Age dependence of the concentrations of harmful substances in Baltic herring (Clupea harengus)

The age dependence of Zn, Cu, Pb, Cd, Hg, CH₃1bHg, DDT, DDD, DDE, HCH, HCB and the PCBs have been studied in Baltic herring of 1 to 6 years of age. Lead, cadmium, mercury and the organochlorine concentrations increase significantly with age. In the case of the DDTs and the PCBs, the variations can be attribued almost totally to the combined effect of age and variations in the lipid percentage.     

Participation and empowerment-based development of socio-cultural indicators supporting regional decision-making for eco-efficiency

Abstract

This article describes a process of developing socio-cultural indicators to support local and regional decision-making for eco-efficiency. Although eco-efficiency is calculated using environmental and economic variables, decisions on local and regional levels cannot ignore the socio-cultural impacts. The indicators were developed by a participatory process that was based on involvement and empowerment of local actors. The process ensured policy relevance and meaningful indicators and advanced their future use in the decision-making.     

Organohalogen pollutants in herring from the northern Baltic Sea: concentrations, congener profiles and explanatory factors

Organohalogen contaminants were investigated in Baltic herring caught from three catchment areas in the Baltic Sea, off the coasts of Finland. Pools of both small and large herring were analysed for polychlorinated biphenyls (PCB), dibenzo-p-dioxins, dibenzofurans, naphthalenes, camphenes (toxaphene), polybrominated diphenyl ethers and the pesticide DDT and its metabolites. PCB concentrations per fresh weight in small herring were at the same level in all catchment areas, i.e. the Bothnian Bay, the Bothnian Sea and the Gulf of Finland, revealing no hot spots and reflecting most likely long term emissions and atmospheric deposition. Differences in the levels and/or congener profiles of other contaminants between catchment areas may be explained by point sources. Similar concentrations in small and large herring in the Gulf of Finland were possibly due to their common nutrition. In the other areas, differences between small and large herring most likely reflected their different food sources.     

Total and methyl mercury concentrations and fluxes from small boreal forest catchments in Finland

Total mercury (TotHg) and methyl mercury (MeHg) concentrations were studied in runoff from eight small (0.02-1.3 km2) boreal forest catchments (mineral soil and peatland) during 1990-1995. Runoff waters were extremely humic (TOC 7-70 mg l-1). TotHg concentrations varied between 0.84 and 24 ng l-1 and MeHg between 0.03 and 3.8 ng l-1. TotHg fluxes from catchments ranged from 0.92 to 1.8 g km-2 a-1, and MeHg fluxes from 0.03 to 0.33 g km-2 a-1. TotHg concentrations and output fluxes measured in runoff water from small forest catchments in Finland were comparable with those measured in other boreal regions. By contrast, MeHg concentrations were generally higher. Estimates for MeHg output fluxes in this study were comparable at sites with forests and wetlands in Sweden and North America, but clearly higher than those measured at upland or agricultural sites in other studies. Peatland catchments released more MeHg than pure mineral soil or mineral soil catchments with minor area of peatland.     

Evaluation of the European population intake fractions for European and Finnish anthropogenic primary fine particulate matter emissions

The intake fraction (iF) has been defined as the integrated incremental intake of a pollutant released from a source category or region summed over all exposed individuals. In this study we evaluated the iFs in the population of Europe for emissions of anthropogenic primary fine particulate matter (PM_2.5) from sources in Europe, with a more detailed analysis of the iF from Finnish sources. Parameters for calculating the iFs include the emission strengths, the predicted atmospheric concentrations, European population data, and the average breathing rate per person. Emissions for the whole of Europe and Finland were based on the inventories of the European Monitoring and Evaluation Programme (EMEP) and the Finnish Regional Emission Scenario (FRES) model, respectively. The atmospheric dispersion of primary PM_2.5 was computed using the regional-scale dispersion model SILAM. The iFs from Finnish sources were also computed separately for six emission source categories. The iFs corresponding to the primary PM_2.5 emissions from the European countries for the whole population of Europe were generally highest for the densely populated Western European countries, second highest for the Eastern and Southern European countries, and lowest for the Northern European and Baltic countries. For the entire European population, the iF values varied from the lowest value of 0.31 per million for emissions from Cyprus, to the highest value of 4.42 per million for emissions from Belgium. These results depend on the regional distribution of the population and the prevailing long-term meteorological conditions. Regarding Finnish primary PM_2.5 emissions, the iF was highest for traffic emissions (0.68 per million) and lowest for major power plant emissions (0.50 per million). The results provide new information that can be used to find the most cost-efficient emission abatement strategies and policies.     

Water management in Angkor: human impacts on hydrology and sediment transportation

The city of Angkor, capital of the Khmer empire from the 9th to 15th century CE, is well known for its impressive temples, but recent research has uncovered an extensive channel network stretching across over 1000 km2. The channel network with large reservoirs (termed baray) formed the structure of the city and was the basis for its water management. The annual long dry season associated with the monsoon climate has challenged water management for centuries, and the extensive water management system must have played an important role in the mitigation of such marked seasonality. However, by changing the natural water courses with off-take channels the original catchments were also reshaped. Moreover, severe problems of erosion and sedimentation in human built channels evolved and impacted on the whole water management system. This paper describes the present hydrology of the area and discusses the impacts of water management on hydrology during the Angkor era. The paper, moreover, attempts to summarise lessons that could be learnt from Angkorian water management that might apply to present challenges within the field.     

Impact of the Mekong River flow alteration on the Tonle Sap flood pulse

Rapid development in the upper reaches of the Mekong River, in the form of construction of large hydropower dams and reservoirs, large irrigation schemes, and rapid urban development, is putting water resources under stress. Recent studies have concluded that these developments will lead to flow alterations in the Mekong River. These flow alterations would threaten the sensitive ecosystems downstream, particularly Tonle Sap River, Tonle Sap Lake, its floodplain, and its gallery forest and protected areas, by changing the flood-pulse system of the lake. This article estimates the changes in parameters of the Tonle Sap flood pulse due to the aforementioned flow alterations. The impacts on the flooded area and loss of gallery forest and protected areas were analyzed using geographic information system-based methods. Relatively small rises in the dry-season lake water level would permanently inundate disproportionately large areas of floodplain, rendering it inaccessible to floodplain vegetation and eroding the productivity basis of the ecosystem. It is highly important to maintain the natural hydrological pattern of the Mekong River, particularly the dry-season water levels, to preserve Tonle Sap Lake's ecosystem productivity.