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411.
3-Hydroxy-benzo[a]pyrene (3-OH-BaP), a toxic compound with the ability to covalently bind with the macromolecules (proteins and DNA), is one of the major phenolic metabolites of benzo[a]pyrene (BaP). The purpose of this study was to evaluate the presence of 3-OH-BaP in the bile and plasma of Nile tilapia by HPLC with fluorescence detection, after waterborne exposure to BaP (10 and 100?µg?L?1). Metabolites were detected in bile and plasma, and conjugates of 3-OH-BaP (glucuronide and/or sulphate conjugates) were the majority forms in both biological fluids, glucuronide 3-OH-BaP being the main metabolite in bile. Our data suggest that extrahepatic tissues as intestine or gill are important in BaP metabolism and need to be the considered sources of metabolites released into the blood. Although, low levels of 3-OH-BaP in toxic form (free form) were detected in plasma, one cannot exclude the possibility of circulating the levels leading to adverse effects.  相似文献   
412.
Distribution of metallic constituents between soil and aerial parts of wild plants has been discussed by using relative ionic impulsions, i/I, defined as functions of concentrations of metallics ions, being i = [M]1/2M, zM the oxidation state of considered metal and I = S i the summation of contribution of metals. For this calculation metals were divided into two groups leading to I macro (K, Na, Ca, Mg, and Mn, elements accumulated in aerial parts) and to I Micro (Fe, Cu, Zn, Co and contaminants accumulated in roots). Relative ionic impulsions may be attributed to an electric potential gradient and show if an active or passive uptake is happening. For macroelements linear relationships were obtained for Mg‐K (global active uptake) and Na‐Mn‐Ca (global passive uptake) with inverse slopes. Passive ions seem to be used as counter ions for helping active assimilation. Calculated potential gradient was close to 20 mV. The same situation was found for microelements and pollutants, where Fe is taken passively helping assimilation of the rest (Cu, Zn, Co, Cd, Pb, Ni and Cr) with a potential gradient close to 13 mV. Influences of other ecological segments (rainfall, dry deposition, airborne dust and irrigation), as well as additions for amending contaminated soils are finally discussed.  相似文献   
413.
The purpose of this study was to evaluate polychlorinated biphenyls (PCBs) contamination levels in roe and red deer from north-western Poland and to assess environmental pollution in this area. A quantitative analysis was conducted using a capillary gas chromatography/mass spectrometry method. The mean concentrations of ΣPCBs (sum of PCBs: 28, 52, 101, 138, 153, 180) in liver samples were 30.24±12.35 ng·g?1 of lipid weight (l.w.) in roe deer and 60.13±14.23 ng·g?1 l.w. in red deer, compared with 24.21±10.02 and 45.22±9.77 ng·g?1 in the lungs of roe and red deer, respectively. PCBs 138, 153 and 180 were the dominant congeners in the liver samples of the analysed animals, whereas PCB 138 and 153 in the lungs. TEQs levels calculated for only dioxin-like PCBs were low: 0.32 and 0.29 pg WHO-PCB-TEQ·g?1 fat in liver of red deer and roe deer, respectively. The mean PCB concentrations obtained in our study for organs of roe deer and red deer were several times lower than those reported elsewhere. These findings show that the investigated roe and red deer originated from an area with low levels of PCB contamination.  相似文献   
414.
Nitrogen inputs to coastal environments can considerably alter the abundance of primary producers. However, how herbivores modify their trophic signatures and adjust to changes in food resource conditions remains controversial. Here, we assess the effect of nutrient availability on the diet shifts of the two main Mediterranean herbivores, the Sparid fish Sarpa salpa L. and the sea urchin Paracentrotus lividus (Lmk.) that feed mostly on the seagrass Posidonia oceanica L. (Delile), epiphytes and benthic macroalgae. To do this, we (1) investigate the patterns of isotopic composition (δ13C and δ15N signatures) of the two herbivores and their potential food sources in three areas of contrasting nutrient conditions and, (2) we assess the diet shift along this nutrient gradient by estimating the isotopic nutrient enrichment (i.e., the contribution of δ13C and δ15N signatures in consumers’ tissues relative to potential food sources). Food web signatures of δ13C were similar among the three study sites, and no patterns of δ13C shift were observed in their diets. In contrast, there was a consistent increase in N contents and δ15N along the nutrient gradient for all primary producers and their consumers. The rate of δ15N enrichment was also clearly distinctive between the two herbivores: in P. lividus it increased by 61% along the nutrient gradient, while in S. salpa it remained constant. Our results suggest that sea urchins behave as facultative omnivores and feed on vegetable or mixed diets depending on the trophic status of the system. It is unclear, however, if this modification is behavioral or the consequence of mere changes in the availability of food items, as animal epiphytes (e.g., hydrozoans, bryozoans and ascidians) can also became more abundant on seagrass leaves under increased nutrient conditions. In contrast, adult fish appear to feed on vegetal material independent of nutrient availability in the ecosystem.  相似文献   
415.
