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91.
The traditional northern Norwegian fish dish "m?lje", consisting of boiled cod, cod liver, cod liver oil and hard roe, is still consumed frequently during the winter months January to March. The liver of the cod is rich in lipids and the levels of persistent organic pollutants (POPs) are relatively high. To better understand the short-term consequences of this traditional meal on the plasma levels of PCBs and p,p'-DDE, individual intake of liver and cod liver oil during one meal was measured. Blood samples were collected from 33 participants before the meal, and then 4 h, 12 h and 5 days after it. Lipid-weight and wet-weight levels of 10 PCB congeners and p,p'-DDE were determined in the plasma samples and the food. The plasma levels of p,p'-DDE was found to increase significantly from 0 to 4 h, both when expressed as wet-weight (35% change) and lipid-weight (20% change). The corresponding changes (0-4 h) in wet-weight levels of the most prevalent PCB congeners were non significant. By contrast, PCB congeners with low levels in the food showed a significant drop in lipid-weight levels during the first 4 h. The observed changes were independent of amount consumed. Significant differences in fasting and non-fasting samples were found for most PCBs and p,p'-DDE. For the lipid weight levels of sum PCBs there was a significant decrease of 16% from non-fasting to fasting samples. To obtain reliable data on human levels of POPs it is, on the basis of these findings, recommended that blood samples should be collected from fasting individuals and both wet-weight and lipid-weight levels should be reported.  相似文献   
92.
Mass concentrations of sulphur dioxide were determined in parallel 24-hour samples of ambient air at a measuring site in Zagreb during a period of eight years. The methods used were the West-Gaeke's tetrachloromercurate-pararosaniline method (TCM) and the Standard British Method (SBM). Total results for the annual intervals of measuring were analyzed statistically and also discussed separately for winter and summer periods, in order to see whether they are influenced by seasonal rhythm.  相似文献   
93.
94.
Growth in the presence of sucrose was shown to confer to Arabidopsis thaliana (thale cress or mustard weed) seedlings, under conditions of in vitro culture, a high level of tolerance to the herbicide atrazine and to other photosynthesis inhibitors. This tolerance was associated with root-to-shoot transfer and accumulation of atrazine in shoots, which resulted in significant decrease of herbicide levels in the growth medium. In soil microcosms, application of exogenous sucrose was found to confer tolerance and capacity to accumulate atrazine in Arabidopsis thaliana plants grown on atrazine-contaminated soil, and resulted in enhanced decontamination of the soil. Application of sucrose to plants grown on herbicide-polluted soil, which increases plant tolerance and xenobiotic absorption, thus appears to be potentially useful for phytoremediation.  相似文献   
95.
Klán P  Holoubek I 《Chemosphere》2002,46(8):1201-1210
This review accounts for the current knowledge about the distribution, accumulation, and chemical/photochemical transformations of persistent, bioaccumulative, and toxic compounds (PBTs) in water ice, especially in the connection with polar regions and atmospheric cloud particles. (Photo)reactions on/in ice are discussed in terms of photochemistry, photobiology, paleochemistry, as well as astrophysics. Authors propose a model, in which a significant amount of some PBTs are generated by (photo)chemistry of primary pollutants in ice, which may subsequently be released to the environment. It is argued that ice photochemistry might play an important role in the chemical transformations in cold ecosystems and in the upper atmosphere, particularly now when the ozone layer is partially depleted.  相似文献   
96.
The present paper is aimed at assessing the long term behaviour of 90Sr migration from water to bottom sediments of Lake Uruskul, Southern Urals, Russia. The lake was contaminated following the nuclear accident at the Mayak nuclear complex in 1957 (the Kyshtym accident). Some transfer parameters relevant to the behaviour of 90Sr in the water-sediment system were evaluated: a) the radionuclide migration velocity from the water column to the bottom sediment, b) the radionuclide migration rate from bottom sediment to water, and c) the radionuclide migration rate from bottom sediment to deep sediment. The estimated values of the above parameters were 6.4 x 10(-1) m s(-1), 5.7 x 10(-10) s(-1) and 5.2 x 10(-10) s(-1), respectively. These values were compared with data obtained for some Italian lakes contaminated by 90Sr after the nuclear weapons tests fallout. The relatively low radionuclide migration from water to sediment of these lakes is reflected by the values of the ratio migration velocity/migration rate from sediment to water (4 m and 12 m) that are significantly lower than the corresponding value in the Russian lake (112 m). The peculiar hydrochemical conditions of Lake Uruskul (high pH, high mineralisation, etc.) are considered to be responsible for the high radionuclide migration from water to sediment.  相似文献   
97.
98.
Chemical defense is assumed to be costly and therefore algae should allocate defense investments in a way to reduce costs and optimize their overall fitness. Thus, lifetime expectation of particular tissues and their contribution to the fitness of the alga may affect defense allocation. Two brown algae common to the SE Pacific coasts, Lessonia nigrescens Bory and Macrocystis integrifolia Bory, feature important ontogenetic differences in the development of reproductive structures; in L. nigrescens blade tissues pass from a vegetative stage to a reproductive stage, while in M. integrifolia reproductive and vegetative functions are spatially separated on different blades. We hypothesized that vegetative blades of L. nigrescens with important future functions are more (or equally) defended than reproductive blades, whereas in M. integrifolia defense should be mainly allocated to reproductive blades (sporophylls), which are considered to make a higher contribution to fitness. Herein, within-plant variation in susceptibility of reproductive and vegetative tissues to herbivory and in allocation of phlorotannins (phenolics) and N-compounds was compared. The results show that phlorotannin and N-concentrations were higher in reproductive blade tissues for both investigated algae. However, preferences by amphipod grazers (Parhyalella penai) for either tissue type differed between the two algal species. Fresh reproductive tissue of L. nigrescens was more consumed than vegetative tissue, while the reverse was found in M. integrifolia, thus confirming the original hypothesis. This suggests that future fitness function might indeed be a useful predictor of anti-herbivore defense in large, perennial kelps. Results from feeding assays with artificial pellets that were made with air-dried material and extract-treated Ulva powder indicated that defenses in live algae are probably not based on chemicals that can be extracted or remain intact after air-drying and grinding up algal tissues. Instead, anti-herbivore defense against amphipod mesograzers seems to depend on structural traits of living algae.  相似文献   
99.
It has been proposed that blue colouration in eggs has evolved as a signal of female quality that males can use to modulate their parental investment. This hypothesis is based in the antioxidant properties of biliverdin whose costly deposition in the eggshell is expected to signal female antioxidant capacity and egg quality. Since maternally derived androgens are costly to produce and may adaptively affect offspring phenotype, high-quality females may benefit by signalling their androgen investment through egg colouration. Our aim was to investigate whether egg colour variation in the spotless starling reflected the amount of pigments on the eggshell and whether egg pigmentation was related to female and egg quality. Chromatography analyses revealed that spotless starling eggshells contained two different pigments: biliverdin and protoporphyrin IX with no correlation between them. Biliverdin contents correlated positively with egg colouration indicating that darker eggs with a higher peak in the blue–green segment of the spectrum contained higher amounts of biliverdin. Eggs containing more biliverdin were laid by high-quality females and contained higher yolk testosterone levels. However, despite the strong correlation between biliverdin and colorimetric variables, egg colouration did not reflect accurately female and egg quality. Our results provide evidence that eggshell pigmentation in the spotless starling is related to female and egg quality as shown by the yolk testosterone levels. However, the lack of relation between egg colour and female condition and egg quality do not provide evidence to support the signalling function of egg colouration.  相似文献   
100.

