Concentrations Of Polynuclear Aromatic Hydrocarbons Research Articles

Survival in air of Mytilus trossulus following long-term exposure to spilled Exxon Valdez crude oil in Prince William sound

Mussels, Mytilus trossulus, were sampled in 1996 from beaches in Prince William Sound (PWS) which contained residual oil resulting from the Exxon Valdez oil spill of March 1989, and from one beach which had been lightly oiled in 1989, but contained no residual oil in 1996. The latter mussels served as un-oiled references. Mussels were also collected from Tee Harbor, Southeast Alaska, to be used as an additional reference group. Where the size of the individuals in the resident population would permit, two size groups were sampled, 32–35 and 18–20 mm in length. Polynuclear aromatic hydrocarbon (PAH) concentrations in mussel tissue, and air survival time were determined for each group of mussels. Total PAH concentrations were significantly greater in tissue of mussels from oiled beds (0.6–2.0 μg g −1) than from references (0.01–0.12 μg g −1) ( P<0.01). Oil-exposed mussels had significantly lower LT 50 values ( P<0.05) for air survival than reference groups. Tolerance of small mussels to air exposure was significantly greater ( P<0.01) than large mussels in both the unoiled reference and oil exposed groups.

Lack of physiological responses to hydrocarbon accumulation by Mytilus trossulus after 3–4 years chronic exposure to spilled Exxon Valdez crude oil in Prince William Sound

Mussels, Mytilus trossulus, were sampled in 1992 and 1993 from beaches in Prince William Sound that had been oiled by the Exxon Valdez spill of March, 1989. At some of the oiled beaches, mussels were collected from beds overlying oiled sediments, and from bedrock adjacent to these beds. Mussels were also collected from beaches within the Sound that had not been impacted by the spill. Polynuclear aromatic hydrocarbon (PAH) concentrations in mussel tissue, physiological responses (byssal thread production, condition index, clearance rate, and glycogen content), were determined for each group of mussels. Total PAH concentrations in mussel tissue ranged from 0 to 6 μg g −1, and were significantly greater in mussels from oiled beds than those from reference beds. No significant differences were noted in byssal thread production, condition index, clearance rate, or glycogen content between oiled sample sites and reference sites. The lack of physiological response was surprising because mussels in this study were chronically exposed to PAH for 3–4 years, and none of the physiological responses measured appeared to be affected by that exposure. The lack of a physiological response suggests that chronically exposed mussels may develop a physiological tolerance to PAH, but we recognize that these measures may not have been sensitive enough to discriminate response from background noise.

Determining organic compound ratios in soils and vegetation of the Holy Cross Mts, Poland

The objectives of this investigation in the Holy Cross Mountain region of Poland were (1) to establish organic-concentration baselines, and (2) (if possible) to determine spatial distribution pattern of polynuclear aromatic hydrocarbons in topsoil. These objections were accomplished using an unbalanced, nested analysis-of-variance (ANOVA) barbell sampling design. Samples of topsoil (horizon A), Scots pine (Pinus sylvestrisL.) needles and lichen thalii Hypogymnia physodes(L.) Nyl. were collected for polynuclear aromatic hydrocarbons (PAHs), polychlorinatedbiphenyls (PCBs), organochlorine pesticides and phenols. Of these four organic groups, PAHs was detected in topsoil of nearly all investigation sites. Their total content ranged from 4.43 to 1905.83 gk g 1 , exceeding at some places that assessed for unpolluted cultivated soils of Poland. The results of organic compound determinations performed on soils and vegetation from the Holy Cross Mountain region showed that some concentrations of compounds were elevated probably due to air pollution. Nonetheless, some portions of them, especially phenols, might have been products of metabolic activity. Topsoil, Scots pine and partly lichens of Eysica Mt. revealed the highest concentrations of PAHs, PCBs and organochlorine pesticides. The content of PCBs in lichens of the study region was somewhat higher than in Lapland.

Adduct distributions in piscine DNA: South-Eastern black sea

The south-eastern Black Sea is relatively unpolluted and contains polynuclear aromatic hydrocarbons (PAHs) only of the order of 1 μg 1 −1. Pelagic and benthic fish were monitored during three successive winters from 1993 to 1996 for PAHs and for DNA adducts. The fish caught ( Mugil sp., Mullus barbatus, Alosa fallax, Merlangius merlangus, Sprattus sprattus and Platichthys flesus) varied annually in length, weight and species composition. Although their livers were oily and contained significant concentrations of PAHs (11–56 μg g −1), 32P-postlabelling relatively low levels of hydrophobic DNA .adducts (3–20 per 10 8 nucleotides) in either fish livers or blood. A significant fraction of the DNA adducts in the blood samples, unlike those in the livers, were dephosphorylated by nuclease-P1.

