Quantifying the drivers of the increasing colored organic matter in boreal surface waters

Long-term monitoring of surface water quality has shown increasing concentrations of colored dissolved organic matter (CDOM) across large parts of the northern latitudes. This has increased purification costs for domestic water works. Appropriate abatement actions require better knowledge of the governing factors for the increase, and this has motivated a growing scientific interest in understanding the factors and mechanisms promoting the CDOM increase. A proposed water color model for an important raw water source for Oslo, Norway, is based on the precipitation's amount and mobile ion concentration. The model explained more than 93% of the temporal variation in CDOM between 1983 and 2008. The model structure was also tested on three adjacent raw water sources and was found to explain 75-82% of the CDOM development throughout the same period. The long-term trend of increasing CDOM was closely related to the decline in sulfate and chloride concentrations in precipitation. Furthermore, interannual fluctuations in CDOM were explained by variation in predominant water flow paths, depending on amounts and intensity of precipitation, both of which are predicted to increase in several parts of the northern latitudes according to climate change scenarios.

Aquatic mosses as a monitoring tool for 137Cs contamination in streams and rivers-a field study from central southern Norway

Mosses are frequently used as biomonitors for trace element pollution in the aquatic environment. The purpose of this study was to assess their usefulness as a tool in monitoring and in regional surveys of radioactive contamination. Specimens of the aquatic mosses, Fontinalis antipyretica and F. dalecarlica, were transplanted from non-contaminated areas to streams and rivers in the Norwegian Jotunheimen Mountains and neighbouring lowland areas that had received radioactive fallout after the Chernobyl accident. Equilibrium concentrations of 137Cs in the exposed mosses were reached after a few weeks. Two series from 20 streams in 1994 and 1996 show linear correlations between activities in water and moss samples and biomagnification ratios of 10(4) - 10(5). We conclude that mosses are better suited for monitoring purposes than water samples, because they provide values integrated over weeks while the radioactivity in surface waters can be subject to rapid variations according to hydrological events. The activity concentrations in aquatic mosses can be easily measured with good precision even when aqueous concentrations are below the limit of detection. Use of aquatic mosses also reduces the logistic problems of transporting large volumes of water, especially in areas inaccessible by road.

Importance of soluble metals and reactive oxygen species for cytokine release induced by mineral particles

The mechanisms for particle-induced health effects are not well understood, but inflammation seems to be of importance. Previously, we have shown that stone quarry particles with various mineral and metal content differed widely in potency to induce inflammatory cytokines (IL-6, IL-8 and TNF-alpha) in different types of lung cells. In this study we investigated if the observed cytokine responses were associated with the soluble or insoluble components of the stone particles and if there was a relationship between the differential cytokine release and generation of reactive oxygen species (ROS). Exposure of the human alveolar cell line A549 to the different particle leachates (pH 7.4 and 4.0) did not induce corresponding differential increases in the IL-8 release as observed with whole particles. Increase in ROS production, measured as dichlorofluorescein-fluorescence, was only demonstrated after exposure of A549 cells to the pH 4.0 extract from basalt. Furthermore, generation of ROS was found in neutrophils but not in A549 cells and primary macrophages after exposure to suspensions of the solid particles. However, no obvious differences in potency among the different particles were demonstrated. In summary, other mechanisms than particle-induced ROS formation seem to be responsible for the differential induction of IL-8. Furthermore, our findings indicate that the differential ability to induce IL-8 release in lung cells is attributed to the solid components of the stone particles.

Determination of aluminium in samples from bone and liver of elderly Norwegians

Recent reports associating aluminium with several skeletal and neurological disorders in humans suggest that exposure to aluminium may pose a health hazard. In connection with an epidemiological study on aluminium and Alzheimer's disease, information on the body burden of aluminium was needed. Aluminium is stored in the body mainly in bone and soft tissues such as the liver. Therefore, an analytical procedure was developed for the determination of aluminium in the head of femur and the liver using graphite furnace atomic absorption spectrometry. Problems in such analyses are associated with low levels of aluminium, risk of contamination during sample preparation, inhomogeneity of the sample tissues, and complexity of the matrices. Bone samples gave poorer repeatability compared to liver samples and up to four replicate analyses were performed. In the analyses of the digested bone samples, severe chemical interference occurred when these either contained much dissolved bone mineral or had a high A1 concentration. It is possible that this interference is brought about by formation of aluminium phosphate in the graphite tube. The analytical results for bones are given relative to ash weight because the samples sometimes contained a lot of fat. The ash weight of the bone tissue varied between 8 and 69 per cent. The material consisted of 84 samples of head of femur and 95 liver samples from deceased elderly Norwegians. Two cases had high A1 levels in bone (16.8 and 18.0 mg/kg ash weight) and liver (10 and 22.7 mg/kg dry weight) tissues. The remaining cases showed about ten to fifteen-fold variation of the A1 level in both liver (0.4 - 5.7 mg/kg) and bone (0.5 - 5.8 mg/kg). There was no correlation between the level in liver and bone when the two cases with the highest levels were excluded.