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Результаты 421-430 из 3,207
Interspecies variation in the risks of metals to bats Полный текст
2015
Hernout, Béatrice V. | Pietravalle, Stéphane | Arnold, Kathryn E. | McClean, Colin J. | Aegerter, James | Boxall, Alistair B.A.
A modeling framework was used to assess the risk of four metals to UK bat species. Eight species of bats were predicted to be “at risk” from one or more of the metals in over 5% of their ranges. Species differed significantly in their predicted risk. Contamination by Pb was found to pose the greatest risk, followed by Cu, Cd and Zn. A sensitivity analysis identified the proportion of invertebrates ingested as most important in determining the risk. We then compared the model predictions with a large dataset of metals concentrations in the tissues (liver, kidney) of Pipistrellus sp. from across England and Wales. Bats found in areas predicted to be the most “at risk” contained higher metal concentrations in their tissues than those found in areas predicted “not at risk” by the model. Our spatially explicit modeling framework provides a useful tool for further environmental risk assessment studies for wildlife species.
Показать больше [+] Меньше [-]Ambient air pollution, temperature and out-of-hospital coronary deaths in Shanghai, China Полный текст
2015
Dai, Jinping | Chen, Renjie | Meng, Xia | Yang, Changyuan | Zhao, Zhuohui | Kan, Haidong
Few studies have evaluated the effects of ambient air pollution and temperature in triggering out-of-hospital coronary deaths (OHCDs) in China. We evaluated the associations of air pollution and temperature with daily OHCDs in Shanghai, China from 2006 to 2011. We applied an over-dispersed generalized additive model and a distributed lag nonlinear model to analyze the effects of air pollution and temperature, respectively. A 10 μg/m3 increase in the present-day PM10, PM2.5, SO2, NO2 and CO were associated with increases in OHCD mortality of 0.49%, 0.68%, 0.88%, 1.60% and 0.08%, respectively. A 1 °C decrease below the minimum-mortality temperature corresponded to a 3.81% increase in OHCD mortality on lags days 0–21, and a 1 °C increase above minimum-mortality temperature corresponded to a 4.61% increase over lag days 0–3. No effects were found for in-hospital coronary deaths. This analysis suggests that air pollution, low temperature and high temperature may increase the risk of OHCDs.
Показать больше [+] Меньше [-]Fullerenes(nC60) affect the growth and development of the sediment-dwelling invertebrate Chironomus riparius larvae Полный текст
2015
Waissi-Leinonen, Greta C. | Nybom, Inna | Pakarinen, Kukka | Akkanen, Jarkko | Leppänen, Matti T. | Kukkonen, Jussi V.K.
The possible toxicity of nanoparticles (NPs) to aquatic organisms needs to be investigated for chronic effects at low concentrations. Chronic effects of carbon NPs, fullerenesC60, on the midges of Chironomus riparius at different life stages on larvae and adult midges were investigated. Sediment associated fullerenesC60 were studied by 10-day growth and 42-day emergence tests with artificial sediment at nominal concentration ranges 0.0004–80 mg/kg dry weight. The body length decreased in the lower tested concentrations (0.0025–20 mg/kg), but the effect vanished with higher concentrations. Delayed emergence rate observed at 0.5 mg/kg. The observed effects correlated with analyzed sediment particle sizes indicating that small agglomerates of fullerene have more significant effects on C. riparius than larger agglomerates observed with higher C60 doses. The results reveal that fullerene may pose risks to benthic organisms, emerging as changes in the ecotoxic parameters studied here which inflects by the survival of the population.
Показать больше [+] Меньше [-]Slash-and-char: An ancient agricultural technique holds new promise for management of soils contaminated by Cd, Pb and Zn Полный текст
2015
Niu, Li-qin | Jia, Pu | Li, Shao-peng | Kuang, Jia-liang | He, Xiao-xin | Zhou, Wen-hua | Liao, Bin | Shu, Wen-sheng | Li, Jin-tian
Heavy metal contamination of agricultural soils is of worldwide concern. Unfortunately, there are currently no efficient and sustainable approaches for addressing this concern. In this study, we conducted a field experiment in which an agricultural soil highly contaminated by cadmium (Cd), lead (Pb) and zinc (Zn) was treated on-site by an ancient agricultural technique, ‘slash-and-char’, that was able to convert the biomass feedstock (rice straw) into biochar in only one day. We found evidence that in comparison to the untreated soil, the treated soil was associated with decreased bioavailability of the heavy metals and increased vegetable yields. Most importantly, the treatment was also coupled with dramatic reductions in concentrations of the heavy metals in vegetables, which made it possible to produce safe crops in this highly contaminated soil. Collectively, our results support the idea that slash-and-char offers new promise for management of soils contaminated by Cd, Pb and Zn.
