Analytical techniques used to assess the environmental risk of contamination from polycyclic aromatic hydrocarbons (PAHs) typically consider only abiotic sample parameters. Supercritical fluid extraction and sorption enthalpy experiments previously suggested slow desorption rates for PAH compounds in two coal-contaminated floodplain soils. In this study, the actual PAH availability for aerobic soil microorganisms was tested in two series of soil-slurry experiments. The experimental conditions supported microbial degradation of phenanthrene if it was weakly sorbed onto silica gel. Native coals and coal-derived particles in two soils effectively acted as very strong sorbents and prevented microbial PAH degradation. The long history of PAH exposure and degree of coal contamination apparently had no influence on the capability of the microbial soil community to overcome constraints of PAH availability. Within the context of the experimental conditions and the compounds chosen, our results confirm that coal-bound PAHs are not bioavailable and hence of low environmental concern. 相似文献
Adaptation to a changing climate is unavoidable. Mainstreaming climate adaptation objectives into existing policies, as opposed to developing dedicated adaptation policy, is widely advocated for public action. However, knowledge on what makes mainstreaming effective is scarce and fragmented. Against this background, this paper takes stock of peer-reviewed empirical analyses of climate adaptation mainstreaming, in order to assess current achievements and identify the critical factors that render mainstreaming effective. The results show that although in most cases adaptation policy outputs are identified, only in a minority of cases this translates into policy outcomes. This “implementation gap” is most strongly seen in developing countries. However, when it comes to the effectiveness of outcomes, we found no difference across countries. We conclude that more explicit definitions and unified frameworks for adaptation mainstreaming research are required to allow for future research syntheses and well-informed policy recommendations.
Globally soil quality and food security continue to decrease indicating that agriculture and the food system need to adapt. Improving connection to the soil by knowledge exchange can help achieve this. We propose a framework of three types of connections that allow the targeting of appropriate messages to different groups of people. Direct connection by, for example, handling soil develops soil awareness for management that can be fostered by farmers joining groups on soil-focused farming such as organic farming or no-till. Indirect connections between soil, food and ecosystem services can inform food choices and environmental awareness in the public and can be promoted by, for example, gardening, education and art. Temporal connection revealed from past usage of soil helps to bring awareness to policy workers of the need for the long-term preservation of soil quality for environmental conservation. The understanding of indirect and temporal connections can be helped by comparing them with the operations of the networks of soil organisms and porosity that sustain soil fertility and soil functions. 相似文献
A recently designed two-chamber-lysimeter-test-system allows the detailed investigation of degradation, transport and transfer
processes of 14C-labeled substances in soil–plant–atmosphere-systems under outdoor conditions. With this test system it is feasible to distinguish
between 14C-emissions from soil surfaces and 14C-emissions from plant surfaces in soil monoliths under real environmental conditions. Special soil humidity sensors allow
the measurement of soil water content near to the soil surface, in 1 and 5 cm depth. The behavior of organic chemicals can
be followed for a whole vegetation period and a mass balance for the applied chemical can be established. Some selected results
of the herbicides isoproturon and glyphosate – using the two-chamber-lysimeter-test-system – are presented to demonstrate
its applicability for the identification and quantification of the processes that govern pesticide behavior in soil–plant-systems.
Mineralization of 14C-isoproturon was very different in four different soils; the mineralization capacity of the soils ranged from 2 to 60%. Leaching
of isoproturon in general was very low, but depending on the soil type and environmental conditions isoproturon and its metabolites
could be leached via preferential flow, especially shortly after application. For the herbicide 14C-glyphosate no accumulation of residues in the soil and no leaching of the residues to deeper soil layers could be observed
after three applications. Glyphosate was rapidly degraded to AMPA in the soil. Glyphosate and AMPA were accumulated in soy
bean nodules. 相似文献
Elevated mercury concentrations in water were reported in the prairie wetlands at Lostwood National Wildlife Refuge, ND. In order to determine whether wildlife associated with these wetlands was exposed to and then accumulated higher mercury concentrations than wildlife living near more permanent wetlands (e.g. lakes), tree swallow (Tachycineta bicolor) eggs and nestlings were collected from nests near seasonal wetlands, semi-permanent wetlands, and lakes. Mercury concentrations in eggs collected near seasonal wetlands were higher than those collected near semi-permanent wetlands or lakes. In contrast, mercury concentrations in nestling livers did not differ among wetland types. Mercury and other element concentrations in tree swallow eggs and nestlings collected from all wetlands were low. As suspected from these low concentrations, mercury concentrations in sample eggs were not a significant factor explaining the hatching success of the remaining eggs in each clutch. 相似文献
The fundamental data requirements for the authorization of plant protection products and the inclusion of active ingredients in Annex I of Council Directive 91/414/EEC are described in the Annexes II and III of this Directive. Definite instructions with regard to preconditions and for implementation and methodology (guidelines) concerning investigations with terrestrial plants are deficient. In the following, the scientific data requirements are explained for assessing the effects of plant protection products on terrestrial plants. 相似文献