Environmental Monitoring and Research in the Abisko Area—An Overview

This article gives an overview of the studies on the environment surrounding the Abisko Scientific Research Station in Swedish Lapland. The long-term monitoring of the Station on processes related to the climate, and to the physical, biotic, and chemical environmental conditions is particularly addressed. Some variables are recorded since more than 100 years. The obtained data in combination with results from short-term studies and manipulation experiments are important to understand past and future conditions of the ecosystems. This has practical applications for the planning of tourism, transports, reindeer herding, and for societal purposes.     

Temporal change estimation of mercury concentrations in northern pike (Esox lucius L.) in Swedish lakes

Adequate temporal trend analysis of mercury (Hg) in freshwater ecosystems is critical to evaluate if actions from the human society have affected Hg concentrations ([Hg]) in fresh water biota. This study examined temporal change in [Hg] in Northern pike (Esox lucius L.) in Swedish freshwater lakes between 1994 and 2006. To achieve this were lake-specific, multiple-linear-regression models used to estimate pike [Hg], including indicator variables representing time and fish weight and their interactions. This approach permitted estimation of the direction and magnitude of temporal changes in 25 lakes selected from the Swedish national database on Hg in freshwater biota. A significant increase was found in 36% of the studied lakes with an average increase in pike [Hg] of 3.7 ± 6.7% per year that was found to be positively correlated with total organic carbon. For lakes with a significant temporal change the dataset was based on a mean of 30 fish, while for lakes with no temporal change it was based on a mean of 13 fish.     

Land-Use and Land-Cover Dynamics in the Central Rift Valley of Ethiopia

Understanding the complexity of land-use and land-cover (LULC) changes and their driving forces and impacts on human and environmental security is important for the planning of natural resource management and associated decision making. This study combines and compares participatory field point sampling (pfps) and remote sensing to explore local LULC dynamics. The study was conducted in two peasant associations located in the central Ethiopian Rift Valley, which is a dry-land mixed farming area exposed to rapid deforestation. From 1973–2006, the area of cropland doubled at the expense of woodland and wooded-grassland in both of the study sites. Major deforestation and forest degradation took place from 1973–1986; woodland cover declined from 40% to 9% in one of the study sites, while the other lost all of its original 54% woodland cover. Our study concludes that assessing LULC dynamics using a combination of remote sensing and pfps is a valuable approach. The two methods revealed similar LULC trends, while the pfps provided additional details on how farmers view the changes. This study documents dramatic trends in LULC over time, associated with rapid population growth, recurrent drought, rainfall variability and declining crop productivity. The alarming nature of these trends is reflected in a decrease in the livelihood security of local communities and in environmental degradation. Given these dry-land conditions, there are few opportunities to improve livelihoods and environmental security without external support. If negative changes are to be halted, action must be taken, including building asset bases, instituting family planning services, and creating opportunities outside these marginal environments.     

Black carbon-dominated PCDD/Fs sorption to soils at a former wood impregnation site

The influence of black carbon (BC) on the sorption of 17 native polychlorinated-p-dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) was studied in five soil samples from a sawmill site where wood used to be impregnated with chlorophenol preservatives. The presence of BC caused measured total organic carbon (TOC)-water distribution ratios (K(TOC)) to be a median factor of 51 (interquartile range 18-68, n=85) higher than modeled amorphous organic carbon (AOC)-water distribution ratios (K(AOC)). K(TOC) was a factor of 73+/-27 above K(AOC) for PCDFs (n=10) and a factor of 20+/-13 (n=7) for PCDDs. The reason for this difference is probably that attaining a planar configuration after sorption to BC is less thermodynamically favorable for PCDDs than for PCDFs. BC-water distribution ratios were calculated from K(TOC), K(AOC) and BC contents, and ranged from 10(9.9) (2,3,7,8-Tetra-CDD) to 10(11.5) l kg(-1) (Octa-CDF). More than 90% of the PCDD/Fs in the soil was calculated to be BC-sorbed. Dissolved organic carbon (DOC)-water distribution ratios were measured to be in the same order of magnitude as K(AOC). This study shows that strong sorption to BC should be included when assessing ecotoxicological risk or modeling transport to groundwater of PCDD/Fs in soil.     