In April-May 2004, the World Health Organization (WHO) implemented, with local authorities, United Nations (UN) agencies and non-governmental organisations (NGOs), an early warning system (EWS) in Darfur, West Sudan, for internally displaced persons (IDPs). The number of consultations and deaths per week for 12 health events is recorded for two age groups (less than five years and five years and above). Thresholds are used to detect potential outbreaks. Ten weeks after the introduction of the system, NGOs were covering 54 camps, and 924,281 people (IDPs and the host population). Of these 54 camps, 41 (76%) were reporting regularly under the EWS. Between 22 May and 30 July, 179,795 consultations were reported: 18.7% for acute respiratory infections; 15% for malaria; 8.4% for bloody diarrhoea; and 1% for severe acute malnutrition. The EWS is useful for detecting outbreaks and monitoring the number of consultations required to trigger actions, but not for estimating mortality.  相似文献   
416.
This work, on the ashes from the wastewater treatment plant of Galindo (Vizcaya, Spain), has been outlined with the purpose of finding their physico-chemical properties and suggesting possible applications. Ashes contain important quantities of iron, calcium, silica, alumina and phosphates. X-Ray diffraction data make it possible to estimate the mineralogical compositions of the original ashes and also, after thermal treatment at 1200 and 1300 degrees C, the main reactions occurring in thermal treatment. Particle size analysis makes it possible to classify ashes as a very fine powdered material. The thermal treatment leads to a densification of the material and provokes losses of weight mainly due to the elimination of water, carbon dioxide and sulphur trioxide. Application tests show that ashes are not suitable for landfill and similar applications, because of their plastic properties. Testing for pozzolanic character, after the ashes had been heated at 1200 degrees C, did not lead to a strong material probably due to low contents in silica and alumina or to requiring a higher heating temperature. Thermal treatment leads to densification of the material with a considerable increase of compressive strength of the probes. The use of additives (clays and powdered glass) to improve ceramic properties of ashes will be the aim of a future work.  相似文献   
417.
Sánchez L  Romero E  Peña A 《Chemosphere》2005,59(7):969-976
Photodegradation studies of the organophosphorous insecticide methidathion in thin layers of wet soil samples have been carried out under solar irradiation. Soil samples consisted of an agricultural soil added with two amendments: a municipal biosolid and the cationic surfactant TDTMA (tetradecyl trimethyl ammonium bromide). Dark controls of the different soil treatments were also considered. Soil and biosolid samples were previously autoclaved to eliminate biotic degradation. In this study we investigated the role of these amendments in methidathion photodegradation which is a rapid (<7 days) and indirect process. Although scarce differences were found between non-amended and amended samples, methidathion from soil exposed under sunlight is degraded more quickly than in dark conditions. Photodegradation products (methidathion oxon GS 13007 and GS 12956) were not detected.  相似文献   
418.
This work presents research results on the evaluation of environmental effects of utilizing chromic waste in chromium compound production processes. The comprehensive evaluation of three chromium compound production models takes into consideration the total cumulated hazard coefficients. The implementation of the new chromium compound production model into industrial practice in 1999 allows the hazard to the natural environment to decrease by 75% in relation to the hazard caused by the old production model used until 1995. The coefficient of the target chromium compound production model was 199%, much higher than 100%. This results from the negative values of the total cumulated hazard coefficients for those cases where the sodium chromate production unit could be a big "consumer" of chromic waste.  相似文献   
419.
An incineration test program was conducted at the U.S. Environmental Protection Agency's Incineration Research Facility to evaluate the potential of incineration as a treatment option for contaminated soils at the Baird and McGuire Superfund site in Holbrook, Massachusetts. The purpose of these tests was to evaluate the incinerability of these soils in terms of the fate of arsenic and lead and the destruction of organic contaminants during the incineration process. The test program consisted of a series of bench-scale experiments with a muffle furnace and a series of incineration tests in a pilot-scale rotary kiln incinerator system. The study reported in this paper was funded by the Environmental Protection Agency under Contract 68–C9–0038 to Acurex Corporation. It has been subjected to the Agency's review and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.  相似文献   
420.
This contribution deals with the use of different sources of data (field surveys with total station and GPS, air photographs and topographic maps) as well as their integrated digital treatment in a GIS context to quantify the morphological changes in a ridge of coastal dunes in the southwest of Spain. The results show very high and increm enting rates of foredune retreat significant losses of foredune surface and a clear negative sedimentary balance (lowering and inland migration) in its recent evolution (1979–1996). Two processes can explain this evolution: (1) marine erosion and (2) the reactivation of aeolian deflation. The combined use of GPS (code/phase) and soft-copy photogrammetry seem to provide the best for monitoring future changes.  相似文献   
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