Показать больше [+] Меньше [-]Levels and source apportionment of children's lead exposure: Could urinary lead be used to identify the levels and sources of children's lead pollution? Полный текст
2015
Cao, Suzhen | Duan, Xiaoli | Zhao, Xiuge | Wang, Beibei | Ma, Jin | Fan, Delong | Sun, Chengye | He, Bin | Wei, Fusheng | Jiang, Guibin
As a highly toxic heavy metal, the pollution and exposure risks of lead are of widespread concern for human health. However, the collection of blood samples for use as an indicator of lead pollution is not always feasible in most cohort or longitudinal studies, especially those involving children health. To evaluate the potential use of urinary lead as an indicator of exposure levels and source apportionment, accompanying with environmental media samples, lead concentrations and isotopic measurements (expressed as 207Pb/206Pb, 208Pb/206Pb and 204Pb/206Pb) were investigated and compared between blood and urine from children living in the vicinities of a typical coking plant and lead-acid battery factory. The results showed urinary lead might not be a preferable proxy for estimating blood lead levels. Fortunately, urinary lead isotopic measurements could be used as an alternative for identifying the sources of children's lead exposure, which coincided well with the blood lead isotope ratio analysis.
Показать больше [+] Меньше [-]Temporal-spatial distributions and ecological risks of perfluoroalkyl acids (PFAAs) in the surface water from the fifth-largest freshwater lake in China (Lake Chaohu) Полный текст
2015
Liu, Wen-Xiu | He, Wei | Qin, Ning | Kong, Xiang-Zhen | He, Qi-Shuang | Yang, Bin | Yang, Chen | Jorgensen, Sven Erik | Xu, Fu-Liu
To investigate the residues, compositions, distributions and potential ecological risks of perfluoroalkyl acids (PFAAs), water samples were collected seasonally between August 2011 and November 2012 from 20 sites in Lake Chaohu and its tributary rivers. The mean concentration of total PFAAs (TPFAAs) was 14.46 ± 6.84 ng/L. PFOA was the predominant contaminant (8.62 ± 4.40 ng/L), followed by PFBA (2.04 ± 1.16 ng/L) and PFHxA (1.23 ± 1.50 ng/L). The TPFAAs concentrations peaked in August 2012 in each area, except for the western river. The opposite spatial trends were found for PFOA and PFOS in both the lake and river areas. Except for PFOS and PFUdA, the levels of TPFAAs and PFAAs were significantly related to the composition of fluorescent dissolved organic matter (FDOM) but not related to total DOM expressed by dissolved organic carbon (DOC). The risk of PFOS determined by a species sensitivity distribution model was notably above that of PFOA.
Показать больше [+] Меньше [-]Fate and transport of free and conjugated estrogens during soil passage Полный текст
2015
Goeppert, Nadine | Dror, Ishai | Berkowitz, Brian
Endocrine disrupting chemicals, such as the free estrogens 17β-estradiol (E2), estrone (E1) and the conjugated estrogen estrone-sulfate (E1-3S) are found at low concentration levels in the environment. This is somehow contradictory to the strong sorption and high degradation potentials found in laboratory experiments. In particular, the fate and transport behavior of conjugated estrogens is poorly understood, and the importance of enzymes triggering the transformation pathways has received little attention. To address these deficiencies, the present research uses packed laboratory soil columns with pulse injections of free estrogens, either E2 or E1, or E1-3S, to provide sound evidence of the transformation pathways. It is further shown that (i) transport of free estrogens is subject to strong retardation and degradation, (ii) the transport of conjugated estrogens is less retarded and only to a minor degree affected by degradation, and (iii) arylsulfotransferase is the enzyme triggering the transformation reaction.