Studies Estimating the Dermal Bioavailability of Polynuclear Aromatic Hydrocarbons from Manufactured Gas Plant Tar-Contaminated Soils

In vitro percutaneous absorption studies were performed with contaminated soils or organic extracts of contaminated soils collected at manufactured gas plant (MGP) sites. The MGP tar contaminated soils were found to contain a group of targeted polynuclear aromatic hydrocarbons (PAH) at levels ranging from 10 to 2400 mg/kg. The soil extracts contained target PAH at levels ranging from 12 000−34 000 mg/kg. Dermal penetration rates of target PAH from the MGP tar-contaminated soils/soil extracts were determined experimentally through human skin using 3H-benzo[a]pyrene (BaP) as a surrogate. Results from three MGP sites showed reductions of 2−3 orders of magnitude in PAH absorption through human skin from the most contaminated soils in comparison to the soil extracts. Reduction in PAH penetration can be attributed to PAH concentration and (soil) matrix properties. PAH dermal flux values are used to determine site-specific dermally absorbed dose (DAD) and chronic daily intake (CDI) which are essential terms required to estimate risk associated with human exposure to MGP tar and MGP tar-contaminated soils.

Potential of Phytoremediation for Treatment of PAHs in Soil at MGP Sites

Phytoremediation is a natural, aesthetically pleasing, low-cost technology that employs plant-influenced microbial, chemical, and physical processes to remediate contaminated soils and waters. The Institute of Gas Technology (IGT) conducted a laboratory study to determine the potential of phytoremediation to remediate soils contaminated with polynuclear aromatic hydrocarbons (PAHs). The soils used for the study were collected from a former manufactured gas plant (MGP) site in Newark, NJ. Phytoremediation was assessed both as a primary remediation technology and as a final polishing step for soil treatment. The following three plant species were used for the 6-month laboratory study: alfalfa (Medicago sativa), switch grass (Panicum virgatum), and little bluestem grass (Schizachyrium scoparium). Using both alfalfa and switch grass for primary treatment of PAH-contaminated soil, a 57% reduction in total PAH concentration was observed after 6-months of treatment. Final polishing of that soil using alfalfa further reduced the total PAH concentration in that soil by 15%. Research is in progress with the objective of improving both the efficiency and the economics of phytoremediation for the cleanup of contaminated soils to environmentally acceptable endpoints at MGP sites.

Sister chromatid exchange induction in peripheral blood lymphocytes of traffic police workers

Traffic police workers, as a population exposed to urban atmosphere, were compared with a control population exposed to indoor air pollution levels. Sister chromatid exchanges (SCEs) as a biomarker of effect were measured in peripheral blood lymphocytes of 54 exposed subjects and 35 controls, and environmental concentration of polynuclear aromatic hydrocarbon (PAH) tracer compounds was detected by personal air samplers. The mean exposure level to benzo[ a]pyrene in our group of traffic policemen (3.4 mg/m 3) was in the range that has been estimated in urban areas in Europe during the last 10 years. No difference in SCE levels was found between exposed workers (7.36, SD 1.35) and controls (7.47, SD 1.28). No correlation was observed between SCE/cell and airborne PAH concentration in the traffic worker population. A positive regression of SCE on exposure estimate was found only in the non-smoking group of police workers. Our findings suggest that exposure to urban air pollution does not induce relevant cytogenetic effects.