Total Contents and Sequential Extraction of Heavy Metals in Soils Irrigated with Wastewater,Akaki, Ethiopia

The Akaki River, laden with untreated wastes from domestic, industrial, and commercial sources, serves as a source of water for irrigating vegetable farms. The purpose of this study is to identify the impact of waste-water irrigation on the level of heavy metals and to predict their potential mobility and bioavailability. Zn and V had the highest, whereas Hg the lowest, concentrations observed in the soils. The average contents of As, Co, Cr, Cu, Ni, Zn, V, and Hg of both soils; and Pb and Se from Fluvisol surpassed the mean + 2 SD of the corresponding levels reported for their uncontaminated counterparts. Apparently, irrigation with waste water for the last few decades has contributed to the observed higher concentrations of the above elements in the study soils (Vertisol and Fluvisol) when compared to uncontaminated Vertisol and Fluvisol. On the other hand, Vertisol accommodated comparatively higher average levels of Cr, Cu, Ni, Zn, etc V, and Cd, whereas high contents of Pb and Se were observed in Fluvisol. Alternatively, comparable levels of Co and Hg were found in either soil. Except for Ni, Cr, and Cd in contaminated Vertisol, heavy metals in the soils were not significantly affected by the depth (0–20 and 30–50 cm). When the same element from the two soils was compared, the levels of Cr, Cu, Ni, Pb, Se, Zn, V, Cd at 0–20 cm; and Cr, Ni, Cu, Cd, and Zn at 30–50 cm were significantly different. Organic carbon (in both soils), CEC (Fluvisol), and clay (Vertisol) exhibited significant positive correspondences with the total heavy metal levels. Conversely, Se and Hg contents revealed perceptible associations with carbonate and pH. The exchangeable fraction was dominated by Hg and Cd, whereas the carbonate fraction was abounded with Cd, Pb, and Co. conversely, V and Pb displayed strong affinity to reducible fraction, where as Cr, Cu, Zn, and Ni dominated the oxidizable fraction. Cr, Hg, Se, and Zn (in both soils) showed preference to the residual fraction. Generally, a considerable proportion of the total levels of many of the heavy metals resided in non residual fractions. The enhanced lability is generally expected to follow the order: Cd > Co > Pb > Cu > Ni > Se > V and Pb > Cd > Co > Cu > Ni > Zn in Vertisol and Fluvisol, respectively. For the similar wastewater application, the soil variables influence the status and the distribution of the associated heavy metals among the different soil fractions in the study soils. Among heavy metals that presented relatively elevated levels and with potential mobility, Co, Cu, Ni (either soil), V (Vertisol), Pb, and Zn (Fluvisol) could pose health threat through their introduction into the food chain in the wastewater irrigated soils.     

Comparison of techniques for estimating PAH bioavailability: uptake in Eisenia fetida, passive samplers and leaching using various solvents and additives

The aim of this study was to evaluate different techniques for assessing the availability of polycyclic aromatic hydrocarbons (PAHs) in soil. This was done by comparing the amounts (total and relative) taken up by the earthworm Eisenia fetida with the amounts extracted by solid-phase microextraction (SPME), semi-permeable membrane devices (SPMDs), leaching with various solvent mixtures, leaching using additives, and sequential leaching. Bioconcentration factors of PAHs in the earthworms based on equilibrium partitioning theory resulted in poor correlations to observed values. This was most notable for PAHs with high concentrations in the studied soil. Evaluation by principal component analysis (PCA) showed distinct differences between the evaluated techniques and, generally, there were larger proportions of carcinogenic PAHs (4-6 fused rings) in the earthworms. These results suggest that it may be difficult to develop a chemical method that is capable of mimicking biological uptake, and thus estimating the bioavailability of PAHs.     

