Kristoffer Næs

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 (PAHs) in Sediments of the White Sea, Russia

The extent of environmental contamination and sources of polycyclic aromatic hydrocarbon (PAH) compounds to sediments of the White Sea are evaluated and compared with previously published results for adjacent Arctic Sea areas. Concentrations of two- to six-ring PAHs of molecular mass 128–278 including perylene and sediment characteristics are considered in this investigation. Mean ΣPAH concentration was 61±34 ng/g dw (n=11) for all samples and 87±43 ng/g dw (n=6) for pelite-rich samples (>83% pelite). These concentrations are 2–3 times lower than were previously reported for the SE Barents Sea. Concentrations of ΣPAH and ΣCPAH in the central White Sea have increased by a factor of 2-5 over pre-industrial background levels based on 210Pb age-dating of one sediment core. Using principal component analysis (PCA), two common factors explained 87.5% of the total variance for the White Sea data. Factor 1 is associated with high-temperature combustion processes and is related to emissions from a local aluminium smelter. Factor 2 is associated mainly with the introduction of petrogenic PAH compounds and perylene into Dvina Bay via the Severnaya Dvina River. A comparison of the White Sea and SE Barents Sea data indicates that similarities exist in the composition of parent PAH compounds. However, based on a comparative analysis of parent PAH ratios and relative contents of alkyl-substituted homologues, a common atmospheric source of anthropogenic pollutants can be ruled out. Further investigations are needed to determine whether sedimentary PAH signatures in areas of the Barents Sea that are in closer proximity to the White Sea are related to emissions from the aluminium smelter.

Bioaccumulation of native polycyclic aromatic hydrocarbons from sediment by a polychaete and a gastropod: freely dissolved concentrations and activated carbon amendment.

The present paper describes a study on the bioaccumulation of native polycyclic aromatic hydrocarbons (PAHs) from three harbors in Norway using the polychaete Nereis diversicolor and the gastropod Hinia reticulata. First, biota-sediment accumulation factors (BSAFs) were measured in laboratory bioassays using the original sediments. Median BSAFs were 0.004 to 0.01 kg organic carbon/kg lipid (10 PAHs and 6 organism-sediment combinations), which was a factor of 89 to 240 below the theoretical BSAF based on total sediment contents (which is approximately one). However, if BSAFs were calculated on the basis of measured freely dissolved PAH concentrations in the pore water (measured with polyoxymethylene passive samplers), it appeared that these BSAFfree values agreed well with the measured BSAFs, within a factor of 1.7 to 4.3 (median values for 10 PAHs and six organism-sediment combinations). This means that for bioaccumulation, freely dissolved pore-water concentrations appear to be a much better measure than total sediment contents. Second, we tested the effect of 2% (of sediment dry wt) activated carbon (AC) amendments on BSAE The BSAFs were significantly reduced by a factor of six to seven for N. diversicolor in two sediments (i.e., two of six organism-sediment combinations), whereas no significant reduction was observed for H. reticulata. This implies that either site-specific evaluations of AC amendment are necessary, using several site-relevant benthic organisms, or that the physiology of H. reticulata caused artifactually high BSAF values in the presence of AC.

Occurrence of PAH in marine organisms and sediments from smelter discharge in Norway

Norwegian aluminium works have each discharged 1–10 tons or more of PAH per annum directly into fjords, most of which originates from the scrubbing of hall gas in connection with Soderberg technology and from the production of anodes. In recent years, discharges have been considerably reduced, but still > 10 tons per year are discharged from the industry. Environmental assessment studies have systematically been performed from about 1980. Analyses of indicator organisms which accumulate PAH in high concentrations without apparent detrimental effects, have been used to assess the extent of contamination of water masses. The blue mussel (Mytilus edulis), and also its close relative the horse mussel (Modiolus modiolus), appear to be the most important indicators. The large amounts of waste have resulted in considerable contamination of fjord biota and sediments. PAH concentrations in indicator organisms of > 1000 times the background values have been recorded within 1–2 km of the outfalls. Elevated concentrations have been traced for more than 35–40 km. Surface sediment concentrations in the range of some hundred μg total PAH/g dry wt. have been observed. The concentration gradients vary but are generally steep. In several receiving waters, considerable improvements have been recorded shortly after a reduction in output load, and concentrations in mussels have fallen to 1100 of previous values in some cases. Remobilization experiments indicate that ‘hot spot’ accumulations might be of significance.

Multivariate approach to distribution patterns and fate of polycyclic aromatic hydrocarbons in sediments from smelter-affected Norwegian fjords and coastal waters

The environmental significance of polycyclic aromatic hydrocarbons (PAHs) generated by the production of aluminum and manganese alloys is an important issue in numerous Norwegian fjords. The fate of these compounds have been elucidated by analyzing surface and subsurface sediment samples collected over a 15-year period from seven smelter-affected fjords applying principal component analysis (PCA). Consistent patterns within and between fjords and between production types suggested causal relationships and formed the basis for formulating hypotheses regarding the fate of the compounds. The PCA was able to dif ferentiate between various combustion origins at receptor locations, so far hidden in the traditional treatment of the data restricted to individual fjords. This differentiation reflected industrial processes and most probably cleaning arrange ments at the different plants. The source-specific signals were discernible over considerable distances and down to concentrations 3-4 times background levels. Compound-specific transformation reactions occurring during transport and incorporation into the sediments contributed little to the total variance and did not suppress the source-specific signals. This may imply a rather low availability to the bottom fauna and raise questions as to the potential harm inflicted by smelter-generated PAHs.

