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21.
Environmental risk assessment of veterinary pharmaceuticals: development of a standard laboratory test with the dung beetle Aphodius constans 总被引:1,自引:0,他引:1
The environmental risk assessment of veterinary pharmaceuticals for dung beetles is required if the substance is an anti-parasiticide for the treatment of pasture animals. However, the demonstration of the environmental safety of those substances for dung fauna is hampered by the fact that no standardized laboratory test system is currently available. Here a test system using the temperate dung beetle species Aphodius (Agrilinus) constans (Scarabaeidae: Aphodiinae) Duftschmidt is described. The survival of first instar larvae of A. constans exposed to a model substance, dimethoate, spiked into formulated (i.e. dried, formulated and re-wetted) or fresh dung was measured over a period of three weeks. Larvae performed better in formulated dung which also proved to be more suitable for mixing-in test substances homogenously. Dimethoate caused significant larval mortality with LC50 values within a range of 1.3-2.8 mg a.s./kg dung (d.w.), depending on the dung type. Based on the data presented here, it is recommended to incorporate this new test system in the risk assessment process for veterinary pharmaceuticals. However, an international ringtest should to be performed beforehand to ensure adequate validation of the method. 相似文献
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Molecular characterisation of the dissolved organic matter of wastewater effluents by MSSV pyrolysis GC-MS and search for source markers 总被引:3,自引:0,他引:3
Microscale sealed vessel pyrolysis (MSSVpy) was used to characterise the hydrophobic (HPO) and colloid (COL) fractions of dissolved organic matter (DOM) from the effluents (EFFs) of two waste water treatment plants (WWTPs) and several primary source waters (SWs). The EFFs showed a large range of anthropogenically sourced organics - including the metabolites of industrial chemicals (e.g., dioxanes, n- and sec-alkyl substituted benzenes and long chain alkyl phenols), pharmaceuticals (e.g., N- and S-heterocycles) and human waste (e.g., S- and N-organics, steranes/sterenes) - as well as high concentrations of alkyl aromatic and N-organic products (e.g., alkyl indoles, carbazoles and β-carbolines) attributed to the treatment biota. Some anthropogenic chemicals are potentially toxic at even trace levels, whilst the N-organics may be precursors for toxic N-disinfection by-products. Much lower concentrations of just a few of the anthropogenic and N-organic products were detected by more traditional flash pyrolysis (Flash-py) of the EFF samples, reflecting the higher sensitivity of MSSVpy to many chemical functionalities. Few of these products were detected in the corresponding MSSVpy analysis of the SWs, but these samples did show relatively high abundances of lignin (e.g., alkylphenols) and carbohydrate (e.g., furans) derived products. Their lower EFF abundances are consistent with efficient removal by the water treatment procedures applied. Conversely, the detection of the anthropogenics in the treated EFFs reflects their general resistance to treatment. Their occurrence in the HPO fractions isolated by XAD resin separation suggests a potential relationship with the structurally stable macromolecular fraction of the DOM. 相似文献
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Matyssek R Wieser G Calfapietra C de Vries W Dizengremel P Ernst D Jolivet Y Mikkelsen TN Mohren GM Le Thiec D Tuovinen JP Weatherall A Paoletti E 《Environmental pollution (Barking, Essex : 1987)》2012,160(1):57-65
Forests in Europe face significant changes in climate, which in interaction with air quality changes, may significantly affect forest productivity, stand composition and carbon sequestration in both vegetation and soils. Identified knowledge gaps and research needs include: (i) interaction between changes in air quality (trace gas concentrations), climate and other site factors on forest ecosystem response, (ii) significance of biotic processes in system response, (iii) tools for mechanistic and diagnostic understanding and upscaling, and (iv) the need for unifying modelling and empirical research for synthesis. This position paper highlights the above focuses, including the global dimension of air pollution as part of climate change and the need for knowledge transfer to enable reliable risk assessment. A new type of research site in forest ecosystems ("supersites") will be conducive to addressing these gaps by enabling integration of experimentation and modelling within the soil-plant-atmosphere interface, as well as further model development. 相似文献
24.
Coupling geochemistry and transport appears unavoidable since it is rare that either of these two phenomena alone can account for the movement of solutes in groundwater. The chemical model is based on thermodynamic equilibrium. The method used is a Gibbs free energy minimization constrained by mass balances. The model calculates the aqueous speciation, the precipitation and the dissolution of pure minerals or solid solutions. The transport equation is solved by the random walk technique which avoids the problem of numerical dispersion for transport, but may be more time consuming than finite differences or elements if a large number of particles are necessary in order to get a sufficiently “smooth” solution. However, when the chemistry deals with a realistic number of elements (e.g., > 10), the cost of the chemistry computation largely dominates that of transport. Special techniques had to be developed in order to solve problems linked to the conditions present in some of the CEC CHEMVAL tests (boundary with fixed concentrations and very low Péclet numbers). The coupling consists of calculating the exchanges of chemical elements between two populations. The first population is sedentary, constituted by a mesh of fixed cells representing the composition of the solid phase. The other population is nomadic, represented by a set of particles which are advected by groundwater flow. A vector of real numbers is associated with each mobile particle. This vector accounts for the mass of each element dissolved in the moving liquid phase. For this reason, the transport equation is only solved once for the whole set of elements. The main assumptions that were necessary to perform the coupling in a simple way are discussed. Two applications are presented: (1) a verification compared to an analytical solution; and (2) the simulation of a percolation experiment through a sandstone core. 相似文献
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