Role of sea-ice biota in nutrient and organic material cycles in the northern Baltic Sea

This paper compiles biological and chemical sea-ice data from three areas of the Baltic Sea: the Bothnian Bay (Hailuoto, Finland), the Bothnian Sea (Norrby, Sweden), and the Gulf of Finland (Tv?rminne, Finland). The data consist mainly of field measurements and experiments conducted during the BIREME project from 2003 to 2006, supplemented with relevant published data. Our main focus was to analyze whether the biological activity in Baltic Sea sea-ice shows clear regional variability. Sea-ice in the Bothnian Bay has low chlorophyll a concentrations, and the bacterial turnover rates are low. However, we have sampled mainly land-fast level first-year sea-ice and apparently missed the most active biological system, which may reside in deformed ice (such as ice ridges). Our limited data set shows high concentrations of algae in keel blocks and keel block interstitial water under the consolidated layer of the pressure ridges in the northernmost part of the Baltic Sea. In land-fast level sea-ice in the Bothnian Sea and the Gulf of Finland, the lowermost layer appears to be the center of biological activity, though elevated biomasses can also be found occasionally in the top and interior parts of the ice. Ice algae are light limited during periods of snow cover, and phosphate is generally the limiting nutrient for ice bottom algae. Bacterial growth is evidently controlled by the production of labile dissolved organic matter by algae because low growth rates were recorded in the Bothnian Bay with high concentrations of allochthonous dissolved organic matter. Bacterial communities in the Bothnian Sea and the Gulf of Finland show high turnover rates, and activities comparable with those of open water communities during plankton blooms, which implies that sea-ice bacterial communities have high capacity to process matter during the winter period.     

Levels of chlorinated compounds (CPs, PCPPs, PCDEs, PCDFs and PCDDs) in soils at contaminated sawmill sites in Sweden

Soil samples from five contaminated sawmill sites in Sweden were characterized with respect to chlorophenols (CP), chlorinated phenoxy phenols (PCPP, hydroxylated chlorinated diphenyl ethers), chlorinated diphenyl ethers (PCDE), chlorinated dibenzofurans (PCDF) and chlorinated dibenzo-p-dioxins (PCDD). The composition of chlorinated compounds in the soil samples was compared to the composition of two preservatives commonly used in the Scandinavian wood impregnation industry: the 2,3,4,6-tetrachlorophenol preservative called Ky-5 and the pentachlorophenol preservative Dowicide G. The levels of CPs in the soil samples ranged from 0.1 to 4500 mgkg-1 d.w., PCPPs from <0.15 to 940 mgkg-1 d.w., PCDEs from <38 to 6800 microgkg-1 d.w., PCDFs from 7.4 to 18000 microgkg-1 d.w. and PCDDs from 9.9 to 35000 microgkg-1 d.w. The resulting WHO-TEQ of PCDD/Fs in the soil samples ranged from 0.14 to 3000 microgkg-1 d.w. Despite a wide range of concentrations the congener compositions were similar within tetrachlorophenate and pentachlorophenate contaminated soils respectively. The contamination at each sawmill site may be linked to the use of either a tetrachlorphenol preservative, e.g. Ky-5, or a pentachlorophenol preservative, e.g. Dowicide G. Best-fit calculations were used to compare the chlorinated phenol contents of the preservatives to those of the soil samples. This revealed a positive correlation between the hydrophobicity (logKow) of contaminants and the ratio of their levels in soil to preservatives. The relative abundance of the chlorinated compounds varied greatly between the five sites studied, suggesting that their transport parameters differ substantially.     

