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961.
Considering the important role that surface waters serve for drinking water production, it is important to know if these resources are under the impact of contaminants. Apart from environmental pollutants such as pesticides, compounds such as (xeno)estrogens have received al lot of research attention and several large monitoring campaigns have been carried out to assess estrogenic contamination in the aquatic environment. The introduction of novel in vitro bioassays enables researchers to study if – and to what extent – water bodies are under the impact of less-studied (synthetic) hormone active compounds. The aim of the present study was to carry out an assessment on the presence and extent of glucocorticogenic activity in Dutch surface waters that serve as sources for drinking water production. The results show glucocorticogenic activity in the range of <LOD – 2.4 ng dexamethasone equivalents L−1 (dex EQs) in four out of eight surface waters. An exploratory time-series study to obtain a more complete picture of the yearly average of fluctuating glucocorticogenic activities at two sample locations demonstrated glucocorticogenic activities ranging between <LOD – 2.7 ng dex EQs L−1. Although immediate human health effects are unlikely, the environmental presence of glucocorticogenic compounds in the ng L−1 range compels further environmental research and assessment.  相似文献   
962.
The human diet is recognised as one possible major exposure route to the overall perfluorinated alkylated substances (PFAS) burden of the human population, resulting directly from contamination of dietary food items, as well as migration of PFAS from food packaging or cookware. Most European countries carry out national monitoring programs (food basket studies) to monitor contamination with pollutants. Usually, for PFASs, non-coordinated approaches are used in Europe, since food basket studies are mainly carried out by national authorities following national requirements and questions, making comparisons between different countries difficult. A harmonised sampling campaign collecting similar food items in a uniform procedure enabling direct comparison between different regions in Europe was designed. We selected four countries (Belgium, Czech Republic, Italy and Norway), representing the four regions of Europe: West, East, South and North. In spring 2010 and 2011, 20 different types of vegetables were sampled in Belgium, Czech Republic, Italy and Norway. Perfluorinated carboxylic acids (PFCAs) were the main group of detected PFASs, with perfluorinated octanoic acid (PFOA) as the most abundant PFCA (with exception of samples from Czech Republic), followed by perfluorinated hexanoic acid and perfluorinated nonanoic acid. Dietary intake estimates for PFOA show only low human exposure due to vegetable consumption for adults and children, mostly governed by high intake of potatoes.  相似文献   
963.
Water is fundamental to the existence of life since it is essential to a series of activities, such as agriculture, power generation, and public and industrial supplies. The residual water generated by these activities is released into the environment, reaches the water systems, and becomes a potential risk to nontarget organisms. This paper reports the development and validation of a quantitative method, based on solid-phase extraction and liquid chromatography tandem mass spectrometry, for the simultaneous analysis of 18 pharmaceuticals and personal care products (PPCPs) and 33 pesticides in surface and drinking waters. The accuracy of the method was determined by calculating the recoveries, which ranged from 70 to 120 % for most pesticides and PPCPs, whereas limits of quantification ranged from 0.8 to 40 ng/L. After the validation step, the method was applied to drinking and surface waters. Pesticides and PPCPs were found in concentrations lower than 135.5 ng/L. The evaluation of different water sources with regard to contamination by pesticides and PPCPs has been quite poor in southern Brazil.  相似文献   
964.
This study explores the possibility of using iron-loaded sepiolite, obtained by recovering iron from polluted water, as a catalyst in the electro-Fenton oxidation of organic pollutants in textile effluents. The removal of iron ions from aqueous solution by adsorption on sepiolite was studied in batch tests at iron concentrations between 100 and 1,000 ppm. Electro-Fenton experiments were carried out in an electrochemical cell with a working volume of 0.15 L, an air flow of 1 L/min, and 3 g of iron-loaded sepiolite. An electric field was applied using a boron-doped diamond anode and a graphite sheet cathode connected to a direct current power supply with a constant potential drop. Reactive Black 5 (100 mg/L) was selected as the model dye. The adsorption isotherms proved the ability of the used adsorbent. The removal of the iron ion by adsorption on sepiolite was in the range of 80–100 % for the studied concentration range. The Langmuir and Freundlich isotherms were found to be applicable in terms of the relatively high regression values. Iron-loaded sepiolite could be used as an effective heterogeneous catalyst for the degradation of organic dyes in the electro-Fenton process. Successive batch processes were performed at optimal working conditions (5 V and pH 2). The results indicate the suitability of the proposed combined process, adsorption to iron remediation followed by the application of the obtained iron-loaded sepiolite to the electro-Fenton technique, to oxidize polluted effluents.  相似文献   
965.
