Influence of pre-treatment step on PAHs analyses in contaminated soils

There is no specific standardization for the pre-treatment of a soil sample for PAHs analyses. The ISO/FDIS 14507 method for soil quality gives a guidance for sample pre-treatment before measurement of organic contaminants in soil. It refers to cryogenic crushing which is not so easy to carry out. So, analysts lead to develop in house methods which can be very different from a laboratory to another and can involve deviations in the pollution quantification. This study has explored different ways of drying, grinding and sieving in order to determine the influence of the soil sample handling on the measured pollutant concentration. It appears that the influence of pre-treatment depends on the soil nature and on the PAHs distribution. As a conclusion, it is advised "light" drying ways like air drying or drying at 40 degrees C in a drying oven instead of more "drastic" ways (freeze-drying, cryogenic crushing) which can induce some losses. Crushing and sieving are also recommended for more reproducible measures.     

Chloride imbalances in soil lysimeters

The assumption that soil neither acts as a source or a sink of chloride is evaluated by incubating soil cores in lysimeters in a climate chamber under controlled conditions. Some of the lysimeters acted as a sink while others acted as a source of chloride. Considerable amounts of organic chlorine were lost by leaching. The loss by leaching of organic chlorine could only explain part of the discrepancy in the lysimeters where the soil acted as a sink and it could certainly not explain the cases where the soil acted as a source.The storage of organic chlorine was four times larger than the storage of chloride and comparably small changes in the organic chlorine storage will thus have a considerable influence on the chloride budget. However, the soil was too heterogeneous to determine whether a change in the storage had taken place or not. It is concluded that the observed chloride surplus and also, at least to some extent, the observed chloride deficit, most likely was caused by net-changes in the storage of organic chlorine in soil. An inverse correlation was found between the initial chloride content of the soil and the imbalance in the chloride budget.Dry deposition of chloride is generally assumed to equal the run-off minus the wet deposition. Extrapolation to the field situation suggests that the output of organic chlorine by soil leachate is at risk to cause an underestimation of the dry deposition by about 25%.     

Morphometry and hydrology of the four large lakes of Sweden

The four largest Swedish lakes V?nern, V?ttern, M?laren and Hj?lmaren all have a tectonic origin with multidirectional fault fissures, which influence the topography of the bottoms and the creation of subbasins. All the four lakes have been subject to several glacials, the latest of which started to recede from central Sweden c. 10,000 years ago. The many differences between the four lakes can be explained by their shapes, sizes and the relation between the sizes of the drainage basins and the size of the lakes. This paper focuses on processes considered relevant to aquatic organisms of the lakes: water balance, water residence time, water temperature, water exchange between subbasins within the lakes, and other internal water movements. Links between pollution, water exchange and retention of nutrients are discussed with an example from Lake V?nern.     

Hydroxylated PCB metabolites in nonhatched fulmar eggs from the Faroe Islands

Thirty-six polychlorinated biphenylols (OH-PCBs) congeners were characterized in Fulmar (Fulmarus glacialis) eggs collected from the Faroe Islands. The seven most abundant congeners were quantified in 19 samples, and the sigmaOH-PCB concentrations ranged between 0.92 and 4.0 ng g(-1) fresh weight (f.w.). These eggs constitute a part of the traditional diet for at least a part of the population on the Faroe Islands and may contribute to the high levels of these contaminants found in the blood of pregnant Faroese women. Because the metabolites are present in the nonhatched fulmar egg, it is concluded that the OH-PCBs are transferred to the egg before laying. High levels, 3300-18,000 ng g(-1) l.w., of sigmapolychlorinated biphenyls (PCB) were determined in the fulmar eggs, which are a considerable source for human exposure. The high PCB levels are a source for metabolic formation of hydroxylated PCBs.     

