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11.
Skuterud L Gaare E Eikelmann IM Hove K Steinnes E 《Journal of environmental radioactivity》2005,83(2):231-252
Transfer of 137Cs in the soil-plant/lichen-reindeer food chain was studied in central (?stre Namdal) and southern Norway (V?g?) during 2000-2003. Reindeer from these areas have been continuously subjected to countermeasure application since the 1986 Chernobyl accident. In both areas no decline in 137Cs concentrations was detectable in reindeer slaughtered in autumn since 1995, or in reindeer slaughtered in winter since 1998-1999. Seasonal differences in 137Cs concentrations in reindeer have been less pronounced in recent years, with 137Cs concentrations occasionally higher in autumn than in winter. Soil-to-plant 137Cs transfer was significantly higher in ?stre Namdal than in V?g?. Climatic influences on lichen growth and abundance, and on soil properties that influence the availability of 137Cs for plant uptake, are hypothesized to have a larger impact on long-term transfer of radiocaesium in the soil-plant/lichen-reindeer food chain than has been previously observed. 相似文献
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Recently there has been anincreased environmental concern in severalcountries in Europe, in particular in Sweden andin the Netherlands regarding the amount of copperand zinc that is released from building materialsinto society. Due to lack of runoff data, thelegislators have so far used corrosion ratesmeasured during the last 20 years to calculatequantities of metal released from buildingsassuming that the quantity of metal corrosionequals the quantity of metal runoff. Withdecreasing levels of environmental pollutantsduring the last decade in Europe, it is importantto determine more recent and hence morerepresentative corrosion and runoff rates to beused in the calculations. For this reason a field exposure program was implemented during 48 weeks in an urbanatmosphere in Sweden determining corrosion andrunoff rates for copper and zinc of differentage. New copper exposed for 48 weeks in the urbanatmosphere shows a corrosion rate of 6.7gm-2y-1 and an almost constant runoff rate of1.3 gm-2y-1 during the period. Therunoff rate is significantly lower than thecorrosion rate and represents only a fraction(20%) of the total amount of corroded metalduring this period. Zinc shows a graduallydecreasing corrosion rate with time being 5.0gm-2y-1 after 48 weeks of exposure. Therunoff rate is relatively stable with an averagerate of 3.1 gm-2y-1 during the sameperiod. This value represents 60% of the totalamount of corroded zinc. The effect of panel age has been investigatedin parallel field and laboratory studies. Theresults show that naturally aged copper exhibitssomewhat higher average runoff rates (2 gm-2y-1) than new copper, probably due to acombined effect of storage and weatherconditions. No significant difference in runoffrate can be found between new and naturally agedzinc. The field and laboratory investigationsshow that precipitation rate and amount influence the magnitude of the runoff rate forboth copper and zinc. 相似文献
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Karlén C Wallinder IO Heijerick D Leygraf C 《Environmental pollution (Barking, Essex : 1987)》2002,120(3):691-700
The release of copper, induced by atmospheric corrosion, from naturally patinated copper of varying age (0 and 30 years) has been investigated together with its potential ecotoxic effect. Results were generated in an interdisciplinary research effort in which corrosion science and ecotoxicology aspects were combined. The aim of the investigation was to elucidate the situation when copper-containing rainwater leaves a roof in terms of runoff rate, chemical speciation, bioavailability and ecotoxicity effects. Data have been collected during a three-year field exposure conducted in the urban environment of Stockholm, Sweden. The potential environmental effects have been evaluated using a combination of a copper specific biosensor test with the bacterium Alcaligenes eutrophus and the conventional 72-h growth inhibition test with the green alga Raphidocelis subcapitata. The results show annual runoff rates between 1.0 and 1.5 g/m2 year for naturally patinated copper of varying age. The runoff rate increased slightly with patina age, which mainly is attributed to the enhanced first flush effect observed on thicker patina layers. The total copper concentration in investigated runoff samplings ranged from 0.9 to 9.7 mg/l. Both computer modeling and experimental studies revealed that the majority (60-100%) of released copper was present as the free hydrated cupric ion, Cu(H2O)6(2+), the most bioavailable copper species. However, other copper species in the runoff water, such as, e.g. Cu(OH)+ and Cu2(OH)2(2+), were also bioavailable. The copper-containing runoff water, sampled directly after release from the roof, caused significant reduction in growth rate of the green alga. It should be emphasized that the results describe the runoff situation immediately after release from the copper roof and not the real environmental ecotoxicity. Therefore the data should only be used as an initial assessment of the potential environmental effect of copper runoff from building applications. Future risk assessments should also consider dilution effects of copper, changes in its chemical speciation and bioavailability during environmental entry, and type and sensitivity of the receiving ecosystem. 相似文献
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Metal release rates from stainless steel grade 316L were investigated in artificial lysosomal fluid (ALF), simulating a human inflammatory cell response. The main focus was placed on release rates of main alloying elements using graphite furnace atomic absorption spectroscopy, and changes in surface oxide composition by means of X-ray photoelectron spectroscopy. To emphasise that alloys and pure metals possess totally different intrinsic properties, comparative studies were performed on the pure alloying constituents: iron, nickel and chromium. Significant differences in release rates were observed due to the presence of a passive surface film on stainless steel. Iron and nickel were released at rates more than 300 times lower from the 316L alloy compared with the pure metals whereas the release rate of chromium was similar. Iron was preferentially released compared with nickel and chromium. Immersion in ALF resulted in the gradual enrichment of chromium in the surface film, a small increase of nickel, and the reduction of oxidized iron with decreasing release rates of alloy constituents as a result. As expected, released metals from stainless steel grade 316L were neither in proportion to the bulk alloy composition nor to the surface film composition. 相似文献
16.