Bisphenol A (BPA) is an endocrine disrupting chemical (EDC) whose migration from food packaging is recognized worldwide. However, the real overall food contamination and related consequences are yet largely unknown. Among humans, children’s exposure to BPA has been emphasized because of the immaturity of their biological systems. The main aim of this study was to assess the reproductive impact of BPA leached from commercially available plastic containers used or related to child nutrition, performing ecotoxicological tests using the biomonitoring species Daphnia magna. Acute and chronic tests, as well as single and multigenerational tests were done. Migration of BPA from several baby bottles and other plastic containers evaluated by GC-MS indicated that a broader range of foodstuff may be contaminated when packed in plastics. Ecotoxicological test results performed using defined concentrations of BPA were in agreement with literature, although a precocious maturity of daphnids was detected at 3.0 mg/L. Curiously, an increased reproductive output (neonates per female) was observed when daphnids were bred in the polycarbonate (PC) containers (145.1?±?4.3 % to 264.7?±?3.8 %), both in single as in multigenerational tests, in comparison with the negative control group (100.3?±?1.6 %). A strong correlated dose-dependent ecotoxicological effect was observed, providing evidence that BPA leached from plastic food packaging materials act as functional estrogen in vivo at very low concentrations. In contrast, neonate production by daphnids cultured in polypropylene and non-PC bottles was slightly but not significantly enhanced (92.5?±?2.0 % to 118.8?±?1.8 %). Multigenerational tests also revealed magnification of the adverse effects, not only on fecundity but also on mortality, which represents a worrying trend for organisms that are chronically exposed to xenoestrogens for many generations. Two plausible explanations for the observed results could be given: a non-monotonic dose–response relationship or a mixture toxicity effect.  相似文献   
966.
A set of periurban calcareous agricultural Mediterranean soils was spiked with a mixture of Cd, Cu, Pb and Zn at two levels within the limit values proposed by current European legislation, incubated for up to 12 months, and subjected to various one-step extraction procedures to estimate mobile (neutral salts) and potentially mobile metal fractions (complexing and acidic extraction methods). The results obtained were used to study metal extractability patterns according to the soil characteristics. The analytical data were coupled with mineralogical investigations and speciation modelling using the Visual Minteq model. The formation of soluble metal-complexes in the complexing extracts (predicted by the Visual Minteq calculations) led to the highest extraction efficiency with complexing extractants. Metal extractability patterns were related to both content and composition of carbonate, organic matter, Fe oxide and clay fractions. Potentially mobile metal fractions were mainly affected by the finest soil fractions (recalcitrant organic matter, active lime and clay minerals). In the case of Pb, scarce correlations between extractable Pb and soil constituents were obtained which was attributed to high Pb retention due to the formation of 4PbCO3·3PbO (corroborated by X-ray diffraction). In summary, the high metal proportion extracted with complexing agents highlighted the high but finite capacity to store potentially mobilizable metals and the possible vulnerability of these soils against environmental impact from metal accumulation.  相似文献   
967.
The solid-solution distribution or partition coefficient (Kd) is a measure of affinity of potentially toxic elements (PTE) for soil colloids. Kd plays a key role in several models for defining PTE guideline values in soils and for assessing environmental risks, and its value depends on edaphic and climatic conditions of the sites where the soils occur. This study quantified Kd values for Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn from representative soil samples from Brazil’s eastern Amazon region, which measures 1.2 million km2. The Kd values obtained were lower than those set by both international and Brazilian environmental agencies and were correlated with the pH, Fe and Mn oxide content, and cationic exchange capacity of the soils. The following order of decreasing affinity was observed: Pb?>?Cu?>?Hg?>?Cr?>?Cd?≈?Co?>?Ni?>?Zn.  相似文献   
968.
The rollback or proportional model is widely used in pollution control calculations and included in the guidelines for preparing and evaluating state implementation plans. Its basis and limitations are not widely known or understood. In this paper, the basis and limitations of rollback are listed and discussed, and extensions of basic rollback are proposed.  相似文献   
969.
The highest values in annual TSP distributions fall below the best-fit, log-normal straight line more than one would expect from ordinary sampling statistics but not dramatically so. The lowest values in annual TSP distributions overwhelmingly fall below the best-fit, log-normal straight line. The most highly improbable high values above the best-fit line in such distributions are very questionable and probably do not represent true air quality values. The most improbable cases of highest values falling below the best-fit, log-normal line are the result of data artifacts at the opposite end of the data distribution. They do not represent low probabilities and probably do represent true air quality values. The most improbable low values are all of highly doubtful validity.  相似文献   
970.
The primary objective of this study was to investigate the concentrations and spatial distribution of the total petroleum hydrocarbons (TPHs) in the intertidal zone surface sediment of Todos os Santos Bay, Brazil, to assess the distribution and degree of contamination by TPHs, measure the level of TPH degradation in the surface sediment, and identify the organic matter sources. The surface sediment used in this study was collected in 50 stations, and TPHs, isoprenoid alkanes (pristane and phytane), and unresolved complex mixture (UCM) were analyzed by gas chromatography with a flame ionization detector. The total concentrations ranged from 0.22 to 40,101 μg g?1 dry weight and showed a strong correlation with the total organic carbon (TOC) content. The highest TPH concentrations were observed in samples from the mangrove sediments of a river located near a petroleum refinery. Compared with other studies in the world, the TPH concentrations in the intertidal surface sediment of Todos os Santos Bay were below average in certain stations and above average in others. An analysis of the magnitude of UCM (0.11 to 17,323 μg g?1 dry weight) and the ratios nC17/Pr and nC18/Ph suggest that an advanced state of oil weathering, which indicates previous contamination. The molar C/N ratios varied between 5 and 43, which indicate organic matter with a mixed origin comprising marine and continental contributions.  相似文献   
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