment. Gaseous and particulate (PM₁ and PM_2.5) PAHs (16 USEPA priority pollutants, plus dibenzo[a,l]pyrene, and benzo[j]fluoranthene) were concurrently sampled indoors and outdoors in one urban preschool located in north of Portugal for 35 days. The total concentration of 18 PAHs (ΣPAHs) in indoor air ranged from 19.5 to 82.0 ng/m³; gaseous compounds (range of 14.1–66.1 ng/m³) accounted for 85% ΣPAHs. Particulate PAHs (range 0.7–15.9 ng/m³) were predominantly associated with PM₁ (76% particulate ΣPAHs) with 5‐ring PAHs being the most abundant. Mean indoor/outdoor ratios (I/O) of individual PAHs indicated that outdoor emissions significantly contributed to PAH indoors; emissions from motor vehicles and fuel burning were the major sources.     

Polycyclic aromatic hydrocarbons (PAHs) in bottom sediments of the Kara Sea shelf,Gulf of Ob and Yenisei Bay

PAH concentration and distribution has been examined in surface sediments samples from the Kara Sea, Russia. The study includes 13 samples from the South-eastern Kara Sea shelf, one sample from the south-western part of the sea, 4 samples from the Baydaratskaya Bay, 5 samples from the Gulf of Ob and 4 samples from the Yenisei Bay, collected in August-September 1993-1994. Cluster analysis and principal component analysis (PCA) were used to identify common patterns and possible sources of PAHs. The total PAH concentration (sum of two- to six-ring aromatic hydrocarbons) in the Kara Sea sediments was generally lower than in the Barents Sea sediments and comparable to the levels in the Pechora and White seas. Two- and three-ring aromatic hydrocarbons predominated in Kara Sea sediments, which indicate a relatively stronger petrogenic origin than that in the adjacent seas. The highest total PAH concentrations within the Kara Sea were found in sediments from the Yenisei Bay and in the South-western part of the Kara Sea in the Eastern Novaya Zemlya Trough. The PAHs of the Yenisei Bay sediments were dominated by perylene and PAHs of petrogenic origin, but had also a strong indication of PAHs of pyrogenic origin. The dominating PAH group in the South-western part of the Kara Sea were four- to six-ring aromatic hydrocarbons, indicating pyrogenic origin. Perylene levels were high in all the Kara Sea samples, and highest levels were found in areas of strong terrigenous influence. The most probable source is decaying peat products being transported to the Kara Sea by both large and small rivers.     

Polycyclic aromatic hydrocarbons inside and outside of apartments in an urban area

In the context of environmental monitoring in Berlin polycyclic aromatic hydrocarbon (PAH) concentrations in air and household dust were measured inside 123 residences (and simultaneously in a sub group in the air outside the windows). The aim of this study was to determine exposure to PAHs in the environment influencing by several factors, for instance, motor vehicle traffic in a populous urban area. Indoor air samplings were carried out in two periods (winter and spring/summer) in smokers and non-smokers apartments. Benzo(a)pyrene (BaP) median values were 0.65 ng m(-3) (winter) and 0.27 ng m(-3) (spring/summer) in smokers' apartments and 0.25 ng m(-3) (winter) and 0.09 ng m(-3) (spring/summer) in the apartments of non-smokers. The median BaP content in ambient air was 0.10 ng m(-3) (maximum: 1.1 ng/m(-3)) with an indoor-outdoor mean concentration ratio of 0.9 in non-smoker households and 5.4 in smoker apartments. In household dust we obtained median values of 0.3 mg kg(-1) (range: 0.1-1.4 mg kg(-1)). We found a significant relation between indoor and outdoor values. Approximately 75% of the variance of indoor air values was caused by the corresponding BaP concentrations in the air outside the apartment windows. Otherwise a significant correlation between indoor air and household dust values cannot be found. Therefore, according to our results, it is suggested that the indoor PAH concentration in non-smoker apartments could be attributed mainly to vehicular emissions.     

Polycyclic aromatic hydrocarbons in storm runoff from urban and coastal South Carolina

Stormwater runoff was collected in urbanized areas of South Carolina to investigate the levels and sources of polycyclic aromatic hydrocarbons (PAHs). Mean concentrations of total PAHs in runoff (sum(PAHs), 14 compounds), determined by gas chromatography-mass spectrometry, were 5590 ng/l in the city of Columbia and 282 ng/l in the coastal community of Murrells Inlet. Lower concentrations were found in estuarine water at Murrells Inlet (mean = 35 ng/l) and at undeveloped North Inlet estuary (13 ng/l). The PAH profiles in Columbia and Murrells Inlet runoff were similar to those of atmospheric particulate matter and unlike those in used crankcase oil. Examination of the aliphatic fraction of Columbia runoff samples by gas chromatography with flame ionization detection showed patterns that were more similar to used crankcase oil than to urban aerosols.     

