Mitigation of greenhouse gas emissions from an abandoned Baltic peat extraction area by growing reed canary grass: life-cycle assessment

Abandoned peat extraction areas are continuous emitters of GHGs; hence, abandonment of peat extraction areas should immediately be followed by conversion to an appropriate after-use. Our primary aim was to clarify the atmospheric impact of reed canary grass (RCG, Phalaris arundinacea L.) cultivation on an abandoned peat extraction area and to compare it to other after-treatment alternatives. We performed a life-cycle assessment for five different after-use options for a drained organic soil withdrawn from peat extraction: (I) bare peat soil (no management), (II) non-fertilised Phalaris cultivation, (III) fertilised Phalaris cultivation, (IV) afforestation, and (V) rewetting. Our results showed that on average the non-fertilised and fertilised Phalaris alternatives had a cooling effect on the atmosphere (?10,837 and ?477 kg CO₂-eq ha^?1 year^?1, respectively), whereas afforestation, rewetting, and no-management alternatives contributed to global warming (9,511, 8,195, and 2,529 kg CO₂-eq ha^?1 year^?1, respectively). The main components influencing the global warming potential of different after-use alternatives were site GHG emissions, carbon assimilation by plants, and emissions from combustion, while management-related emissions played a relatively minor role. The results of this study indicate that, from the perspective of atmospheric impact, the most suitable after-use option for an abandoned peat extraction area is cultivation of RCG.     

Natural radiation exposure in the Campo Arañuelo region in the surroundings of Almaraz nuclear power station (Spain)

During 1998 regional surveys were conducted to evaluate natural radiation exposure of people in the vicinity of the six Spanish nuclear power stations. Indoor radon, external gamma dose rates outdoors and indoors and radioactivity in soil were measured in these surveys. The highest mean annual effective dose to the population was found in the surroundings of the Almaraz nuclear power plant in the province of Cáceres and was mainly due to the presence of high radon concentrations in homes. In order to make a more accurate assessment of the dose coming from the radon in this area, a new and more extensive surgery on indoor radon with a total of 380 measurements was carried out in 2000 in the Campo Ara?uelo region around the Almaraz nuclear power station. From the results obtained in this survey, a population-weighted mean annual effective dose from radon exposure of 1.7 mSv y(-1), 44% lower than that previously reported in 1998, was estimated for the whole Campo Ara?uelo region. The maximum dose value due to radon exposure, about 4 mSv y(-1), was reached in the so-called La Vera area located in the north of this region. The relationship between the indoor radon concentrates experimentally measured, the geological characteristics of this geographic area and the information provided by the radiation map of the Spanish MARNA Project is also analyzed, confirming that La Vera area should be considered as a high radon level area.     

Arsenic geochemistry and health

Arsenic occurs naturally in the earth's crust and is widely distributed in the environment. Natural mineralization and activities of microorganisms enhance arsenic mobilization in the environment but human intervention has exacerbated arsenic contamination. Although arsenic is useful for industrial, agricultural, medicinal and other purposes, it exerts a toxic effect in a variety of organisms, including humans. Arsenic exposure may not only affect and disable organs of the body, especially the skin, but may also interfere with the proper functioning of the immune system. This paper, therefore, generally highlights the toxic effects of arsenic as well as its mobilization in the natural environment and possible controls. It also briefly attempts to outline the impact of arsenic on the immune system, whose alteration could lead to viral/bacterial infections.     

Toxikologische Bewertung von Rüstungsaltlasten

A method was developed for the risk assessment of a military waste site. The method consists of two steps: 1. evaluation of the exposure through different pathways and 2. derivation of substance-specific tolerable intake levels. In this first part of the paper the quantitative exposure analysis will be discussed. Exposure depends on the conditions at the contaminated site (e.g. soil characteristics), the type of utilisation (residential area, industrial area etc.) and the substance properties. In a specific utilisation scenario, e.g. as residential area, different exposure pathways are contributing to the total contaminant uptake. Because of the properties of nitroaromatic compounds like 2,4,6-trinitrotoluene (good resorption through skin and accumulation in plants) exposure via dermal soil contact and via consumption of plants gains special importance. With these two exposure pathways as examples we explain the quantification of the exposure through different pathways by so-called exposure factors. By comparing the total exposure with tolerable intake levels for the compounds, waste site specific soil pollutant levels can be established (see second part of the paper in UWSF 6/94).     