Goal and Scope

Several studies show that the concentration of metals in mosses depends not only on metal deposition but also on factors such as moss species, canopy drip, precipitation, altitude, distance to the sea and the analytical technique used. However, contrasting results have been reported and the interpretation of the spatial variability of the metal accumulation in mosses remains difficult. In the presented study existing monitoring data from the European Heavy Metals in Mosses Surveys together with surface data on precipitation, elevation and land use are statistically analysed to assess factors other than emissions that have an influence on the metal accumulation in the mosses.

Main Features

Inference statistics and Spearman correlation analysis were applied to examine the association of the metal accumulation and the distance of the monitoring sites to the sea as well as the altitude. Whether or not significant differences of the metal loads in the mosses exist at national borders was examined with help of the U-test after Mann and Whitney. In order to identify and rank the factors that are assumed to have an influence on the metal uptake of the mosses Classification and Regression Trees (CART) were applied.

Results

No clear tendency could be derived from the results of the inference statistical calculations and the correlation analyses with regard to the distance of the monitoring site to the sea and the altitude. According to the results of the CART-analyses mainly the moss species, potential emission sources around the monitoring sites, canopy drip and precipitation have an effect on the metal bioaccumulation. Assuming that each participating country followed strictly the manual for sampling and sample preparation the results of the inference statistical calculations furthermore suggest that in most cases different techniques for digestion and analysis bias the measurements significantly.

Discussion

For the first time a national monitoring data base consisting of measurement data and metadata as well as surface information on precipitation, land use and elevation was applied to examine influence factors on the metal bioaccumulation in mosses. The respective results mirror existing knowledge from other national studies to a large extend, although further analyses are necessary to affirm the findings. These analyses should include data from other national monitoring programmes and should additionally be carried out with other decision tree algorithms than CART.

Conclusions

The local variability in the metal concentration in mosses can be uncovered in terms of predictors or underlying hidden causes by using CART. Ideally, such an approach should be applied across the whole of Europe. This will only be feasible if all participating countries provide additional information about site characteristics as currently is done in for example the German moss surveys.

Recommendations

The UNECE Metals in Mosses Survey experimental protocol should be improved in order to reduce the observed influences, to enhance standardisation, and to strengthen the quality control. This implies the integration of sampling site describing metadata into the assessment. Furthermore, basis research is needed to test the hypothesis concerning moss species-specific accumulation of depositions.

Perspectives

Provided that the presented results hold true in further analyses correction factors should be applied on the moss data in order to get the depicted spatial patterns and temporal trends of metal bioaccumulation unbiased. Such factors should be calculated for natural landscape units or ecoregions that are homogeneous with regard to climate, vegetation and altitude.  相似文献   
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