Polycyclic aromatic hydrocarbons, elemental and organic carbon emissions from tire-wear

Tire-wear is an important source of PAHs, elemental carbon (EC) and organic carbon (OC). The emissions of these pollutants have been studied in an experimental set-up, simulating a realistic road-tire interaction (summer tire-concrete road). The large particle non-exhaust emissions (LPNE; diameter greater than 10 μm) have been evaluated over 14,500 km run of the tire. An increasing linear trend with cumulative km run was observed for emissions of PAHs and carbon. Amongst PAHs in LPNE, pyrene has been observed to be the highest (30 ± 4 mg kg^− 1) followed by benzo[ghi]perylene (17 ± 2 mg kg^− 1). Different fractions of EC-OC for tire-wear have been analyzed, and unlike exhaust emissions, EC1 was observed to be 99% of EC whereas more than 70% of the OC was the high temperature carbon (OC3 and OC4). The overall emission factors (mass tire^− 1 km^− 1) for PAHs, EC and OC from tire-wear are 378 ng tire^− 1 km^− 1, 1.46 mg tire^− 1 km^− 1 and 2.37 mg tire^− 1 km^− 1 for small cars.     

Spatial and vertical distribution of polycyclic aromatic hydrocarbons in mangrove sediments

The distribution and historical changes of polycyclic aromatic hydrocarbons (PAHs) contamination in mangrove sediments in Hong Kong SAR were investigated. Surface sediments (2-3 cm) collected from four mangrove swamps exhibited significant spatial variations in concentrations of total PAH (with SigmaPAHs ranging from 56 to 3758 ng g(-1) dry wt), as well as the composition of 16 USEPA priority PAH compounds. Within a small swamp with an area of 0.68 ha, the total PAH concentrations also differed from sampling site to site, indicating that the PAH contamination is localized and confined to a very small area within the same swamp. Discharges from municipal and industrial wastewater, urban runoff, oil leakage from boats and ships, and accidental oil spill are possible sources of the PAH contamination. The sediment depth profiles reveal that the surface sediment layer (0-5 cm) had lower total PAH concentrations than that in the bottom layer (15-20 cm), and PAH composition also changed with the sediment layers. Based on the estimated annual sediment deposition rate in Hong Kong SAR of around 0.4-0.5 cm, the present findings suggest that the PAH contamination was most serious between 1958 and 1979 but started to decline thereafter. Such decline was probably due to changes in petroleum usage in urban areas and a better control of wastewater discharges from 1980 onwards in this region.     

Polycyclic aromatic hydrocarbons in soil and surface marine sediment near Jubany Station (Antarctica). Role of permafrost as a low-permeability barrier

Although Antarctica is still considered as one of the most pristine areas of the world, the growing tourist and fisheries activities as well as scientific operations and their related logistic support are responsible for an increasing level of pollutants in this fragile environment. Soils and coastal sediments are significantly affected near scientific stations particularly by polycyclic aromatic hydrocarbons (PAHs). In this work sediment and soil were sampled in two consecutive summer Antarctic expeditions at Potter Cove and peninsula, in the vicinity of Jubany Station (South Shetland Islands). Two- and 3-ring PAHs (methylnaphthalene, fluorene, phenanthrene and anthracene) were the main compounds found in most sites, although total PAH concentrations showed relatively low levels compared with other human-impacted areas in Antarctica. Pattern distribution of PAHs observed in samples suggested that low-temperature combustion processes such as diesel motor combustion and open-field garbage burning are the main sources of these compounds. An increase in PAH concentrations was observed from surface to depth into the active soil layer except for a unique sampling site where a fuel spill had been recently reported and where an inverted PAH concentration gradient was observed. The highest level was detected in the upper layer of permafrost followed by a sharp decrease in depth, showing this layer is acting as a barrier for downward PAH migration. When PAH levels in soil from both sampling programs were compared a significant decrease (p<0.01) was observed in summer 2005 (range at 75-cm depth: 12+/-1-153+/-22 ng/g) compared to summer 2004 (range at 75-cm depth: 162+/-15-1182+/-113 ng/g) whereas concentrations in surface sediment collected nearby the station PAHs increased drastically in 2005 (range: 36+/-3-1908+/-114 ng/g) compared to 2004 (range: 28+/-3-312+/-24 ng/g). Precipitation regime and water run off suggest that an important wash out of soil-PAHs occurred during the interval time between samplings. Results showed that the present PAH contamination level of Jubany Station is relatively low compared to other reported cases in Antarctica but also suggests that an increase in rain and in thawing processes caused by the global warming could result in an important soil-associated PAH mobilization with unpredictable consequences for the biota of Potter Cove.     

