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371.
Commercial and recreational harvesting of shellfish within the coastal systems is usually very extensive. Since these ecosystems are frequently subjected to contamination, namely from agricultural, urban and industrial activities, and shellfish generally display a high capacity to bioaccumulate metals, populations may be at risk in terms of toxic metal exposure as a consequence of the harvesting and ingestion of near shore coastal marine organisms. Shellfish is regularly tested for concentrations of metals and other contaminants by legal authorities for commercial purposes, but although health officials use total metal as standards of food safety, only a part of the metal accumulated in shellfish is available to be assimilated and to cause toxic effect. In order to elucidate these issues an investigation on cockles inhabiting the Aveiro estuary was conducted. Element levels in sediments and wild Cerastoderma edule from sampling areas with different levels of contamination were measured; total element burden of cockles was related to accessible fraction for assimilation (TAM); element concentrations in wild C. edule were compared to EFSA (European Food Safe Authorities), USFDA (United States Food and Drug Administration) and FSANZ (Food Standards Australia and New Zealand) maximum levels (MLs); and the amount of cockle flesh needed to be consumed to exceed provisional tolerable weekly intake (PTWI) was determined. The present work showed that although sediment metal and metalloid contamination in Aveiro estuary is low the concentration of elements in C. edule does not reflect the contamination of the sediment. Aluminium (Al) and mercury (Hg) were the less and nickel (Ni), lead (Pb), zinc (Zn) and cadmium (Cd) were the most bioaccumulated metals by cockles. Comparison of MLs from international organisations with the concentration of elements in C. edule showed that arsenic (As) and Pb exceeded standard levels. The ingestion of less than 1 kg for As and 1.5 kg for Pb of cockles would result in exceeding the PTWI threshold (0.015 and 0.025 mg kg?1 week?1 respectively) in any of the areas considered in the study. Cd and Al also appear to be limiting elements for human consumption. Indeed, consumption of more than 3.1 kg and 2.1 kg of whole cockle soft part from one of the study areas during a single week would lead to exceedance of the recommended PTWI value for Cd (0.007 mg kg?1 week?1) and Al (7 mg kg?1 week?1) respectively. The health concerns to humans from cockle consumption from Aveiro estuary are discussed.  相似文献   
372.
Non-Urbanised Areas (NUAs) are part of agricultural and green infrastructures that provide ecosystem services. Their role is fundamental for the minimization of urban pollution and adaptation to climate change. Like all natural ecosystems, NUAs are endangered by urban sprawl. The regulation of sprawl is a key issue for land-use planning. We propose a land use suitability strategy model to orient Land Uses of NUAs, based on integration of Land Cover Analysis (LCA) and Fragmentation Analysis (FA). With LCA the percentage of evapotranspiring surface is defined for each land use. Dimensions and densities of NUAs patches are assessed in FA. The model has been developed with Geographical Information Systems, using an extensive set of geodatabases, including orthophotos, vectorial cartographies and field surveys. The case of the municipality of Mascalucia in Catania metropolitan area (Italy), characterized by a considerable urban sprawl, is presented.  相似文献   
373.

Background

Little evidence is available on the influence of socioeconomic factors on exposure to persistent organic pollutants, especially during vulnerable periods such as pregnancy and early life.

Objective

To investigate the relationship of maternal social class with placental concentrations of organochlorine pesticides (OCPs) and their combined estrogenic activity measured with a biomarker of exposure.

Methods

Exposure to 16 OCPs (DDTs, endosulfans, and seven other compounds) and the total effective xenoestrogenic burden (TEXB) were analyzed in placentas from a mother-child cohort. OCP concentrations were quantified by gas chromatography and mass spectrometry, and TEXB was assessed with the E-Screen bioassay. Social class was classified according to maternal occupation. Multivariate regression analysis was conducted to examine variations in pesticide exposure and TEXB as a function of maternal social class in 257 subjects.

Results

Placental p,p′-DDT concentrations were higher in social classes III and IV than in classes I-II (the most affluent); concentrations of the sum of DDTs were higher in class IV; and exposure to the sum of endosulfans was greater in class III. HCB concentrations were higher among women in class IV than in classes I-II and among manual (classes III-V) than non-manual workers. However, the trend across social classes was only statistically significant for HCB. Social class significantly explained 10% of the variability in concentrations of the sum of endosulfans.