PAHs in soils: contemporary UK data and evidence for potential contamination problems caused by exposure of samples to laboratory air

Archived (1951–1974) and contemporary (1993) surface soil samples collected from the same 46 locations widely distributed over the UK have been analyzed for 12 polynuclear aromatic hydrocarbons (PAHs). Contemporary soils were analyzed wet, ensuring that contamination, losses or alteration of PAHs in the samples was minimal. Archived soils had been air-dried prior to storage. The ΣPAH concentration of the contemporary and archived soils range from approx. 20 μg kg −1 to 7.4 mg kg −1 (mean = 1.1 mg kg −1) and from approx. 160 μg kg −1 to 7.1 mg kg −1 (mean = 2.1 mg kg −1), respectively. Comparison of the concentrations of PAHs in the archived and contempcrary soils revealed no significant trends for compounds heavier than benzanthracene. For some of the lighter molecular weight compounds the concentrations were notably higher in the archived soils than in the contemporary soils. Two soils of contrasting PAH content (0.08 and 9.8 mg kg −1) were used in an experiment to compare the effects of air-drying on soils with relatively low and high PAH concentrations. Subsamples of soil (10 g) were placed into foil trays and exposed to laboratory air for up to 64 days. A clear increase in theiconcentration of the lighter molecular weight compounds (acenaphthene, fluorene, phenanthrene) occurred in both soils. No marked changes were observed for the heavier molecular weight PAH compounds. This experiment suggests that the higher concentrations of the lower molecular weight compounds measured in the archived soil samples is due to contamination during air drying.

Identification ofExxon ValdezOil in Sediments and Tissues from Prince William Sound and the Northwestern Gulf of Alaska Based on a PAH Weathering Model

We used a first-order loss-rate kinetic model of polynuclear aromatic hydrocarbon (PAH) weathering to evaluate 7767 environmental samples collected for the Exxon Valdez oil spill (EVOS) for the presence of spilled oil. The model was developed from experiments with gravel coated with crude oil and washed for 6 months. The modeled PAH included the 14 most persistent compounds of 31 analyzed by GC/MS. Parameters include loss-rate constants related to the energy required for PAH to escape from petroleum and a quantitative index of weathering. The model accounts for 91% of the temporal variability of modeled PAH concentra tions. We compared the discrepancies between measured and model-predicted PAH concentrations of EVOS samples with a probability distribution of these dis crepancies derived from the experimental weathering results. Only 1541 field samples contained sufficient PAH for valid application of the model; three-fourths fit the model at α ≥ 0.01 type I error, 9% fit an alternate model characterized b...

Effects of diesel fuel composition on SOF and PAH exhaust emissions

Experiments were performed with a six cylinder test engine using both ordinary diesel fuel and synthetic diesel fuel, which has simple hydrocarbon components and no aromatics or sulfur content. SOF is extracted from the particulate sample, then GC and GC-MS analyses were carried out. By comparing the results obtained, the role of high boiling point components in diesel fuel on SOF emission was observed. Further, by adding an artificial sulfur-containing compound and pyrene, which is a four ring polynuclear-aromatic-hydrocarbon (PAH), into the synthetic fuel, the effect of PAH content in fuel on PAH emission in SOF and the increase of SOF with increased sulfur content in fuel, were observed.

Ascites, premature emergence, increased gonadal cell apoptosis, and cytochrome P4501A induction in pink salmon larvae continuously exposed to oil-contaminated gravel during development

Development of pink salmon (Oncorhynchus gorbuscha) incubating in gravel contaminated with weathered Prudhoe Bay crude oil was retarded at concentrations as low as 55.2 μg oil/g gravel. Larvae exposed to various levels of oil contamination were sampled 4 weeks before emergence, at emergence, and 13 days after emergence for histopathology (quantitative and semiquantitative) and cytochrome P4501A (CYP1A) induction (using immunohistochemical staining). A subset of postemergent fish was not fed. Hydrocarbon analysis by gas chromatography and mass spectroscopy revealed that tissue uptake of polynuclear aromatic hydrocarbons (PAH) was mediated by oil's dissolution in water, with significant biological effects when the peak total PAH concentration in water was as low as 4.4 μg/L. Oil-related effects included induction of CYP1A, development of ascites, and increased mortality. Several oil-related changes were indicative of premature emergence. Compared with control fish, for example, exposed fish of the same age and emerging on the same day had greater amounts of yolk and hepatocellular glycogen, increased apoptosis of gonadal cells and midventral skin cells, and less food in the gastrointestinal tract. Histological features were similar within groups of larvae sampled 4 weeks before and 13 days after emergence, and oil-induced changes were not affected by feeding during the first 13 days after emergence. Increased gonadal cell apoptosis may be related to later reproductive impairment documented in field studies of pink salmon up to 4 years after the Exxon Valdez oil spill.

