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91.
Per Christensen Lone Kørnøv Eskild Holm Nielsen 《Journal of Environmental Planning and Management》2005,48(3):393-412
Since its introduction into Danish planning in 1989, Environmental Impact Assessment (EIA) has been widely discussed. At the centre of the debate the question has been whether EIA has actually offered anything new and there has been a great deal of scepticism about the efficacy of the instrument. Although, in principle EIA offers a holistic and proactive methodology, it does not seem to lead to a more holistic and proactive regulation which covers more ground than traditional planning and environmental regulation. In an evaluation of Danish experiences, this study has looked more closely at the effects of EIA. Three types of effects on projects have been examined: changes occurring prior to the formal application; changes during the EIA process; and the mitigation measures that are demanded of projects. The general conclusion is that EIA does generate a significant number of changes to projects. In approximately half of the cases studied, modifications are made prior to the formal application. During the formal EIA process, modifications were made in more than 90% of the cases. However, most of these could be considered as minor. EIA is characterized by being based upon a broad concept of the environment. It was found that a progressive narrowing of the concept of environment takes place during the course of the EIA process. 相似文献
92.
Sileika AS Stålnacke P Kutra S Gaigalis K Berankiene L 《Environmental monitoring and assessment》2006,122(1-3):335-354
There are discordant results on trends in nutrient river water quality from the economical transition countries in Europe. The present study assessed the impact of these economical changes on the load and concentration at 17 monitoring stations along the Nemunas River and its major tributaries (Lithuania and Belarus). Three time periods were evaluated: the Soviet rule command system period 1986–1991, the transfer to market economy period 1992–1996 and the post reform period 1997–2002. The most surprising result in this study, was the increased area-specific load of NO3-N from the first to the third period at almost all the sampling sites. The increase was particularly large (43–78%) at the sites in the Lithuanian part of the river. The corresponding load increase in the Belarussian part of the river was only 1–15%. The statistical analyses of concentration data confirm the strong upward NO3-N trend at the Nemunas mouth and at 5 of the 6 tributaries in the lower part of Nemunas. Temporal and spatial analysis of nitrates transport in the Nemunas River and its main tributaries revealed that nitrates mainly originate from agricultural areas. The upward trends were most likely an effect of ploughing of pastures and unbalanced crop fertilisation in combination with large storage and accumulation of soil-nitrogen during the Soviet period.On contrary to nitrate-N, the area-specific load of PO4-P decreased significantly from the first to the third period at all sites along the Nemunas River (31–86%). Seasonal (SMK) and Partial (PMK) Mann-Kendall tests on PO4-P concentrations also showed significant downward trend at 14 of 16 investigated sites. The decrease of PO4-P levels was attributed to the reduction of municipal and industrial point source emissions and to the decreased livestock numbers.The NH4-N load showed the same pattern as PO4-P. At the river mouth the load was 90 kg km−2 yr−1 during the first period compared to only 20–30 kg km−2 yr−1 in the third period. The trend test on NH4-N concentrations detected significant downward trends at 5 out of 16 sites. The declines were explained by decreased emissions from cities and large animal breeding farms.This study showed that trend analysis at multiple sites in a river basin is crucial for the understanding of the variability in time and space. Such analysis is also important for our interpretation of underlying sources and fluxes in a drainage basin over time. This is particularly important for compounds that have different source origin. 相似文献
93.