Polycyclic aromatic hydrocarbons (PAHs) in agricultural soil and vegetables from Tianjin

Several types of vegetables were collected from two contaminated sites in Tianjin, China. The bulk soil and the rhizosphere soil samples were also collected from the same plots. Sixteen PAHs in the samples were measured. The total concentrations of PAH16 in the bulk soil from the two sites were 1.08 and 6.25 microg/g, respectively, with similar pattern. The concentrations of PAH16 and individual compounds in the rhizosphere were significantly higher than those in the bulk soil with mean values of 2.25 and 7.82 microg/g for the two sites, respectively. The contents of both total and dissolved organic matter in the rhizosphere were also higher than those in the bulk soil. Almost all PAH compounds studied were detected in both roots and aerial parts of the vegetables studied. Abundance of higher molecular weight PAHs in vegetable, however, was lower than that in soil. Concentrations of PAH16 in vegetable were higher than those reported in the literature for other areas. It appears that agricultural soils and vegetables in Tianjin, especially those from the site located immediately next to an urban district and irrigated with wastewater for several decades, are severely contaminated by PAHs. Among the eight types of vegetable studied, the highest concentration of PAHs was found in cauliflower. By average, the concentration of PAH16 in the aerial part of vegetables was 6.5 times higher as that in vegetable root, suggesting that foliar uptake is the primary transfer pathway of PAHs from environment to vegetables.     

Polycyclic aromatic hydrocarbons (PAHs) and organochlorines (OCs) in bottom sediments of the Guba Pechenga,Barents Sea,Russia

Surface sediment samples from the Guba Penchenga and adjacent areas: Varangerfjord, Guba Malaya Volokovaya and Guba Bol'shaya Volokovaya (south-western Barents Sea) collected in March-April 1997 were analysed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated pesticides: p,p'-DDT, p,p'-DDE, p,p'-DDD, alpha- and gamma-HCH, and hexachlorobenzene (HCB). Mean summation operator PAH (sum of the two- to six-ring PAHs) concentration in sediments from the Guba Pechenga (1481 ng/g dry wt.) was significantly higher than in sediments from adjacent areas (252 ng/g dry wt.), where PAH contamination levels were similar to reported for unpolluted sediments of the northern Norway fjords and open parts of the Barents Sea. Differences between HCB levels as well as summation operator HCH (sum of alpha- and gamma-HCH) levels found in Guba Pechenga sediments and adjacent area sediments were not significant. Concentrations of these contaminants varied in ranges 0.28-1.76 and 0.05-0.68 ng/g dry wt., respectively, and were consistent with literature data on PAH levels in sediments from the northern Norway harbours, Kola Bay (Russia) and south-eastern part of the Barents Sea. Average total DDT concentration in Guba Pechenga sediments (10.5 ng/g dry wt.) was one and 2-3 orders higher than those found in sediments from the Pechora Sea and from the seas of eastern Arctic, respectively, however, it was comparable with DDT levels reported for harbours of northern Norway and Kola Bay. Significant difference between total DDT levels in Guba Pechenga and in the adjacent areas (mean 1.8 ng/g) was found. Among compounds of DDT family, p,p'-DDT isomer prevailed in all sediment samples indicating a possible local 'fresh' DDT source. Mean summation operator PCB (sum of PCB-28, 31, 52, 101, 118, 105, 153, 138, 156, 180, 209) concentration in the Guba Pechenga sediments (12.8 ng/g dry wt.) was significantly higher than in sediments of adjacent areas (2.1 ng/g dry wt.), but it was lower in comparison with summation operator PCB levels reported for the northern Norway harbours and Kola Bay sediments. The highest levels of contaminants were found in sediments collected close to the Liinakhamari harbour. The origin of both PAHs and OCs in the Guba Pechenga sediments is a combination of local sources and long-range transport from lower latitudes.     

Polycyclic aromatic hydrocarbons associated with particles in ambient air from urban and industrial areas

This study takes into consideration an analysis of the chemical polycyclic aromatic hydrocarbon (PAH) profile and its distribution in inhalable and respirable particulate matter in urban and industrial areas in La Plata, Argentina, and Leipzig, Germany. Representative samples from three locations in La Plata (industrial, traffic influenced and control area) and two locations in Leipzig (traffic influenced and control area) were obtained in summer and winter. The sampling of particulate matter was carried out with high volume collectors using cascade impactors to separate six size fractions. PAHs were extracted with hexane through a solid-liquid equilibrium extraction and analysed by HPLC/UV/fluorescence detection. The results showed a PAH seasonal behaviour in both regions, with lower contents in summer and higher ones in winter. Highest concentrations of total PAHs were found in the industrial area in La Plata. The size distribution of particles demonstrates the greater relevance of smaller particles. More than 50% of PAHs were associated with particles of less than 0.49 microm. Moreover, this particle size fraction was associated with traffic, whereas other sources of combustion were related also to particles between 0.49 and 0.95 microm. Considering the ratio of benzo(ghi)perylene (BgP)/benzo(a)pyrene (BaP) as an indicator for traffic influence, it was observed that La Plata City was more affected than Leipzig by the same proportion in summer and in winter. The BgP/InP (indeno(123-cd)pyrene) ratio was lower in winter than in summer in both places and indicates the presence of domestic combustion sources. It is important to point out the significance of using fingerprint compound ratios to identify possible sources of pollution with PAHs bound to particles.     