Baseline studies in the Slave River, NWT, 1990–1994: Part I. Evaluation of the chemical quality of water and suspended sediment from the Slave River (NWT)

The Slave River watershed at the Alberta-Northwest Territories border drains a large area and is the recipient of chemical compounds from a variety of aquatic sources, including the Athabasca and Peace Rivers. The potential for contamination from industrial and agricultural processes upstream is very real. Thus, the Slave River Environmental Quality Monitoring Program was established in 1990 to assess the water and suspended sediment quality in the territorial portion of the river. A baseline data set with which to determine present and future effects from upstream activities and long-range transport of contaminants was created. The number of ‘above detect’ data points from measurements of polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and chlorinated phenolics (CPs) in water was small and those concentrations of compounds that were above analytical detection limits were very low and unlikely to have adverse effects on the ecosystem. No pesticide levels were ever detected in the water during the 5-year monitoring period, even though long-range transport of these contaminants to the Arctic have been well-documented. Levels of metals were often observed in measurable concentrations in the Slave River water, and frequently exceeded water quality guidelines, although not by any substantial amount. It was concluded that although the concentrations were relatively high, the metals are probably occurring naturally, and not from upstream industrial sources. It was speculated that aquatic biota had probably adapted to these levels. Although PAH concentrations in suspended sediment from the Slave River at Fort Smith often exceeded the ‘Lowest Effect Level’ guideline established in bottom sediment by the Ontario Ministry of the Environment, values remained well below the ‘Severe Effect Level’. Conclusions were reached that PAH concentrations in Slave River suspended sediment were not substantial enough to cause a threat to the ecosystem. Metal levels in suspended sediment remained variable over the 5-year monitoring period and no trends could be seen regarding an overall increase or decrease in concentrations. The low number of ‘above detect’ data points for pesticides and chlorinated phenolics observed in the suspended sediment during the program suggested that adverse impacts would not be occurring from these contaminants in the watershed. Lastly, although certain concentrations of dioxins and furans were measured and were often higher than levels observed in the Wapiti/Smoky River system and the Athabasca River, the values were very small and the contributing homologues had a minimal toxic potential. Detectable levels of 2,3,7,8-TCDD were never observed in the suspended sediment in the Slave River at Fort Smith. Sediment elutriate tests over a 48 h period using Dophnia magna and Photobacterium phosphoreum (Microtox) indicated little acute toxicity. These results seem plausible, given that chemical concentrations of contaminants in the suspended sediment were generally very low or below analytical detection. It can be concluded from the extensive data set collected during the 5-year program that impact from upstream industrial and agricultural sources is, at the present time, negligible, and that the environmental quality of the Slave River at Fort Smith is pristine. Also, the extensive data set has established a baseline, which can be used for future comparative purposes.

Aromatic Hydrocarbons in Biota from the Detroit River and Western Lake Erie

Polynuclear aromatic hydrocarbons (PAHs) and PCBs in zebra mussels were elevated to concentrations greater than 5,000 ng/g lipid and 15,000 ng/g lipid, respectively, at the Ambassador Bridge in the Detroit River and concentrations gradually declined at downstream locations, which included three stations in the western basin of Lake Erie (Middle Sister Island, East Sister Island, Pelee Island). PCB concentrations in zebra mussels collected at the stations in western Lake Erie were elevated relative to the concentrations in mussels at the upstream end of the Detroit River (Stoney Point). There is no evidence that PAH contamination in the Detroit River elevated PAH concentrations in zebra mussels in western Lake Erie relative to mussels at Stoney Point. Fluorescent aromatic compounds (FACs) representing metabolites of PAHs were analyzed in the bile of gizzard shad ( Dorosoma cepedianum) and freshwater drum ( Aplodinotus grunniens) collected from several sites in the Detroit River and western Lake Erie. Mean FAC concentrations were >l,000 ng BaP equivalents per mL of bile in fish from the Trenton Channel and Boblo Island in the Detroit River, but FAC data provided no evidence that fish captured at two sites in western Lake Erie (East Sister Island, Pelee Island) were exposed to elevated concentrations of PAHs through ingestion of contaminated biota or exposure to contaminated sediments.

