The Expansion of Farm-Based Plantation Forestry in Vietnam

This study targets plantation forestry by farm households (small holders), which is increasing globally and most rapidly in China and Vietnam. By use of an interdisciplinary approach on three study sites in Vietnam, we examined the trends in farmers’ tree planting over time, the various pre-requisites for farm-based plantation forestry and its impact on rural people’s livelihood strategies, socio-economic status, income and security. The findings indicated a change from subsistence to cash-based household economy, diversification of farmers’ incomes and a transformation of the landscape from mainly natural forests, via deforestation and shifting cultivation, to a landscape dominated by farm-based plantations. The trend of transformation, over a period of some 30 years, towards cash crops and forestry was induced by a combination of policy, market, institutional, infrastructural and other conditions and the existence of professional farming communities, and was most rapid close to the industrial market.     

Water Exchange on a Geological Timescale - Examples from Two Coastal Sites in the Baltic Sea

The water turnover of two coastal areas, Forsmark and Laxemar-Simpevarp, has been modeled for 13 selected years between 6500 bc and 9000 ad by utilizing information about past, present, and future bathymetry. The Forsmark area can be described as an open-ended funnel, and is analyzed with a 3D-model (MIKE 3-FM); the Laxemar area is partitioned into clusters of sub-basins treated with a discrete coupled basin model (CouBa). In all simulations, the main variation factor is the land uplift. The 3D-model domain is successively modified. For the CouBa approach the successive basin configurations are objectively deduced based on the 3D domain modifications. The average age (AvA) of the resident water relative to the open coast is generally lower for the Forsmark area. A typical progression is that the AvA values increase until a sub-basin ceases to be connected to the coastal zone. This disconnection is often preceded by a lowered AvA.     

Comparison of organohalogen compounds in a white-tailed sea eagle egg laid in 1941 with five eggs from 1996 to 2001

Eggs laid by white-tailed sea eagles (Haliaeetus albicilla), one in 1941 and five eggs between 1996 and 2001, all from the same geographical region of the Baltic Sea, were screened for organohalogen substances. The 1941 egg contained hexachlorobenzene (HCB), but did not contain either of the pesticides hexachlorocyclohexane (HCH) or p,p′-DDT, nor any metabolites of the latter. In contrast, the more recent eggs (REs) contained all of these compounds. Of the seven polychlorinated biphenyls (PCBs) analyzed (CB28, −52, −101, −118, −138/−163, −153 and 180), only the more highly chlorinated congeners were detected in the 1941 sample, with CB153 followed by CB180 showing the highest concentrations. All eggs demonstrated the same congener pattern with respect to the more highly chlorinated PCBs, but concentrations were approximately 70-230 times higher in the REs. All of the polychlorinated-p-dioxin and dibenzofuran (PCDD/Fs) congeners analyzed were detected in the eggs, with the dominant congener being 2,3,4,7,8-PeCDF (1250 pg/g l.w. in 1941 and 1540 pg/g l.w. (GM) for the REs, respectively). None of the other congeners exceeded 400 pg/g l.w., and the concentrations of 2,3,7,8-TCDD, 2,3,7,8-TCDF and 1,2,3,7,8-PeCDF were all lower in the REs. None of five congeners of polybrominated diphenyl ethers (PBDEs) found in the REs was detected in the egg from 1941. The three methoxylated brominated diphenyl ethers (MeO-BDEs) analyzed were found at similar levels and with a similar congener pattern in REs as in the egg from 1941.In conclusion, this study has shown the absence of DDE and PBDE and the presence of HCB and PCBs in a white-tailed sea eagle egg laid in 1941, and a strong increase of PCBs, DDE and PBDE in white-tailed sea eagle eggs from the same area in 1996-2001. The MeO-BDEs were found in similar concentrations in the analyzed eggs. The 1941 sample shows substantial concentrations of PCDD/Fs, noteworthy in the same magnitude as in the recent samples, illustrating the historical and recent exposure of these compounds.     

Characterization of dioxin-like contamination in soil and sediments from the ��hot spot�� area of petrochemical plant in Pancevo (Serbia)

Purpose

Combinatorial bio/chemical approach was applied to investigate dioxin-like contamination of soil and sediment at the petrochemical and organochlorine plant in Pancevo, Serbia, after the destruction of manufacturing facilities that occurred in the spring of 1999 and subsequent remediation actions.

Materials and methods

Soil samples were analyzed for indicator polychlorinated biphenyls (PCBs) by gas chromatography/electron capture detection (GC/ECD). Prioritized soil sample and sediment samples from the waste water channel were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). Microethoxyresorufin o-deethylase (Micro-EROD) and H4IIE?Cluciferase bioassays were used for monitoring of dioxin-like compounds (DLC) and for better characterization of dioxin-like activity of soil samples.

Results

Bioanalytical results indicated high dioxin-like activity in one localized soil sample, while the chemical analysis confirmed the presence of large quantities of DLC: 3.0?×?10⁵ ng/g d.w. of seven-key PCBs, 8.2 ng/g d.w. of PCDD/Fs, and 3.0?×?10⁵ ng/g d.w. of planar and mono-ortho PCBs. In the sediment, contaminant concentrations were in the range 2?C8 ng/g d.w. of PCDD/Fs and 9?C20 ng/g d.w. of PCBs.

Conclusions

This study demonstrates the utility of combined application of bioassays and instrumental analysis, especially for developing and transition country which do not have capacity of the expensive instrumental analysis. The results indicate the high contamination of soil in the area of petrochemical plant, and PCDD/Fs contamination of the sediment from the waste water channel originating from the ethylene dichloride production.     

Photochemical transformation of the thyroid hormone levothyroxine in aqueous solution

Purpose  

The direct aqueous photolysis of the thyroid hormone levothyroxine (T₄) has been studied.     

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.     

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.     

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.