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Are concentrations of mercury, cadmium and lead in Antarctic organisms a reliable baseline for global biomonitoring networks?
No full textEnvironmental factors promoting the bioaccumulation of Cd and Hg in Antarctic marine and terrestrial organisms
No full textBiomagnification of mercury in an Antarctic marine coastal food web
No full textTotal Hg concentrations were determined in marine sediments and biota from the inner shelf of Terra Nova Bay (Antarctica). Like published data on air, snow and soils from the same region, Hg levels in the finest fraction of marine sediments were among the lowest ever reported for coastal marine environments (0.012 ± 0.007 μg g-1 dry wt). A progressive increase in Hg concentrations was found in organisms at different levels of the marine food web (phytoplankton < zooplankton and benthic primary consumers < detritivorous and opportunistic benthic invertebrates < epipelagic fish < demersal fish and plankton-feeding seabirds < fish-eating penguins < predatory birds and Weddell seal). In general, primary producers and consumers showed slightly lower Hg concentrations (0.076 ± 0.023 μg g-1 dry wt) than organisms of related species from other seas, but values in feathers (2.91 ± 1.93 μg g-1 dry wt) of the Antarctic skua and in tissues of a Weddell seal (44.0 and 24.0 μg g-1 dry wt in the liver and spleen, respectively) were similar to those in skuas and seals from the northern hemisphere. Trophic connections between organisms in well developed benthic communities, phytoplankton and fish and environmental factors such as enhanced upwelling of cold water, sea ice and low light are deemed to enhance natural biomagnification processes of Hg in the pristine Antarctic coastal environment
Mercury, cadmium and lead accumulation in Antarctic mosses growing along nutrient and moisture gradients
No full textAccumulation of Hg, Cd and Pb by moss was studied in a coastal ice-free area (Edmonson Point, northern Victoria Land) in relation to the water and nutrient availability and substratum characteristics. Although metal concentrations in surface soils were among the lowest ever reported from remote areas, those of Hg and Cd in mosses were higher, being in the same range as those usually reported in regional surveys in the northern hemisphere. By contrast, Antarctic mosses showed very low Pb concentrations, and no impact from local human activities was detected. Marine aerosols, seabird guano and volcanic emissions appeared to be the more probable sources of Cd and Hg. Besides atmospheric deposition, the main pathway of metals to mosses was probably through evapo-transpiration at their surface which determines an upward migration of ions and their bioaccumulation
La biomagnificazione del mercurio nelle catene trofiche costiere di Baia Terra Nova (Antartide)
No full textBaseline concentrations of elements in the Antarctic macrolichen Umbilicaria decussata
No full textTotal concentrations of major and trace elements were determined in samples of the epilithic lichen Umbilicaria decussata from 24 ice-free areas in coastal Victoria Land (Antarctica). Overall average concentrations of trace elements except Cd were the lowest ever reported for lichens of the genus Umbilicaria. Specifically, the mean level of Pb in lichens from granitic rocks (0.46 ± 0.18 μg g-1 dry wt) was more than four times lower than the lowest record in Arctic lichens. No impact of local human activities was detected, but the elemental composition of U. decussata was affected by entrapment of soil or rock dust particles and probably by uptake of soluble elements from substrate. Relationships between elements and their distribution patterns in the study area indicated that the marine environment is the main source of major ions and perhaps of Cd in lichens. Accumulation of P was detected in samples from coastal sites frequented by seabirds. Although the present results can be taken as baseline levels of major and trace elements in Antarctic U. decussata from substrates with very different geochemical features, further research is necessary to evaluate the relative element contribution from each substrate with respect to those from snow, marine aerosol, salt encrustations and guano
Environmental factors promoting bioaccumulation of Hg and Cd in Antarctic marine and terrestrial organisms
No full textContinental Antarctica is almost unaffected by long-range atmospheric transport ofheavy metals and
contlIDination due te human activities has only been detected in very localised areas. Concentrations
ofmetals in most abiotic environmental matrices are therefore among the lowest in the world. Despite
these pristine environmental conditions, lichens, mosses and several anitnal taxa dominating coastal
marine ecosystems of northern Victoria Land (continentaf Antarctica) .show surprisingly high
concentrations of cadmium and mercury (i.e. similar to or higher than those measured in related .
species in the northern hemisphere). Besides the slow growth rate (Le. long exposure time) and other
ecophysiological characteristics ofAntarctic organisms, environmental factors such as upwelling of
deep marine waters and ice-cover are presumably involved in the bioaccumulation of cadmium and
mercury. These metals from the marine environment also reach cryptogarns in coastal ice-free areas
through marine aerosol, seabird guano and snow precipitation. In coastal marine ecosystems, food
webs are much more complex than the krill system in oceano waters. The involvement of benthic
organisrns lengthens the chains and enhances the biomagnification of mercury (plankton < benthic
invertebrates < demersal fish < fish-eating birds and mammals)
Ecological studies on fish of commercial importance as bioindicators of Adriatic food chain contamination
No full textPreliminary data on butyltin residues in dolphins frequenting the Mediterranean coastal areas
No full textCarbon nanomaterial functionalization with pesticide-detoxifying carboxylesterase
Full text linkFour carbon materials, spent coffee-ground biochar, carbon black, short CNTs, and nitrogen-doped few-layer graphene (N-graphene) were tested for their functionalization with a commercial carboxylesterase. Their robustness to variations in time and key physicochemical parameters (temperature and pH) was analysed. In general, carbon nanomaterials showed better performance than biochar, both in terms of binding capacity and resilience in harsh conditions, at statistically significant levels. Among the tested materials, functionalized N-graphene also showed the highest level of inhibition of carboxylesterase by pesticide exposure. Therefore, N-graphene was selected for biotechnological application of pesticide scavenging toxicity in T. thermophila, a ciliate bioindicator of water quality. While immobilization of the enzyme was not effective in the case of carbaryl, a methyl carbamate, in the case of the organophosphorus dichlorvos, a 1- or 30-min contact time with a water solution containing 5 times the LC100-0.5 mM - allowed 50% and 100% rescue of ciliate survival, respectively. These results suggest that functionalization with carboxylesterase may be of additional benefit compared to bare carbon in water clean-up procedures, especially for highly hydrophilic pesticides such as dichlorvos
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