On polynuclear aromatic hydrocarbons contamination levels in the ecosystem of Lake Peipsi in the 1970s?1980s

The data on benzo(a)pyrene (BaP) and other polynuclear aromatic hydrocarbons (PAH) pollution of Lake Peipsi and its tributaries in the 1970s–1980s have been summarized. Systematic data on the pollution of Lake Peipsi by BaP are available. The BaP content in lake water varied from <0.1 to 237 ng 1−1. The content and qualitative composition of PAH varied in different observations. PAH were accumulated mainly in the bottom sediments; in their surface layer BaP concentrations were 103–106 times higher than in water. The concentration of the PAH in bottom sediments varied from 16 to 580 µg kg−1 in the lake and from 40 to 2800 µg kg−1 in its tributaries. The content of BaP in fish and biota was not high. Among the pollution sources the atmospheric pollution played quite a significant role. The lake was also polluted by oil spillage and fuel exhausts from boats and ships. The PAH concentration in the water of the tributaries was somewhat higher than in the area of Lake Peipsi.

Wood preservative leachates from docks in an estuarine environment

Environmental concentrations and biological effects of certain metals and organic compounds found in wood preservatives were examined. The study focused on leachates from private residential docks in South Carolina tidal creeks. Copper, chromium, arsenic, and polynuclear aromatic hydrocarbons (PAHs) were measured in composite samples of surficial sediments and naturally occurring oyster populations (Crassostrea virginica) from creeks with high densities of docks, and from nearby reference creeks with no docks. In some cases, metal concentrations in sediments and oysters were higher immediately adjacent to dock pilings than they were elsewhere in the same creek. Sediments from most sites had concentrations of metals and total PAHs which were below levels reported to cause biological effects, however. Solid-phase Microtox(R) bioassays using whole sediments and rotifer bioassays using sediment pore water showed no significant differences in acute toxicity between creeks with and without docks. Oysters growing directly on dock pilings had significantly higher concentrations of copper than oysters growing at least 10 m away; however, there was no significant difference in the physiological condition of these oysters. Four-day field bioassays measuring percent survival of mummichogs (Fundulus heteroclitus), mud snails (Ilyanassa obsoleta), juvenile red drum (Sciaenops ocellatus), and juvenile white shrimp (Penaeus setiferus) showed no significant differences between sites near to and distant from newly constructed docks. Hatchery-reared oysters showed no significant differences between dock and reference sites in percent survival, growth, or bioaccumulation of metals after six weeks of exposure. The results suggest that, in estuarine environments with a moderate tidal range (1.5-2.0 m), wood preservative leachates from dock pilings have no acutely toxic effects on four common estuarine species, nor do they affect the short-term survival or growth of juvenile oysters.

Evaluation of extraction and detection methods for determining polynuclear aromatic hydrocarbons from coal tar contaminated soils

The use of batch, Soxhlet, and sonication extraction techniques was evaluated for determining the concentration of polynuclear aromatic hydrocarbons (PAHs) in four soils contaminated with coal tar. Chromatographic analysis of eighteen PAHs was performed using both ion trap detector (ITD) and flame ionization detector (FID). No consistent differences were observed between the three extraction methods or between the two different chromatographic detection systems. The batch extraction technique was considered the least labor intensive and most cost effective method. The use of GC/FID with certified calibration standards was also found adequate for routine analysis of known organic compounds.

A study of interactions between soil fractions and PAH compounds in thermal desorption of contaminated soils

AbstractThe interactions between three polynuclear aromatic hydrocarbons (PAHs), namely fluorene, naphthalene and anthracene, and three fractions of a soil, namely fulvic acid (FA), humic acid (HA) and humin/inorganic fractions, were studied experimentally. Prepared PAH + soil fraction binary mixtures, with PAH concentrations ranging over 0.8–7 mass%, were tested using a differential scanning calorimeter (DSC) over a temperature range of 20−390°C. The DSC thermograms for the PAH + HA mixtures showed distinctly different characteristics compared to mixtures with the other two soil fractions, where the endothermic peak for the vaporization of the PAH was absent. With the aid of vapour‐liquid flash calculations, the lack of the boiling point peak is interpreted to be due to the liquid‐phase miscibility of the PAHs and the HA fraction. Implications of the DSC results on the design and performance of the thermal desorption process are discussed.

