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261.
Polybrominated diphenyl ethers (PBDEs), widely used as flame retardants in commercial products, have become ubiquitous environmental contaminants. Although adult human exposure to PBDEs is well documented, developmental exposure is less well characterized. The objectives of this study were to measure maternal and fetal exposure to nine PBDE congeners and to investigate potential associations with birth weight. PBDE congeners were quantified in maternal serum at 24-28 weeks of pregnancy, delivery, and umbilical cord serum (UCS) by gas chromatography-mass spectrometry (GC/MS/MS). Complete blood sample sets were obtained from 97 pregnant women (mean age 33.1 ± 0.5 years). PBDE-28, -47 and -99 were quantified in all samples tested and PBDE-47 was the most abundant congener measured in both maternal (mid-pregnancy and delivery samples geometric mean = 26.9 and 26.9, respectively) and UCS (GM = 56.0 ng g−1 lipid). The UCS concentration for all congeners with the exception of PBDE-153 was higher vs. maternal delivery samples (< 0.001). Only the UCS concentration of PBDE-17 and -99 were significantly associated (β = −49.860, = 0.032, and β = −3.645, = 0.05) with birth weight. However, after adjustment for potential confounders only the association between PBDE-99 and birth weight remained significant (β = −3.951 and = 0.016). We conclude that: the fetus is exposed to PBDEs from at least the second trimester of pregnancy onward; PBDE congeners are higher in UCS compared to maternal serum samples collected at delivery; and that developmental PBDE exposure is potentially associated with lower birth weight.  相似文献   
262.
Concentrations of POPs in Great skua eggs from Shetland are among the highest in North Atlantic seabirds, with up to 11,600 μg/kg (ww) DDE and up to 17,900 μg/kg ww ∑PCB. Concentrations of legacy POPs were significantly lower in 2008 than 1980. Decreases were greatest for least persistent compounds. Median ∑PBDEs increased from 99 μg/kg ww in 1980 to 173 μg/kg ww in 2008. There were changes in Great skua breeding season diet, with more adult Herring and Mackerel and less Sandeel. These changes increase exposure to POPs, since Herring and Mackerel accumulate more POPs than Sandeels. In both years, eggs with higher δ15N had higher POP concentrations. In 1980, birds feeding more on demersal discard fish from trawl fisheries and less on Sandeels, had higher POP levels in eggs. In 2008, individuals feeding more on Herring and Mackerel, and less on discards, had higher POP levels in eggs.  相似文献   
263.
Two herbicides, 2,4-D and triclopyr esters (application ratio 1.6:1 acid equivalents) were applied as a tank mix by a crew of 8 backpack sprayer applicators, a mixer/loader, and a field supervisor. The crew was employed in a conifer release program in northern California during the summer of 2002. Biomonitoring (urine, 24 h) utilized 2,4-D and triclopyr (a.e.) as rapidly excreted exposure biomarkers. The absorbed dosages of 2,4-D and triclopyr were calculated based upon cotton whole body suits and biomonitoring. Dosages based upon accumulation of the herbicides on body suits averaged 42.6 μg (a.e.) 2,4-D/kg-d and 8.0 μg (a.e.) triclopyr/kg-d. Six consecutive days of concurrent urine collections showed that backpack applicators excreted an average of 11.0 μg (a.e.) 2,4-D/kg-d and 18.9 μg (a.e.) triclopyr/kg-d. Estimates based upon curve fitting were 17.1 and 29.3 μg (a.e.)/kg-d, respectively. Results suggest that passive dosimetry for 2,4-D consistently overestimated the dosage measured using biomonitoring by a factor of 2-3 fold, while for triclopyr, passive dosimetry underestimated the absorbed dose based on biomonitoring by a factor of 2-4 fold.  相似文献   
264.
Contamination problems are often characterized by complex mixtures of chemicals. There are two conceptual models usually used to evaluate patterns of mixture toxicity: Concentration Addition (CA) and Independent Action (IA). Deviations from these models as synergism, antagonism and dose dependency also occur. In the present study, single and mixture toxicity of atrazine, dimethoate, lindane, zinc and cadmium were tested in Porcellionides pruinosus and Enchytraeus albidus, using avoidance as test parameter. For both species patterns of antagonism were found when exposed to dimethoate and atrazine, synergism for lindane and dimethoate exposures (with the exception of lower doses in the isopod case study) and concentration addition for cadmium and zinc occurred, while the exposure to cadmium and dimethoate showed dissimilar patterns.This study highlights the importance of dose dependencies when testing chemical mixtures and that avoidance tests can also be used to asses the effects of mixture toxicity.  相似文献   
265.
Enantiomeric analysis can be used as a complementary tool for source apportionment of chiral compounds, particularly for α-HCH. In this study we used archived samples from studies related to the distribution of POPs in air–water and air–soil–grass systems. Such approach is based on the behaviour of chiral compounds released into the atmosphere from a primary source, when they are expected to show racemic or close to racemic composition. Contrarily, when chiral compounds have been reemitted from secondary sources (e.g. water or soil), their enantiomeric signatures are frequently non-racemic and are similar to the signature of the secondary source. To show such evidence, extracts from passive air samples deployed throughout Europe were analyzed for the enantiomers of α-HCH. The proximity to a large water body showed a high impact on the enantiomeric signatures: Baltic air had enantiomeric fractions (EFs) < 0.500, while Mediterranean air had predominantly EFs > 0.500. Similarly, Atlantic air showed a latitude influence: above 50°N most EFs < 0.500, whereas at latitudes below 50°N, EFs were > 0.500. A similar trend was also observed for EFs of α-HCH measured in air samples from a latitudinal transect during an Atlantic cruise. This transect shows that samples from higher latitudes (above 40°N) have EF < 0.500, whereas in the more southern samples (African coast and Southern Atlantic), there is no clear trend for EFs. Inland air samples showed a large range in EF values, with racemic signatures for samples with the highest α-HCH concentrations and an increasing spread in the EFs for lower α-HCH concentrations. As expected, the EF values of α-HCH in air, soils and grass were also impacted by latitude. Correlations between EFs and geographic characteristics of the sampling locations, as well as α-HCH concentrations, α-/γ-isomer ratios, or temperature suggest that enantioselective analysis can give additional information on the distribution and sources of α-HCH in the environment.  相似文献   
266.
267.
It has been widely acknowledged that people’s beliefs and perceptions influence implementation of climate change adaptation. Regarding perception barriers, some authors keep highlighting the confused definition of adaptation and its various interpretations. Our research contributes to this area by exploring how adaptation to climate change is perceived through 83 semi-structured interviews with stakeholders (public and municipal organizations, ENGO, private sector) from Montreal and Paris. Our results demonstrate a mirror opposition in the perception of adaptation to climate change. Indeed, while several respondents interpreted adaptation as a resignation, many interviewees perceived adaptation as an opportunity. The analysis showed that adaptation referring to resignation includes the ideas of a non-action and detrimental to mitigation; an excuse for not changing; anxiety about climate change; fatalism; and human failure. Adaptation perceived as an opportunity is divided into a source of creativity; toward sustainable development; led by the emergency; and awareness and making society of its responsibilities. Our findings confirm that terminological ambiguity of the term “adaptation” has to be considered in the decision-making process, which can be influenced by the perception of stakeholders.  相似文献   
268.

