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931.
The atmospheric transport of volcanic products are subject to several variables, mainly the height of the eruption column and wind direction, thus elements associated with the ashes are deposited in major or lesser degree depending on variables as latitude, wind and humidity. The lichens are able to reflect the atmospheric fallout. The present work evaluated the correlation between meteorological parameters, geographic locations, sulphur and other element concentrations in lichens genus Usnea affected by Puyehue–Cordón Caulle complex (North Patagonia Andean Range) eruption of June 4, 2011. Semiquantitative analyses of biological elements by scanning electron microscope methods, sulphur (S) by LECO and other elements by instrumental neutron activation were evaluated by principal component analysis. Elements as antimony, arsenic, barium, bromine, calcium, caesium, potassium, rubidium, selenium, and uranium correlated with distance to volcano, also calcium and potassium with longitude while bromine, rubidium, and potassium with humidity. Those results indicate that Usnea sp. is a good bioindicator of the atmospheric volcanic emissions in relation to environmental gradient.  相似文献   
932.
Aquatic environmental pollution may cause biodiversity loss. Thus, monitoring studies are very important because fish health reflects both quality and sustainability of the environment, as well as of the individuals that live there. In the present report, genetic biomarkers (piscine micronucleus test; comet assay with blood, liver, and kidney cells) were used in specimens of Astyanax sp. to analyze the contamination level of the Cangüiri Farm through biomonitoring. The Cangüiri Farm, the old school farm of the Federal University of Paraná, is inside the Iraí River Environment Preservation Area, created in 1996 to preserve the sources of public water supply in Curitiba and metropolitan area. We verified that the fishes collected within the Cangüiri Farm area presented high damage levels, showing more environment contamination when compared to the specimens collected in the Costa Ecologic Park, used as reference in the present report. The results indicate that the Cangüiri Farm, which is inside an environment protection area, created especially for the protection of the fountainhead for water supply, may be contaminated. These toxic residues, which were remarkably persistent in the environment, are possibly derived from agricultural activities in the wider area. Thus, we suggest the analysis of the area with other biomarkers and for a longer time period.  相似文献   
933.
The Ethiopian Rift Valley Lakes host populations of edible fish species including Oreochromis niloticus, Labeobarbus intermedius and Clarias gariepinus, which are harvested also in other tropical countries. We investigated the occurrence of six heavy metals in tissues of these fish species as well as in the waters of Lake Koka and Lake Awassa. Both lakes are affected by industrial effluents in their catchments, making them ideal study sites. Mercury concentrations were very low in the water samples, but concentrations in the fish samples were relatively high, suggesting a particularly high bioaccumulation tendency as compared with the other investigated metals. Mercury was preferentially accumulated in the fish liver or muscle. It was the only metal with species-specific accumulation with highest levels found in the predatory species L. intermedius. Lower mercury concentrations in O. niloticus could be attributed to the lower trophic level, whereas mercury values in the predatory C. gariepinus were unexpectedly low. This probably relates to the high growth rate of this species resulting in biodilution of mercury. Accumulation of lead, selenium, chromium, arsenic and cadmium did not differ between species, indicating that these elements are not biomagnified in the food chain. Values of cadmium, selenium and arsenic were highest in fish livers, while lead and chromium levels were highest in the gills, which could be related to the uptake pathway. A significant impact of the industrial discharges on the occurrence of metals in the lakes could not be detected, and the respective concentrations in fish do not pose a public health hazard.  相似文献   
934.
The current study investigates the potential for discolouration and degradation of Reactive Blue 19 and Reactive Black 5 textile dyes by endophytic fungi Phlebia sp. and Paecilomyces formosus as well as the potential cytotoxicity of products or by-products generated by the treatments in fish erythrocytes. It was observed at 30 days that both endophytes showed biodegradation activity with 0.1 g mL?1 of dyes. P. formosus showed highest extracellular and intracellular protein content levels after the 15th day, and Phlebia sp. stands out for production of extracellular laccase, indicating that this enzyme may be associated with the decolouration capacity. The dyes showed toxic effects in fishes at 0.01 g mL?1 concentration, resulting in the appearance of micronuclei in erythrocyte cells. When degraded dyes treated by endophytes were tested, the frequency of micronuclei reduced approximately 20%, indicating the effectiveness of these endophytic in the treatment of textile dyes with less environmental impact, thus indicating a potential for application of these fungi in bioremediation process.  相似文献   
935.
This comment highlights a whole series of datasets on thallium concentrations in the environment that were overlooked in the recent review by Karbowska, Environmental Monitoring and Assessment, 188, 640, 2016 in this journal. Geochemical surveys carried out over the last few decades all over the world at various scales and using different sampling media have reported the concentration of thallium (and dozens more elements) in tens of thousands of samples. These datasets provide a ‘real-world’ foundation upon which source apportionment investigations can be based, monitoring programs devised and modelling studies designed. Furthermore, this comment also draws attention to two global geochemical mapping initiatives that should be of interest to environmental scientists.  相似文献   
936.
