The distribution and relative toxic potential of organic chemicals in a PCB contaminated bay

For reliable monitoring of environmental improvement, the PCB contaminated bay Orserumsviken on Sweden's Baltic coast was investigated prior to remediation. We examined PCB congener patterns and the relative toxic potential of PCBs in extracts of three matrices: bottom sediment, settling particulate matter and the dissolved phase (obtained from semi-permeable membrane devices). Congener patterns were similar in all matrices. Three fractions were isolated from the extracts: (1) aliphatic and monocyclic aromatic compounds (MAC-fraction), (2) dicyclic aromatic compounds (DAC-fraction), including PCBs, and (3) polycyclic aromatic compounds (PAC-fraction), including PAHs. Total extracts and fractions were injected into newly fertilised rainbow trout eggs. At larval stage, hepatic EROD activities were quantified. Though high, the PCB contamination could explain only an estimated 1-5% of the total EROD induction. The order of EROD induction potential was: total extract > PAC-fraction > DAC-fraction > MAC-fraction in all matrices, suggesting that in Orserumsviken PACs made a larger contribution to the EROD induction potential than PCBs and other DACs.     

Biotransformation enzyme activities and PCDD/PCDF levels in pike caught in a Swedish Lake

Recently, analysis of organochlorines in sediment and in pike from Lake Vänern, Sweden, showed a north-south gradient of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). In the present study, good correlations were found between muscle 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents and liver ethoxyresorufin-O-deethylase (EROD) activities (and P4501A levels) in pike caught at three sampling sites along the north-south gradient in the lake. This comparison between tissue levels of PCDD/PCDF and EROD activity (and P4501A) may indicate that TCDD or structural analogs could be responsible for the observed induction of the pike P450 system. It must, however, be taken into account that the analysed contaminants often do not appear alone but are, rather, accompanied by a range of other substances which may be inducers or antagonists.     

Water column monitoring near oil installations in the North Sea 2001-2004

Fisheries have been vital to coastal communities around the North Sea for centuries, but this semi-enclosed sea also receives large amounts of waste. It is therefore important to monitor and control inputs of contaminants into the North Sea. Inputs of effluents from offshore oil and gas production platforms (produced water) in the Norwegian sector have been monitored through an integrated chemical and biological effects programme since 2001. The programme has used caged Atlantic cod and blue mussels. PAH tissue residues in blue mussels and PAH bile metabolites in cod have confirmed exposure to effluents, but there was variation between years. Results for a range of biological effects methods reflected exposure gradients and indicated that exposure levels were low and caused minor environmental impact at the deployment locations. There is a need to develop methods that are sufficiently sensitive to components in produced water at levels found in marine ecosystems.     

On the evaluation of temperature trends in the tropical troposphere

A series of model experiments with the coupled Max-Planck-Institute ECHAM5/OM climate model have been investigated and compared with microwave measurements from the Microwave Sounding Unit (MSU) and re-analysis data for the period 1979?C2008. The evaluation is carried out by computing the Temperature in the Lower Troposphere (TLT) and Temperature in the Middle Troposphere (TMT) using the MSU weights from both University of Alabama (UAH) and Remote Sensing Systems (RSS) and restricting the study to primarily the tropical oceans. When forced by analysed sea surface temperature the model reproduces accurately the time-evolution of the mean outgoing tropospheric microwave radiation especially over tropical oceans but with a minor bias towards higher temperatures in the upper troposphere. The latest reanalyses data from the 25?year Japanese re-analysis (JRA25) and European Center for Medium Range Weather Forecasts Interim Reanalysis are in very close agreement with the time-evolution of the MSU data with a correlation of 0.98 and 0.96, respectively. The re-analysis trends are similar to the trends obtained from UAH but smaller than the trends from RSS. Comparison of TLT, computed from observations from UAH and RSS, with Sea Surface Temperature indicates that RSS has a warm bias after 1993. In order to identify the significance of the tropospheric linear temperature trends we determined the natural variability of 30-year trends from a 500?year control integration of the coupled ECHAM5 model. The model exhibits natural unforced variations of the 30?year tropospheric trend that vary within ±0.2?K/decade for the tropical oceans. This general result is supported by similar results from the Geophysical Fluid Dynamics Laboratory (GFDL) coupled climate model. Present MSU observations from UAH for the period 1979?C2008 are well within this range but RSS is close to the upper positive limit of this variability. We have also compared the trend of the vertical lapse rate over the tropical oceans assuming that the difference between TLT and TMT is an approximate measure of the lapse rate. The TLT?CTMT trend is larger in both the measurements and in the JRA25 than in the model runs by 0.04?C0.06?K/decade. Furthermore, a calculation of all 30?year TLT?CTMT trends of the unforced 500-year integration vary between ±0.03?K/decade suggesting that the models have a minor systematic warm bias in the upper troposphere.     