Industrial organic compounds in selected Canadian soils

Studies were conducted to determine the concentrations of a large number of industrial organic compounds in selected Canadian agricultural soils and to assess the potential for land application of municipal sludges to cause significant polynuclear aromatic hydrocarbon (PAH), organochlorine pesticide (OC) and polychlorinated biphenyl (PCB) contamination of agricultural land. Twenty-four Agriculture and Agri-Food Canada, Soil Quality Evaluation Program (SQEP) benchmark soils and six intensively cropped southern Ontario soils exhibited similar small concentrations of a few base-neutral and acid (BN&amp;A) extractable industrial organic compounds (seldom &gt;1 mg kg−1 dry wt), PCBs (&lt;200 μg kg−1 dry wt) and organophosphorus pesticides (OPs). Fonofos, the only OP detected, was observed at concentrations &lt;100 μg kg−1 dry wt. Neutral and phenoxy acid herbicide analyses for 13 soils (seven SQEP and six intensively cropped) indicated infrequent detection of these compounds. There was no detection of carbamate herbicides. In most soils, only trace amounts (&lt;10 μg kg−1 dry wt) of OCs were observed but in one intensively cropped soil, DDT exceeded 70 mg kg−1 dw. A greater incidence of compounds such as alpha chlordane, dieldrin, aldrin and DDT in intensively cropped than in other soils is assumed to reflect increased use of these compounds for intensive crop production. Soils treated with sludge according to recommended practice exhibited minor increases in PAH, OC and PCB concentrations. There is no risk to human health or the environment from industrial organic conpounds, except possibly DDT, in Canadian agricultural soils that have received no sludge or from PAHs, OCs and PCBs in soils that have received southern Ontario sludges according to recommended practice. Key words: Municipal sludge, industrial organic compounds, organic contaminants, agricultural sustainability, soil

Assessing aromatic hydrocarbon exposure in Antarctic fish captured near palmer and McMurdo Stations, Antarctica

Since little is known about the effects of contaminants on Antarctic organisms, the effects of polynuclear aromatic hydrocarbons (PAH) on Antarctic fish were evaluated. Fish captured near Palmer Station on the Antarctic Peninsula exhibited induced ethoxyresorufin O-deethylase (EROD) activities and elevated concentrations of biliary PAH metabolites compared to fish from control sites. Naphthalene and phenanthrene PAH metabolite levels were significantly higher in the bile of fish captured near McMurdo Station than in fish from remote sites in McMurdo Sound. Laboratory experiments were conducted in which Notothenia gibberifrons were treated with benzo[a]pyrene (BaP) and diesel fuel Arctic (DFA). Although DFA is composed primarily of 2- and 3-ring PAH which are not known to be potent CYPIA inducers, the maximal hepatic EROD activity of DFA-treated fish was approximately 80% of that observed in BaP-treated fish. Additionally, 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) were determined for hepatic extracts of laboratory-dosed and field-captured fish using rat hepatoma H4IIE cell bioassays. The TEQ values of H4IIE cells dosed with hepatic extracts of DFA-treated fish correlated more closely with hepatic concentrations of 3-ring and >3-ring PAH than with 2-ring and ΣPAH concentrations. However, bioassay-derived TEQs were higher than expected based on the measured levels of ≥3-ring PAH in the hepatic extracts of DFA-treated fish. The TEQs for hepatic tissue extracts of BaP-treated fish paralleled tissue concentrations of PAH. The TEQs for field captured fish were significantly lower than those derived from dosed fish extracts.

Organic Micropollutants in Swiss Agriculture: Distribution of Polynuclear Aromatic Hydrocarbons (PAH) and Polychlorinated Biphenyls (PCB) in Soil, Liquid Manure, Sewage Sludge and Compost Samples; a Comparative Study

Abstract This report aims to give a general view of the present state of contamination of agricultural soils and manures like sewage sludge, liquid manure and compost in Switzerland with two groups of organic micropollutants: polynuclear aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB). Overall PAH concentrations for soils ranged between 60–575 μg [sgrave] PAH/kg dw (mean value 175 μg/kg dw). The corresponding values for the other matrices were: cattle slurries 87–309 μg/kg (165 μg/kg), pig slurries 66–339 μg/kg (143 μg/kg), sewage sludge 1.7–15 mg/kg (6.3 mg/kg) and compost 0.8–2.7 mg/kg (2 mg/kg). PCB levels for soils averaged 14 μg [sgrave] PCB/kg dw and represented typical background concentrations. PCB values in cattle slurries were slightly higher (20 μg/kg) and significantly higher in pig slurries and compost (37 and 32 μg/kg). The highest PCB concentrations were found in sewage sludges (0.4 mg/kg). Application of these sludges onto soils at rates normally used in Switzerland (0.5 to...