Several mutagenic agents may be present in substances released in the environment, which may cause serious environmental impacts. Among these substances, there is a special concern regarding the widespread use of silver nanoparticles (AgNP) in several products due to their widely known bactericidal properties, including in the medical field and the food industry (e.g., active packaging). The assessment of the effects of AgNP released in the environment, having different concentrations, sizes, and being associated or not to other types of materials, including polymers, is therefore essential. In this research, the objective was to evaluate the genotoxic and cytotoxic effects of AgNP (size range between 2 and 8 nm) on root meristematic cells of Allium cepa (A. cepa). Tests were carried out in the presence of colloidal solution of AgNP and AgNP mixed with carboxymethylcellulose (CMC), using distinct concentrations of AgNP. As a result, when compared to control samples, AgNP induced a mitotic index decrease and an increase of chromosomal aberration number for two studied concentrations. When AgNP was in the presence of CMC, no cytotoxic potential was verified, but only the genotoxic potential for AgNP dispersion having concentration of 12.4 ppm.  相似文献   
937.
This study represents the first use of Leucozonia nassa (Mollusca-Gastropoda) in a program of long-term monitoring. Specimens of L. nassa were collected between 2006 and 2014 and analyzed for the occurrence of imposex in two areas in Southeastern Brazil, one control area and another characterized by the presence of many ports and marinas. Imposex was evaluated in nine sites based on the percentage of females exhibiting imposex (I%), relative penis length index and vas deferens sequence index, classical indices to evaluate tributyltin (TBT) impacts. Moreover, this study uses for the first time in a tropical environment the ecological quality ratio (EQR), an approach to verify the imposex levels as an indicator of the impact by organotin compounds according to the EU Water Framework Directive. The results confirm the occurrence of high levels of imposex in L. nassa with all the indices evaluated. Furthermore, the results also indicate that, despite the international ban, antifouling paints based on TBT are still possibly used in Brazil. In addition, this study shows that L. nassa has the characteristics that make it a suitable bioindicator to monitor TBT pollution, and that the use of the EQR may create important data regarding this problem.  相似文献   
938.
Nucella lapillus (L.) is a marine gastropod mollusc widely used as a bioindicator of TBT pollution in the North Atlantic coastlines. The species reproductive cycle and the male penis length seasonal/spatial variation were studied at a single site at Aveiro seashore (NW Portugal) between December 2005 and June 2007. The main objective of this work is to assess if the "Relative Penis Size Index" (RPSI)--an important imposex assessment index--varies seasonally and spatially in the same sampling site and how this can affect results obtained in imposex monitoring programmes. Animals able to reproduce were found every month but a seasonal pattern in N. lapillus reproductive cycle was evident. Female gametogenic maturation varied seasonally and a decrease in capsule gland volume and condition factor occurred in late summer/early autumn. The gametogenesis in males did not show a significant seasonal variation as in females but the condition factor, penis length, amount of sperm and prostate volume also diminished in late summer/early autumn. On the other hand, males that were close to egg capsules clusters had larger penises than those far away from clusters. The temporal and spatial male penis length variation introduces a bias on imposex assessment results when using RPSI and the magnitude of the error involved is evaluated for different TBT pollution levels scenarios. We consider that RPSI provides interesting and complementary information that should not be excluded from monitoring programmes, but temporal or spatial comparisons of imposex should be based on other more reliable imposex indices like the VDSI.  相似文献   
939.
Pasture selection by livestock is an essential topic for rangeland management, especially in trace element-contaminated soils. We have studied the composition (nutrients and trace elements) of a grass-based diet from soils affected by a mine spill at different growth stages (October 2008 to May 2009). A diet based on other plants (mainly Compositae species) was also studied (May 2009) for comparison. Faeces and mane hair of horses feeding on these pastures were also analysed. Micronutrient (Cu, Fe, Mn and Zn) and potentially toxic trace element (As, Cd, Pb, Tl) concentrations were below the maximum tolerable levels (MTL) for horses, except for Fe (at early growth of pastures) and Cd (in the diet based on ‘other’ plants). Values of potential ingestion of Fe by horses were higher than 10 mg kg body weight − 1 day − 1. Cadmium concentrations in some pasture samples (those composed of Compositae species) were higher than 3 mg kg − 1. Potential toxicity of such Cd levels in pastures is uncertain, since a high disparity of criteria about MTL by cattle exists (between 0.5 and 10 mg kg − 1 diet). Nutrient concentrations were adequate for horses, which could counteract possible harmful effects derived from trace element ingestion. The analyses of excreta and mane hair point to the low risk of toxicity derived from the consumption of these contaminated pastures. However, the ingestion of regenerating pastures (autumnal samples) should be avoided due to the greater risk of ingestion of contaminated soil attached to the plant material. Management of these pastures by grazing requires periodic monitoring. Special attention should be given to Fe and particularly Cd (non-essential element) which accumulates in animal organs, where it could provoke uncertain long-term effects.  相似文献   
940.
Multimedia mass balance models differ in their treatment of spatial resolution from single boxes representing an entire region to multiple interconnected boxes with varying landscape properties and emission intensities. Here, model experiments were conducted to determine the relative importance of these two main factors that cause spatial variation in environmental chemical concentrations: spatial patterns in emission intensities and spatial differences in environmental conditions. In the model, experiments emissions were always to the air compartment. It was concluded that variation in emissions is in most cases the dominant source of variation in environmental concentrations. It was found, however, that variability in environmental conditions can strongly influence predicted concentrations in some cases, if the receptor compartments of interest are soil or water—for water concentrations particularly if a chemical has a high octanol–air partition coefficient (K oa). This information will help to determine the required level of spatial detail that suffices for a specific regulatory purpose.  相似文献   
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