Concentrations and Pools of Heavy Metals in Urban Soils in Stockholm,Sweden

The concentrations of heavy metals (Cd, Cr, Cu, Hg, Ni, Pb andZn) and arsenic (As) were surveyed and the metal pools estimatedin soils in Stockholm Municipality. The sampling sites were distributed all over the entire municipality with a higher sampling density in the city centre. Soils were sampled to a maximum depth of 25 to 60 cm. Soil texture, total-C content, electrical conductivity and pH were analysed. Heavy metal concentrations were determined after wet digestion with boiling7 M HNO₃.The results showed a wide range in heavy metal concentrations, as well as in other soil properties. The city centre soils constituted a rather homogeneous group whereas outside this areano geographical zones could be distinguished. These soils were grouped based on present land use, i.e. undisturbed soils, public parks, wasteland (mainly former industrial areas), and roadside soils. The city centre and wasteland soils generally hadenhanced heavy metal concentrations to at least 30 cm depth compared to park soils outside the city centre and rural (arable)soils in the region, which were used to estimate background levels. For example, the mean Hg concentration was 0.9 (max 3.3)mg kg^-1 soil at 0–5 cm and 1.0 (max 2.9) at 30 cm depth in the city centre soils, while the background level was 0,04 mg kg^-1. Corresponding values for Pb were 104 (max 444) and135 (max 339) mg kg^-1, at 0–5 and 30 cm, respectively, while the background level was 17 mg kg^-1.The average soil pools (0–30 cm depth) of Cu, Pb and Zn were 21,38 and 58 g m^-2 respectively, which for Pb was 3–4 timeshigher and for Cu and Zn 1.5–2 times higher than the backgroundlevel. The total amount of accumulated metals (down to 30 cm)in the city centre soils (4.5^*10 ⁶ m² public gardens and green areas) was estimated at 80, 1.1, 120 and 40 t for Cu, Hg, Pb and Zn, respectively. The study showed (1) thatfrom a metal contamination point of view, more homogeneous soilgroups were obtained based on present land use than on geographicdistance to the city centre, (2) the importance of establishing a background level in order to quantify the degree of contamination, and (3) soil samples has to be taken below the surface layer (and deeper than 30 cm) in order to quantify theaccumulated metal pools in urban soils.     

Temporal trend of bis(4-chlorophenyl) sulfone, methylsulfonyl-DDE and -PCBs in Baltic guillemot (Uria aalge) egg 1971-2001--a comparison to 4,4'-DDE and PCB trends

The dynamics of organohalogen contaminants and their metabolites are best studied over time by analysis of biota at high trophic levels. In this study, time trends, 1971-2001, of bis(4-chlorophenyl) sulfone (BCPS) and of methylsulfonyl-substituted metabolites of PCBs and 4,4'-DDE, were investigated in eggs of guillemot (Uria aalge) hatching in the Baltic Proper. Temporal trends of PCBs, trans-nonachlor, beta-HCH, 4,4'-DDT, and 4,4'-DDE were also assessed. Tris(4-chlorophenyl) methane (TCPMe), a 4,4'-DDT by-product, was detected in the eggs. The concentration of BCPS ranged between 2.6-0.76 microg/g on a lipid weight basis over the three decades and showed a significant 1.6% annual decrease. Three metabolites of PCBs, i.e. 3'-MeSO2-CB101, 4'-MeSO2-CB101 and 4-MeSO2-CB149, were quantified in all samples over time and showed an annual decrease of approximately 3% compared to MeSO2-DDE with a decrease of 8.9%. The methylsulfonyl-PCB and -DDE metabolites are eliminated more slowly than the persistent PCB congeners and 4,4'-DDE. Trans-nonachlor decreases by 16% compared to 19% and 9% for 4,4'-DDT and beta-HCH, respectively. The concentration of TCPMe in guillemot decreased by 8.2% per year. A linear relationship was found between TCPMe and 4,4'-DDE concentrations which supports the theory that TCPMe has an origin as a contaminant in commercial 4,4'-DDT products. The very slow decrease in BCPS concentrations is notable and remains to be explained. BCPS is still present at rather high concentrations in the guillemot eggs. The enantiomeric fraction varied between 0.27 and 0.67 which indicates less of a specific retention of the chiral MeSO2-PCBs in guillemot eggs than in grey seal tissues, for example. Independent of meta- or para-substitution of the sulfone group, the most accumulative atropisomer of each of four MeSO2-PCB pairs has been assigned an absolute R structure.