Midander K Wallinder IO Leygraf C 《Environmental pollution (Barking, Essex : 1987)》2007,145(1):51-59
The aim of this paper is to provide quantitative data on copper release from powder particles of different copper materials, including artificial copper patina, Cu(2)O and metallic Cu, when exposed to different synthetic biological media to simulate an inhalation scenario and/or skin contact. Generated data may contribute in risk assessment of potential health effects following exposure to and handling of various copper materials. All tests were performed in vitro to determine total copper concentrations, release rates of total copper, and to elucidate its time-dependence. The copper release process was interpreted in terms of specific surface area, surface morphology-, and composition. All powder materials show a time-dependent release process with total copper release rates less than 3 microg/cm(2) per hour at steady state conditions, for all media investigated. The importance of using relevant test media when simulating different interstitial lung conditions and difficulties encountered when comparing powder particles of essentially different properties are thoroughly discussed. 相似文献
17.
The aim of this study was to examine the effects of litter size and parity on sibling competition, piglet survival, and weight
gain. It was predicted that competition for teats would increase with increasing litter size, resulting in a higher mortality
due to maternal infanticide (i.e., crushing) and starvation, thus keeping the number of surviving piglets constant. We predicted
negative effects on weight gain with increasing litter size. Based on maternal investment theory, we also predicted that piglet
mortality would be higher for litters born late in a sow's life and thus that the number of surviving piglets would be higher
in early litters. As predicted, piglet mortality increased with increasing litter size both due to an increased proportion
of crushed piglets, where most of them failed in the teat competition, and due to starvation caused by increased sibling competition,
resulting in a constant number of survivors. Piglet weight at day 1 and growth until weaning also declined with increasing
litter size. Sows in parity four had higher piglet mortality due to starvation, but the number of surviving piglets was not
affected by parity. In conclusion, piglet mortality caused by maternal crushing of piglets, many of which had no teat success,
and starvation caused by sibling competition, increased with increasing litter size for most sow parities. The constant number
of surviving piglets at the time of weaning suggests that 10 to 11 piglets could be close to the upper limit that the domestic
sow is capable of taking care of. 相似文献
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Modelling and mapping of copper runoff for Europe 总被引:1,自引:0,他引:1
A predictive runoff rate model for copper has been refined and used to generate copper runoff maps for Europe. The new model is based on laboratory and field runoff data and expresses the runoff rate R (g m(-2) yr(-1)) through two contributions, both with a physical meaning: R = (0.37SO(0.5)(2) = 0.96 rain10(-0.62 pH) (cos(theta)/cos(45 degree)). Input parameters are the SO(2) concentration (microg m(-3)), pH, amount of rain (mm yr(-1)), and surface angle of inclination (theta). The first contribution originates from dry periods between rain events (the first-flush effect) and the second from the rain events. The dry term has been refined in comparison to the original model by assuming a mass balance between measured corrosion mass loss, calculated copper retention in the patina and predicted copper runoff. The refined model predicts 76% of all reported runoff rates, worldwide, within 35% from their measured value. This includes sites with low SO(2) concentration, where the original model erroneously predicted higher runoff rates than corrosion rates. Based on environmental data from the EMEP programme for the years 1980-2000, the new model has been used to derive runoff rate maps for Europe with 50 x 50 km grid resolution. The runoff mapping shows a substantial reduction in runoff rate over the investigated time period, and with copper runoff rates now generally less than 2 g m(-2) yr(-1). 相似文献
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In Spring 2015, a series of earthquakes and aftershocks struck Nepal. The earthquakes caused significant changes in labor and land availability, cash income needs, and land quality. We examine how these post-earthquake impacts converged with ongoing agricultural shifts. Earthquake-related socio-economic and landscape changes specifically motivate the adoption of cardamom, Amomum subulatum, a high-value ecologically beneficial, and low labor commercial crop. We investigate reasons for the increased interest in cardamom post-earthquake, and challenges associated with it. We find that adopting cardamom serves as an important post-disaster adaptation. However, more broadly, unevenly distributed interventions coupled with the high capital costs of agricultural transition exacerbate social differentiation in communities after the disaster. Adoption is often limited to economically better off smallholder farmers. This paper extends previous research on disasters and smallholder farming by highlighting the specific potential of disasters to accelerate agricultural transitions and resulting inequality from the changes. 相似文献