Øystein Flagstad Per Ole Syvertsen Nils ChR. Stenseth § John E. Stacy † Ingrid Olsaker ‡ Knut H. Røed ‡ and Kjetill S. Jakobsen† 《Conservation biology》2000,14(1):254-264
Abstract: Swayne's hartebeest ( Alcelaphus buselaphus swaynei ) is an endangered antelope that survives in four or five relict populations in Ethiopia. We examined the two main populations (Senkele and Nechisar) for mitochondrial (D-loop) and nuclear (microsatellite) variability in order to measure levels of genetic variation within the subspecies and degree of differentiation between populations. For comparison, we examined samples from a large population of red hartebeest ( Alcelaphus buselaphus caama ). Both swaynei and caama exhibited high levels of variation. There was significant differentiation between the populations of swaynei at Senkele and Nechisar, and gene diversity in Nechisar, the smaller of the two populations, was significantly lower than that in Senkele. Many mitochondrial haplotypes and microsatellite alleles present at high frequencies among the Senkele individuals were missing in Nechisar, suggesting that the translocation of animals from Senkele undertaken in 1974 did not contribute notably to the gene pool in Nechisar. Subsamples taken from Senkele in 1988 and 1995 showed a significant change in allele frequencies, a change that probably can be attributed to a massive population decline during this period. We recommend that both populations be protected in situ to maintain as much as possible of the diversity that exists within the taxon and that a breeding program be established. In spite of the earlier unsuccessful attempt, we argue that translocation of animals for enhancement of population size as well as genetic variation in Nechisar should be considered. 相似文献
94.
A review on human exposure to brominated flame retardants--particularly polybrominated diphenyl ethers 总被引:17,自引:0,他引:17
Brominated flame retardants (BFRs) have been and are still heavily used as additive or reactive chemicals in polymers and textiles. Only a few of the BFRs have been assessed in human subjects with a major data set on internal exposures to polybrominated diphenyl ethers (PBDEs). Increasing PBDE levels have been observed in mothers' milk from Sweden as well as in blood from Germany and Norway. The levels are in general lower than PCB levels. However, the PBDE concentrations found in the North Americans are considerably higher compared to European subjects. The PBDEs are dominated by 2,2',4,4'-tetrabromodiphenyl ether (BDE-47). Decabromodiphenyl ether (BDE-209) is reported both in the general population and in occupationally exposed persons showing the bioavailability of this high molecular weight compound. While the lower and medium brominated diphenyl ethers are persistent, BDE-209 has a fairly short half-life of approximately 2 weeks. Tetrabromobisphenol A (TBBPA) is readily eliminated in humans showing a half-life of about 2 days. Still, TBBPA is accumulated in humans but a continuous exposure to this BFR is required to maintain a certain level in the human subject. TBBPA has not been detected in the general population but in people exposed at work. The current review addresses human exposure routes and levels of BFRs. 相似文献
95.
This study employs insights largely derived from critical reflections on the common pool resources (CPR) theory to examine
the current governance arrangements in place to manage the mangrove forest at Kisakasaka, in Zanzibar, Tanzania. Kisakasaka
was used as a site for a community-based management pilot project of forest resources in Zanzibar. After some initial success
in setting up a local management structure and regulating access to the mangrove for mainly charcoal production, there are
now clear indications that forest conditions have deteriorated dramatically with concomitant ongoing resource use problems
for local villagers who have relied heavily on forest resources as a source of cash income. Extra-local factors, such as urban
population increases and associated market pressures for charcoal, are also conjectured to overlay and interact with the institutional
problems at Kisakasaka. As a result, over concern about the deterioration in the condition of the mangrove forest, the responsible
government authority decided not to renew the community-based governance arrangements after an initial five-year pilot period.
While revealing the inadequacies of existing governance arrangements and of its relationship to deteriorating forest conditions
at Kisakasaka, this study concludes by suggesting an approach to more fully understand forces driving local resource management
and use. 相似文献
96.
In this paper, we investigate the Precautionary Principle (PP) in action. Precaution is a fairly new concept in environmental
policy. It emerged back in the 1960s but did not consolidate until the 1980s, as it formed part of the major changes taking
place in environmental policies at that time. The PP is examined in three contexts. Firstly, we look at the meaning of the
concept and how it is disseminated through the media and public discourses to the political arenas of Denmark. Then we examine
how the idea is adopted to the political level. Thirdly, we look briefly at the first Danish translation of the principle
into a practical context, which includes translations into concrete scientific practices. It is concluded that if the PP shall
be more than a simple “idea” or a frequently used “term,” emphasis must be put on the transformation of the concept into concrete
practices, like e.g., the alternative testing regimes that we show in the case of plant growth-retarding pesticides presented
in this paper. 相似文献
97.