Purpose  

The Llobregat River, which is characterized by important fluctuations of the flow rates, receives treated waters from WWTPs. During the years 2007 and 2008, the Llobregat River basin suffered from a severe drought which affected the supply of drinking water facilities (DWF) that rely on the exploitation of the river water. The Catalan Water Agency implemented a water reuse experiment with the objective of maintaining the river flow rate at sufficiently high level so as to ensure the supply of raw water to Barcelona’s major DWF.  相似文献   
269.

Introduction  

Mediterranean rivers are characterized by a high flow variability, which is strongly influenced by the seasonal rainfall. When water scarcity periods occur, water flow, and dilution capacity of the river is reduced, increasing the potential environmental risk of pollutants. On the other hand, floods contribute to remobilization of pollutants from sediments. Contamination levels in Mediterranean rivers are frequently higher than in other European river basins, including pollution by pharmaceutical residues. Little attention has been paid to the transport behavior of emerging contaminants in surface waters once they are discharged from WWTP into a river. In this context, this work aimed to relate presence and fate of emerging contaminants with hydrological conditions of a typical Mediterranean River (Llobregat, NE Spain).  相似文献   
270.

Purpose

The aim of this paper was to develop a new recreational water quality index (RWQI) as a tool to ensure the health of swimmers and to take practical decisions.

Methods

RWQI was elaborated with epidemiological data, and we carried out an exhaustive study of the different guidelines for recreational waters proposed by different organisations around the world. Different parameters were chosen, considering, as a priority, the swimmer??s contact and the possibility of ingestion of water during the recreational activity. Furthermore, rating curves were established for pH, chemical oxygen demand, nitrate, phosphate, detergents, enterococci, total coliforms, faecal coliforms and Escherichia coli.

Results and conclusions

The index was applied to the data set on water quality of the Potrero de los Funes River (San Luis, Argentina), generated during 2 years (2009?C2010). Following the RWQI values classification, most of the Potrero de los Funes water samples fell in the good quality range during the study period.  相似文献   
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