Polycyclic aromatic hydrocarbons in petroleum products for medicinal and cosmetic uses — analytical procedure

Two methods for extraction and determination of benzo[a]pyrene and other PAH in liquid and white soft paraffins, widely used for medicinal and cosmetic purposes, are compared. A method based on extraction by frontal elution chromatography, column and thin-layer chromatography and final spectrophotofluorometric determination gave the best results in the determination of the very low levels (ng/g) of PAH present in these fully refined samples. The complete analytical procedure showed an acceptable percentage of recoveries and good applicability to routine analysis of the PAH content in these petroleum products for the proper evaluation of their potential hazards to human health.     

Polycyclic aromatic hydrocarbons in fish from remote and high mountain lakes in Europe and Greenland

Polycyclic aromatic hydrocarbons (PAHs) were analysed in liver of fifty-seven individual trout distributed among seven high mountain lakes in Europe and one remote lake in Greenland. In all cases, very similar distributions were observed in which phenanthrene largely predominated and fluoranthene and pyrene were the second major compounds. These distributions were similar to those observed in the dissolved fraction of the waters studied in three of these lakes. The range of concentrations of PAH in fish liver show only a five-fold variation, which is considerably smaller than the range more than two orders of magnitude of sedimentary PAH concentrations of these lakes. No correlation between PAH content in sediments and fish liver has been found both at the level of total and individual compounds. However, lake site is the main statistically significant factor of variability between PAH concentrations in fish liver. Changes in fish species explain significant differences in liver content of some PAHs. Within lake, condition factor and liver concentration are inversely correlated. Female fish display lower average concentrations than male in all lakes but the differences are not statistically significant. No correspondence between fish age and PAH content has been observed.     

Polycyclic aromatic hydrocarbons in soil and plant samples from the vicinity of an oil refinery

Soil samples, and samples of leaves of Plantago major (great plantain) and grass (mixed species) were collected from the vicinity of an oil refinery in Zelzate, Belgium, and analysed for seven polycyclic aromatic hydrocarbons (PAHs). The samples from the site adjacent to the refinery (site 1) contained very high total PAH-concentrations: namely 300, 8 and 2 microg/g dry wt. for soil, P. major and grass, respectively. Concentrations in samples from more remote sites (up to 4 km from the refinery) were a factor of 10-30 lower than those from site 1, but between them the differences were small. The PAH-profiles of the plant samples, in contrast with those of the soil samples, appeared to shift to higher contributions of gaseous PAHs with increasing distance from the refinery. This can be explained by particle-bound PAHs being deposited closer to the source than gaseous PAHs. It is suggested that particle-bound deposition is relatively more important for deposition to soil than to plants, due to blow-off and wash-off of the compounds from the leaves. The total PAH-concentrations in the leaves of P. major were higher than those measured in the grass samples, probably due to differences in aerodynamic surface roughness, leaf orientation and/or leaf age. However, the concentration ratios of P. major/grass were not constant for the different sites, varying from 1.2 to 8.8. Therefore, it appears that a precise prediction of PAH-concentrations for one plant species from known concentrations of another species is not possible. When errors in predicted concentrations need to be smaller than a factor of approximately 10, the sampling strategy has to be focussed on all species of interest.     

Poly-chlorinated biphenyls,poly-chlorinated naphthalenes and polynuclear aromatic hydrocarbons in severn estuary (U.K.) sediments

Sediments taken from the upper part of the Severn Estuary have been extracted by cyclic steam distillation into hexane. Analysis of the extract revealed a variety of organic pollutants including alkanes and several poly-nuclear aromatic hydrocarbons (PNA's). A PCB residue was detected and quantified using the technique of carbon-skeleton gas chromatography employing a 3% palladium catalyst and 2% RbCl salt column. The level of PCB in the sediments was found to be of the order of 1 ppm. No significant levels of poly-chlorinated napthalene (PCN) or DDT and related species were found.Organic contamination of one sediment (Arlingham) was found to be associated with the coal particles present in the sample. Levels of contamination at Arlingham were thus shown to be a function of sample composition rather than of the geographical location of the site.