Bottom trawling resuspends sediment and releases bioavailable contaminants in a polluted fjord

Sediments are sinks for contaminants in the worlds oceans. At the same time, commercial bottom trawling is estimated to affect around 15 million km(2) of the worlds seafloor every year. However, few studies have investigated whether this disturbance remobilises sediment-associated contaminants and, if so, whether these are bioavailable to aquatic organisms. This field study in a trawled contaminated Norwegian fjord showed that a single 1.8 km long trawl pass created a 3-5 million m(3) sediment plume containing around 9 t contaminated sediment; ie. 200 g dw m(-2) trawled, equivalent to c. 10% of the annual gross sedimentation rate. Substantial amounts of PCDD/Fs and non-ortho PCBs were released from the sediments, likely causing a semi-permanent contaminated sediment suspension in the bottom waters. PCDD/Fs from the sediments were also taken up by mussels which, during one month, accumulated them to levels above the EU maximum advised concentration for human consumption.

The distribution and environmental relationships of polycyclic aromatic hydrocarbons (PAHs) in sediments from Norwegian smelter-affected fjords

PAH distribution was examined in 119 surface sediment samples collected in connection with monitoring surveys in four Norwegian fjords affected by aluminium and manganese alloy smelters. Regression, principal component analysis (PCA) and redundancy analysis (RDA) were used to identify common patterns and possible correlations with explanatory variables (distance, depth, grain size, TOC, C/N-ratio, metals). The best-fitting variables corresponded to the deposition of PAH, expressed either as a function of distance from source or as the amount of PAH-bearing material. This supports the assumption that particulate, combustion-derived PAHs are resistant to transformation during transport and incorporation into surface sediments. Compound-specific processes leading to minor, but systematic and strikingly similar profile variations in the fjords could not be adequately explained by the environmental variables.

Accumulation and effects of aluminum smelter-generated polycyclic aromatic hydrocarbons on soft-bottom invertebrates and fish

An integrated study involving measurements of polycyclic aromatic hydrocarbon (PAH) levels in bottom sediments, assessments of resident soft-bottom communities, the accumulation of PAHs in soft-bottom invertebrates, and biomarker responses in invertebrates and fish was conducted to assess the impact of an aluminum reduction plant in a Norwegian fjord. The fjord sediments were heavily contaminated by PAHs in the inner reaches near the aluminum smelter, where concentrations were well above levels elsewhere reported to induce biological effects. Nevertheless, the PAH contamination in the fjord did not seem to have severe effects on the benthic biota. This conclusion can be drawn from the soft-bottom communities as well as from biomarker analyses. Presumably, contaminant speciation is important for explaining the restricted biological effects. The results support the assumption that PAHs associated with soot-like structures have limited bioavailability. They also point to the need to link various single-species approaches to measurements of effects on higher levels of organization and with an understanding of the speciation of the chemical contaminant.

Effects-Directed Analysis of Sediments From Polluted Marine Sites in Norway

The environmental status of two polluted marine sites in Norway was investigated by a combination of target chemical analysis and effect-directed analysis (EDA). The two selected sites, the Grenland area and Oslo harbor, in addition to two reference sites, were classified according to the Norwegian environmental classification system based upon results of the target chemical analyses. The polluted sites were characterized by high levels of metals, polycyclic aromatic hydrocarbons (PAH), and polychlorinated biphenyls (PCB). High levels of organotin compounds were also detected in Oslo harbor. The aryl hydrocarbon receptor (AhR) agonist activity in extracts of sediments from marine sites close to Oslo, Oslo harbor, and Grenland were investigated using the CALUX (chemical-activated luciferase expression) assay, which showed elevated levels of activity. As expected from the history of dioxin release into the Grenland area, the results were highest in this area. The presence of estrogen receptor (ER) and androgen receptor (AR) antagonists was also detected in the sediment extracts. Following fractionation of the sediment extracts, EDA was used to tentatively identify the AhR agonists. The compounds responsible for AhR agonist activity in samples from Oslo harbor were isolated in fraction 13, and to a lesser extent in fractions 9–11. In Grenland, the main activity was found in the more polar fractions, namely fractions 14–18. The AhR agonists identified in Oslo harbor were mainly PAH, while in the Grenland area the compounds identified were mainly nitrogen/oxygen-containing polyaromatic compounds (N/O-PAC).

Total particulate and organic fluxes in anoxic Framvaren waters

Abstract Cylindrical sediment traps were deployed at various depths in the anoxic water of Framvaren for two periods of one year (1981–1982 and 1983–1984). The traps were emptied three times during 1981–1982 and five times during 1983–1984. The vertical fluxes of total suspended material, organic carbon and nitrogen were calculated on a daily and annual basis. The average annual sediment flux 20 m above the bottom was approximately 60 g m −2 y −1 and the flux of organic carbon was 20 g m −2 y −1 . On the basis of an average C/N ratio of 8 and a constant carbon flux below a depth of 20 m, it is concluded that little mineralization of the organic matter takes place in the anoxic water column. Assuming a primary production of the order to 50–100 g m −2 y −1 , 22–24% of that reaches the anoxic water masses. Further breakdown of organic matter takes place in the surface sediments.