An inter-hemispheric comparison of the tropical storm response to global warming

Model studies do not agree on future changes in tropical cyclone (TC) activity on regional scales. We aim to shed further light on the distribution, frequency, intensity, and seasonality of TCs that society can expect at the end of the twenty-first century in the Southern hemisphere (SH). Therefore, we investigate TC changes simulated by the atmospheric model ECHAM5 with T213 (~60 km) horizontal resolution. We identify TCs in present-day (20C; 1969–1990) and future (21C; 2069–2100) time slice simulations, using a tracking algorithm based on vorticity at 850 hPa. In contrast to the Northern hemisphere (NH), where tropical storm numbers reduce by 6 %, there is a more dramatic 22 % reduction in the SH, mainly in the South Indian Ocean. While an increase of static stability in 21C may partly explain the reduction in tropical storm numbers, stabilization cannot alone explain the larger SH drop. Large-scale circulation changes associated with a weakening of the Tropical Walker Circulation are hypothesized to cause the strong decrease of cyclones in the South Indian Ocean. In contrast the decrease found over the South Pacific appears to be partly related to increased vertical wind shear, which is possibly associated with an enhanced meridional sea surface temperature gradient. We find the main difference between the hemispheres in changes of the tropical cyclones of intermediate strength with an increase in the NH and a decrease in the SH. In both hemispheres the frequency of the strongest storms increases and the frequency of the weakest storms decreases, although the increase in SH intense storms is marginal.     

High-resolution correlations between Gotland and Estonia near the base of the Wenlock

The strata of the Ireviken Event can be correlated between Gotland, Sweden and the Viki core on Saaremaa, Estonia, with a high degree of precision. Most of the ten datum planes are found with a precision of better than 0.1 m in the Lower and upper Visby Beds on Gotland and high in the Mustjala Member of the Jaani Formation on Saaremaa. Five of the latest Llandovery–early Wenlock units defined by these datum planes are between c. 0.12 and 1.77 m thick on Gotland and 0.12 and 0.67 m in Estonia. The duration of each was between a few thousand and c. 31 000 years. The stratigraphic resolution achieved in the interval of the Ireviken Event is 10,000 years. Ultimate range ends are lacking within a preceding, slightly longer interval, but the pattern of intermittent presence of some taxa agrees well with an unchanged relative rate of sedimentation. Their coeval presence in different places indicates ecological, regional or more widespread changes.     

Biomarker responses as indication of contaminant effects in blue mussel (Mytilus edulis) and female eelpout (Zoarces viviparus) from the southwestern Baltic Sea

During a field study performed in spring and autumn 2001 and 2002, blue mussels (Mytilus edulis) and female eelpout (Zoarces viviparus) were collected at three locations in the Wismar Bay (Baltic Sea), and several biomarkers of contaminant effects were analysed. Besides seasonal and inter-annual variations, biomarker signals were most pronounced at the location closest to Wismar Harbour (Wendorf) in both species. Lysosomal membrane stability (LMS) was lowest and acetylcholinesterase activity (AChE) was significantly reduced. Frequency of micronuclei (MN) was significantly higher (in blue mussels), indicating mutagenic effects. In eelpout elevated levels of DNA adducts, EROD induction and PAH-metabolites were measured. Metallothionein (MT), biomarker for trace metal exposure, showed a gradient only in spring. Organochlorine contaminant analyses (PCBs, DDTs) corresponded to the observed biomarker levels. The results obtained clearly demonstrate pollution effects in the southwestern Baltic Sea. Moreover, they show that a multibiomarker approach is also applicable in a brackish water environment.