Показать больше [+] Меньше [-]Temporal and spatial trends in sediment contaminants associated with toxicity in California watersheds Полный текст
2015
Siegler, Katie | Phillips, Bryn M. | Anderson, Brian S. | Voorhees, Jennifer P. | Tjeerdema, Ron S.
California's Stream Pollution Trends program (SPoT) assesses long-term water quality trends, using 100 base-of-the-watershed sampling sites. Annual statewide sediment surveys from 2008 to 2012 identified consistent levels of statewide toxicity (19%), using the freshwater amphipod Hyalella azteca. Significant contaminant trends included a decrease in PCBs, stable concentrations of metals and PAHs, and a statewide increase in detections and concentrations of pyrethroid pesticides. The pyrethroid pesticide bifenthrin was detected in 69% of samples (n = 410). Detection of toxicity increased in a subset of samples tested at a more environmentally relevant test temperature (15 °C), and the magnitude of toxicity was much greater, indicating pyrethroid pesticides as a probable cause. Pyrethroid toxicity thresholds (LC50) were exceeded in 83% of samples with high toxicity. Principal components analysis related pyrethroids, metals and total organic carbon to urban land use.
Показать больше [+] Меньше [-]Uptake of antimonite and antimonate by arsenic hyperaccumulator Pteris vittata: Effects of chemical analogs and transporter inhibitor Полный текст
2015
Tisarum, Rujira | Chen, Yanshan | Dong, Xiaoling | Lessl, Jason T. | Ma, Lena Q.
Antimonite (SbIII) is transported into plants via aquaglyceroporin channels but it is unknown in As-hyperaccumulator Ptreis vittata (PV). We tested the effects of SbIII analogs (arsenite-AsIII, glycerol, silicic acid-Si, and, glucose), antimonate (SbV) analog (phosphate-P), and aquaglyceroporin transporter inhibitor (silver, Ag) on the uptake of SbIII or SbV by PV gametophytes. PV gametophytes were grown in 20% Hoagland solution containing 65 μM SbIII or SbV and increasing concentrations of analogs at 65–6500 μM for 2 h or 4 h under sterile condition. After exposing to 65 μM Sb for 2 h, PV accumulated 767 mg/kg Sb in SbIII treatment and 419 mg/kg in SbV treatment. SbIII uptake by PV gametophytes was not impacted by glycerol or AsIII nor aquaglyceroporin inhibitor Ag during 2 h exposure. While Si increased SbIII uptake and glucose decreased SbIII uptake by PV gametophytes, the impact disappeared during 4 h exposure. Under P-sufficient condition, P increased SbIII uptake and decreased SbV uptake during 2 h exposure, but the effect again disappeared after 4 h. After being P-starved for 2 weeks, P decreased SbIII with no effect on SbV uptake during 2 h exposure. Our results indicated that: 1) PV gametophytes could serve as an efficient model to study Sb uptake, and 2) unique SbIII uptake by PV may be related to its trait of As hyperaccumulation.
Показать больше [+] Меньше [-]Microplastic and macroplastic ingestion by a deep diving, oceanic cetacean: The True's beaked whale Mesoplodon mirus Полный текст
2015
Lusher, Amy L. | Hernandez-Milian, Gema | O'Brien, Joanne | Berrow, Simon | O'Connor, Ian | Officer, Rick
When mammals strand, they present a unique opportunity to obtain insights into their ecology. In May 2013, three True's beaked whales (two adult females and a female calf) stranded on the north and west coasts of Ireland and the contents of their stomachs and intestines were analysed for anthropogenic debris. A method for identifying microplastics ingested by larger marine organisms was developed. Microplastics were identified throughout the digestive tract of the single whale that was examined for the presence of microplastics. The two adult females had macroplastic items in their stomachs. Food remains recovered from the adult whales consisted of mesopelagic fish (Benthosema glaciale, Nansenia spp., Chauliodius sloani) and cephalopods, although trophic transfer has been discussed, it was not possible to ascertain whether prey were the source of microplastics. This is the first study to directly identify microplastics <5 mm in a cetacean species.
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