Recent studies indicate that secondary ozonides of cyclic alkenes are formed in atmospheric reactions and may be relatively stable. The secondary ozonides (SOZs) of cyclohexene (1), 1-methylcyclohexene (2), 4-isopropyl-1-methylcyclohexene (3) and 4-isopropenyl-1-methylcyclohexene (limonene) (4) have been characterized by rapid gas chromatography electron ionization (EI), negative and positive chemical ionization (CI: ammonia, isobutane and methane) and collision-induced dissociation (CID) mass spectrometry. Both EI and positive CI spectra were found unsuitable for reproducible analysis. However, negative CI showed stable (M−H)− ions with minor fragmentation. CID of the (M−H)− ions resulted in simple and reproducible fragmentation patterns for all four SOZs with loss of m/z 18, 44 and 60, tentatively assigned as H2O, CO2 and C2H4O2 or CO3, respectively. Thus, negative CI-MS–MS in combination with rapid gas chromatography is the preferred method for identification of secondary ozonides of cyclohexenes. 相似文献
98.
The emissions from deep-seated fires in domestic waste have been investigated. The gas phase yields of PAH, PCDD/F, PCB, HCB, particles, and metals associated to the particulate matter were analysed during a series of simulated deep-seated fires. The method of extinguishment was varied and in cases where water was used for extinguishment, the runoff water was analysed for PAH, PCDD/F, PCB, hexachlorobenzene, and metals. In total six tests were performed. In four of the tests, samples of the fire residue were analysed for PCDD/F, PCBs, and chlorobenzenes. 相似文献
99.
Blue mussels (Mytilus edulis) were exposed to an extract made of natural cyanobacterial mixture containing toxic cyanobacterium Nodularia spumigena (70-110 microg nodularin l(-1), 24-h exposure followed by 144-h depuration period in clean water). Toxin concentration increased from initial 400 to 1100 mg kg(-1) after 24-h exposure, measured by liquid chromatography/mass spectrometry (LC/MS). Acetylcholinesterase activity (AChE), a biomarker of direct neurotoxic effects, showed inhibition after 12 and 24h exposure but returned to control level during the depuration period. Catalase (CAT) activity, an indicator of oxidative stress, showed significantly elevated levels in exposed mussels but only 72 h after the end of the exposure. No change in the activity of glutathione-S-transferase (GST) involved in conjugation reactions could be observed. A gradual yet incomplete elimination of nodularin (from 1100 to 600 mg kg(-1)) was observed during the depuration period, and the tissue levels were 30% lower in clean water after 24 h. The observed increase in oxidative stress indicated by elevated CAT activity is likely connected to detoxification reactions leading to the production of reactive oxygen species, including an apparent time lag in this specific enzymatic defence response. That no change in GST activity was observed suggests that this enzyme is not significantly involved in the detoxification process of nodularin-containing cyanobacterial extract in M. edulis. 相似文献
100.
Rapid screening methods can improve the cost effectiveness, throughput, and quality of risk assessments of contaminated sites. In the present case study, the objective was to evaluate a combination of pressurized liquid extraction and 2 in vitro bioassays for the hazard assessment of surface soil sampled from 46 points across a pyrotechnical industrial site. Pressurized liquid extraction was used to rapidly produce soil-water extracts compatible with 2 high-capacity bioassays. Hazard assessment using combined toxicological and chemical screening revealed zones with relatively high potential risks of metal pollution. Multivariate data analysis provided indications that significant inhibition in the bioassays was correlated with levels of metals in the extracts, suggesting an elevated toxic potential from certain metals. Low pH and high concentrations of dissolved organic carbon were associated with increased cytotoxicity of extracts, indicating that these factors influence metal bioavailability. The cytotoxicity observed was more strongly correlated to metal concentrations in the extracts than in the soil, suggesting that measurements of total metal concentrations in soils do not provide good indications of the soil's potential toxicity. 相似文献