Future energy: in search of a scenario reflecting current and future pressures and trends

Environmental Economics and Policy Studies - Growing societal pressures, technological trends and government and industry actions are moving the world toward decarbonization and away from the...     

Bewertung heterogener Altlasten durch Probenahme, statistische und geostatistische Modellierung

A slack heap in Saxony serves as an example for the model procedure of evaluation heterogeneous waste sites via sampling as well as statistical and geostatistical data analysis. This paper demonstrates the usefulness of the known regulations for sampling and of the tried and proven geostatistical methods developed for assessing homogeneous wastes and the concornitantly contaminated soil. Emphasized here are the contents of iron and sulfur. Considered in addition are the concentrations of arsenic and the heat loss. To establish a conclusion, the variograms of the original data are used to evaluate the waste site in different directions and at determined depths. With the aid of a spot interpolation, further data can be calculated for additional sites which have not been sampled and can be used consequently for displaying the spatial variability. Finally, the statistical data analysis is applied using the standard methods of random sampling as an alternative to the geostatistical modeling. In this manner, the consequences for the sampling strategy can be demonstrated.     

Some pharmacokinetic aspects of PCDDs and PCDFs in mammals after administration of a fly ash extract from a municipal incinerator

Fly ash extracts were fed to male hamster (single dose), male rat (single dose and multiple dose), pregnant and lactating female rat (multiple dose). The retention of four isomers, 2,3,7,8-TCDD, 2,3,7,8-TCDF, 1,2,3,7,8-PnCDD and 2,3,4,7,8-PnCDF, was studied in the liver of the adults, foetuses and liver of the sucklings.

Liver retention was structure dependent and different for both species. Transportation of the isomers via the mother milk was 50–100 times more effective than via the placenta.

After a single intravenous dose of fly ash extract to male rats the elimination of these four isomers was studied in the liver, during a period of 10 days. Elimination rates for 2,3,7,8-TCDD, 1,2,3,7,8-PnCDD and 2,3,4,7,8-PnCDF were in the same range. Pharmacokinetic calculations were done on both tetra congeners, to obtain information about the validity of the published K_e values in the multiple dose experiments with male rats.

For 2,3,7,8-TCDF the K_e value was applicable, but for 2,3,7,8-TCDD the validity of the K_e could not be determined.     

Passive water sampling via semipermfable membrane devices (SPMDS) in concert with bivalves in the Sacramento/San Joaquin River Delta

Freshwater clams (Corbicula fluminea) and the Huckins et al. (1) semi-permeable membrane sampling device (SPMD) were simultaneously deployed at three sites on the Sacramento and San Joaquin rivers in 1990. Both clams and the SPMDs were analyzed for sequestered pesticides and polychlorinated biphenyls (PCBs) by gas chromatography with electron capture detection (GC/ECD). Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and non-ortho PCBs were quantified by high resolution mass spectrometry (MS). In general, levels of organochlorine compounds were approximately 1.6 times higher in clams on a wet weight basis than in the SPMDs, and trends in accumulation were similar except where biofouling of the SPMD membranes decreased uptake rates. Comparisons between the normalized, average levels of PCDDs accumulated showed that while octachlorodibenzo-p-dioxin (OCDD) was most prevalent in both clams and SPMDs, much higher levels of 2,3,7,8 TCDD were found in the SPMDs than in the clams; 2,3,7,8 TCDD was 32% of the profile relative to the OCDD level for the SPMDs and <1% of the clam OCDD level. PCB levels showed the clams primarily accumulated hexachlorinated PCBs while the pentachlorinated and tetrachlorinated congeners were higher in the SPMDs. Differences in profiles for homologous series among the PCBs reveal that some congeners, especially those with 2,4,5 substitution, are more likely to bioaccumulate than those with lower chlorination or adjacent unsubstituted sites. GC/MS chromatograms indicate the SPMDs also sequestered several polyaromatic hydrocarbons. GC/ECD chromatograms indicate the presence of several unidentified, early eluting compounds in the SPMDs.