Screening of organic halogens and identification of chlorinated benzoic acids in carbonaceous meteorites

The occurrence of halogenated organic compounds measured as a sum parameter and the evidence of chlorinated benzoic acids in four carbonaceous meteorites (Cold Bokkeveld, Murray, Murchison and Orgueil) from four independent fall events is reported. After AOX (Adsorbable organic halogen) and EOX (Extractable organic halogen) screening to quantify organically bound halogens, chlorinated organic compounds were analyzed by gas chromatography. AOX concentrations varying from 124 to 209 microg Cl/g d.w. were observed in carbonaceous meteorites. Ion chromatographic analysis of the distribution of organically bound halogens performed on the Cold Bokkeveld meteorite revealed that chlorinated and brominated organic compounds were extractable, up to 70%, whereas only trace amounts of organofluorines could be extracted. Chlorinated benzoic acids have been identified in carbonaceous meteorite extracts. Their presence and concentrations raise the question concerning the origin of halogenated, especially chlorinated, organic compounds in primitive planetary matter.     

Possibilities for improving nitrogen use from organic materials in agricultural cropping systems

Nitrogen release from organic nutrient sources in soil is influenced by a range of factors such as soil temperature and moisture, and chemical composition of the organic material. Chemical composition can, to a certain degree, be controlled to increase the synchronization of nitrogen (N) release with plant N demand, whereas climatic factors cannot be controlled and so must be taken into account when planning management measures. In this paper, we discuss different ways to affect N release through manipulation of the chemical composition of fresh or pretreated plant materials and animal manures, timing of incorporation, and intentional distribution during application. We conclude by giving an overview of off-farm options that may need to be implemented to achieve improved use of N, especially in agricultural systems with surplus N.     

Effect of different soil types on the enchytraeids Enchytraeus albidus and Enchytraeus luxuriosus using the herbicide Phenmedipham

Soil ecotoxicology studies are usually performed in standard soils, such as the OECD (Organization for Economic Cooperation and Development) artificial soil or the LUFA St. 2.2, a natural soil. When assessing the toxic effects in the environment, soil properties are often different from those in standard soils, which might lead to a different exposure situation for the test species and, therefore, to a different evaluation of the risk of the test substance. Selected to cover a broad range of properties and based on the Euro-Soils concept, 18 different soils were studied regarding their suitability to two test species: Enchytraeus albidus and Enchytraeus luxuriosus (Enchytraeidae). In reproduction tests, the test species reacted differently to the tested soils, but both enchytraeids did not survive in acid soils (i.e. pH相似文献   

The Water Framework Directive: stakeholder preferences and catchment management strategies--are they reconcilable?

The key objective of the European Water Framework Directive (WFD) is to promote sustainable water use by protecting water resources. Here, we investigate how the economic consequences of a set of water management regulations is received by a group of stakeholders in the R?nne? catchment. We explore three themes from an economic point of view: i) perceived causes of eutrophication, ii) preferences regarding water use, and iii) the extent to which the polluter-pays principle should be applied. There is a common understanding about the intentions in the WFD to enhance cost-effective water use. All stakeholder groups largely share a similar picture of the causes of water quality deterioration. However, there is not one cost-effective and fair solution. Several mixes of remedial measures within the same catchment are possible, depending on the scale of action. Despite potential economic gains from cooperation between sectors, the participants regard the individual polluter-pays principle as the most feasible mode of funding for remedial programs, supported by subsidies. There is little demand for more market institutions (emission fees, tradable emission permits). The stakeholders have a conservative view of water management, i.e. they accept the present combination of regulations and economic incentives, and they are fully aware of the complexity of the issue. In general, the WFD recommendations for the calculation of cost-effective abatement strategies seem to imply an underestimation of the value of external effects in the decision-making process.     

Applicability of Fenton and H2O2/UV reactions in the treatment of tannery wastewaters

In this paper we evaluated the H2O2/UV and the Fenton's oxidation processes for the treatment of tannery wastewater under different experimental conditions. Efficiencies were judged by the amounts of organic substances degraded or eliminated under these treatment techniques. Daphnia magna and Vibrio fischeri were used to monitor toxicity. Organic compounds contained in the untreated and treated tannery wastewater were determined and identified using substance specific techniques. Gas chromatography-mass spectrometry (GC-MS) in positive electron impact (EI(+)) mode was applied to determine volatile organics. Atmospheric pressure ionization (API) mass (MS) and tandem mass spectrometry (MS-MS) coupled with flow injection analysis (FIA) or liquid chromatography (LC) were used to detect or identify polar organic pollutants. The experimental results indicated that both oxidation processes--H2O2/UV at pH 3 and Fenton at pH 3.5--are able to reduce TOC content by mineralisation of the organic compounds.