Conclusion

There is a need to explore whether more disadvantaged populations suffer higher levels of exposure to pesticides or other environmental chemicals and how different social processes contribute to this exposure.  相似文献   
374.
Cestone A  Di Natale M  De Rosa S 《Chemosphere》2008,71(8):1440-1445
The main objective of this study, within development of engineering solutions for coastal areas depuration, was to establish the role of the benthic macro-organisms in the biodegradation of the detergents in marine environment and to estimate the toxicity of these substances for a particular marine species: the ascidian Styela plicata. The experimental studies undertaken in aquarium with seawater enriched in a pure lynear alkylbenzene sulfonate (LAS), the 1-(p-sulfophenyl)nonane (1C9-LAS), showed that the degradation was two times more fast in presence of the S. plicata, than of the only marine bacteria. The toxicity of this pollutant was also determined. This study demonstrates that the ascidia S. plicata can be a potential biomediator for the surfactant 1C9-LAS, and it can be used to design a pilot project, to bioremediate harbours and the coastal areas interested from the urban pollution.  相似文献   
375.
Reboreda R  Caçador I 《Chemosphere》2007,69(10):1655-1661
Total concentrations and fractionation of Cu, Zn and Pb in seven operationally defined phases (exchangeable, carbonates, manganese oxides, organic complexes, amorphous iron oxides, crystalline iron oxides and residual) were determined in sediments colonised by the halophyte species Halimione portulacoides and Spartina maritima in a Tagus estuary salt marsh (Portugal). We aimed to determine whether the speciation of these metals was different in areas colonised by each halophyte. Higher concentrations of Cu, Zn and, in particular Pb, were found in the rhizosphere of S. maritima than in the root sediments of H. portulacoides. Geochemical fractionation of Cu, Zn and Pb in sediments of the salt marsh depended upon the metal, and for Zn and Pb clearly varied with depth and with the colonising species. The higher redox potential observed in sediments colonised by H. portulacoides may in part explain the observed differences in the speciation of Cu, Zn and Pb.  相似文献   
376.
This study was undertaken to evaluate the degradation and mobility of the herbicide tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N'-dimethylurea) in soil under field conditions, and its potential for leaching and groundwater contamination. A watershed, Espraiado, located over a recharge area in Brazil, was chosen for soil and water studies. At Espraiado, water samples were collected from seven wells at intervals of three months from March 2004 to June 2006 and analyzed for tebuthiuron. Other samples were taken from city wells located outside of the recharge area. To assess the potential movement to the aquifer, tebuthiuron was also applied to trial plots at the recommended label rate of 1.0 kg/ha a.i. in May of 2004, with and without sugarcane coverage, on sandy soil. Soil samples were collected during the years of 2004 and 2005, at depths intervals of 20 cm from soil surface down to 120 cm and analyzed for tebuthiuron at zero, 3, 30, 60, 90, 120, 150, 180, 240, and 300 days after application. There was no clear effect of sugarcane coverage on the tebuthiuron degradation in soils, but it moved faster into the soil where there was no cover. After 180 days there were no measurable residues in the soil, and tebuthiuron was not found below 40 cm depth in any time. Tebuthiuron had a half-life of 20 days under those conditions. No tebuthiuron residue was found in ground water samples at any sampling time.  相似文献   
377.
Journal of Polymers and the Environment - Cellulose nanopaper (CNP) is a new potential candidate for flexible biopolymer substrate made of nanocellulose (NC). We systematically studied the effect...  相似文献   
378.
Journal of Polymers and the Environment - There is a scientific consensus that the use of membranes for water filtration presents itself as a promising research area for removing a wide range of...  相似文献   
379.
Food and Environmental Virology - Hepatitis E virus (HEV) is responsible for acute hepatitis in humans, through foodborne, zoonotic, and waterborne transmission routes. This study aimed to assess...  相似文献   
380.
Environmental Science and Pollution Research - In this study, we evaluated indoor air quality to highlight the effects of environmental pollution in the field of cultural heritage. In particular,...  相似文献   
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