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31.
Behnam Haidari Alireza Riyahi Bakhtiari Vhid Yavari Ali Kazemi Golshan Shirneshan 《洁净——土壤、空气、水》2013,41(2):166-173
Vanadium and nickel are two important indicators of oil pollution. Lengthy exposure to these elements causes serious harmful effects in human health, different harsh allergies being examples. The accumulation of two heavy metals (Ni and V) in sediment and the soft and hard tissues of Saccostrea cucullata were analyzed at three sampling sites along the coast of Lengeh Port, Persian Gulf. Results indicated at all the sampling sites; the Ni levels in soft tissues (STs) were higher than in the shells (SHs) and sediments, whereas the V levels were higher in the sediments. In addition, meaningful relationship (r = 0.65; p < 0.05) was observed across Ni levels in ST of S. cucullata and sediment, while for V concentrations a strong relationship (r = 0.83; p < 0.01) was found in SH of S. cucullata and sediment. This indicates that ST and SH of oyster can be considered as a biomonitoring agent for Ni and V levels, in coastal waters, respectively. The exposure of the consumer is compared directly to minimal risk level and provisional maximum tolerable daily intake. Result indicated that levels of Ni and V were within the safety limits for human consumption. 相似文献
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Daniel Puig Oswaldo Morales-Nápoles Fatemeh Bakhtiari Gissela Landa 《Climate Policy》2018,18(6):742-751
Governmental climate change mitigation targets are typically developed with the aid of forecasts of greenhouse-gas (GHG) emissions. The robustness and credibility of such forecasts depends, among other issues, on the extent to which forecasting approaches can reflect prevailing uncertainties. We apply a transparent and replicable method to quantify the uncertainty associated with projections of gross domestic product growth rates for Mexico, a key driver of GHG emissions in the country. We use those projections to produce probabilistic forecasts of GHG emissions for Mexico. We contrast our probabilistic forecasts with Mexico’s governmental deterministic forecasts. We show that, because they fail to reflect such key uncertainty, deterministic forecasts are ill-suited for use in target-setting processes. We argue that (i) guidelines should be agreed upon, to ensure that governmental forecasts meet certain minimum transparency and quality standards, and (ii) governments should be held accountable for the appropriateness of the forecasting approach applied to prepare governmental forecasts, especially when those forecasts are used to derive climate change mitigation targets.
POLICY INSIGHTS
No minimum transparency and quality standards exist to guide the development of GHG emission scenario forecasts, not even when these forecasts are used to set national climate change mitigation targets.
No accountability mechanisms appear to be in place at the national level to ensure that national governments rely on scientifically sound processes to develop GHG emission scenarios.
Using probabilistic forecasts to underpin emission reduction targets represents a scientifically sound option for reflecting in the target the uncertainty to which those forecasts are subject, thus increasing the validity of the target.
Setting up minimum transparency and quality standards, and holding governments accountable for their choice of forecasting methods could lead to more robust emission reduction targets nationally and, by extension, internationally.
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Phenolic endocrine disrupting chemicals (EDCs) in Anzali Wetland, Iran: elevated concentrations of 4-nonylphenol, octhylphenol and bisphenol A 总被引：2，自引：0，他引：2
Mortazavi S Bakhtiari AR Sari AE Bahramifar N Rahbarizade F 《Marine pollution bulletin》2012,64(5):1067-1073
We have studied the distribution and value of phenolic endocrine disrupting chemicals (EDCs) in surface sediment samples taken from Anzali Wetland, Iran. These samples were collected from 22 stations during the time span of June-May 2010. In each of the sampling stations, we detected 4-nonylphenol (4-NP), octylphenol (OP), and bisphenol A (BPA) with maximal concentrations of 29, 4.3, and 7 μg g(-1) dry weight (dw), respectively. High levels of alkylphenols (APs) and BPA were also found near urban areas. Furthermore there were no significant differences between those stations in terms of the detected levels. One of the important factors in controlling the fate of these compounds in the aquatic environment appeared to be Total Organic Carbon (TOC). Hierarchical cluster analysis showed differences in the biomarker characteristics of EDCs and TOC between the stations. Our findings indicate that EDCs are ubiquitous in sediments from northeast Wetlands of Iran, contaminating the aquatic habitats in this area. 相似文献
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To assess the risk of release and percentage of heavy metals in river sediment, nine stations were set up to sample surface sediments from three important rivers situated southwest of the Caspian Sea (the Shafaroud, Karaganroud, and Choubar Rivers). Chemical analyses were conducted on sediment with particle sizes of >38, 63–38, 63–125, 125–250, 250–500 and 500–1000 µm using metal fractionation to determine the degree of risk release and the heavy metal pollution. Common risk indices were used including the cumulative indices of pollution intensity assessment and risk release standards (the modified pollution degree and ecological risk). Generally, when sediment sizes are decreased, the concentration of heavy metals is both larger and greater than the mean concentration of global sediments and earth crust. However, in this research, the concentration of all the metals did not necessarily increase with a decrease in the size of particles. In fact, concentration of cobalt, vanadium, cadmium, and chromium was greater in sediment particle sizes over 63 μm. The results of chemical fractionation analyses indicated that the release risk of metals has two initial phases for: (1) exchangeable bond (F1) and (2) carbonated bond (F2). When compared with other metals, nickel had the greatest tendency to bond within the loose exchangeable phase (F1) across all the stations. Furthermore, with changes in the size of particles, the percentage of heavy metal changes across different bond phases, but will be the greatest in the loose exchangeable phase (F1). This was observed with cobalt, nickel, and chromium at particle sizes larger than 63 μm. The results of ecological risk and modified pollution degree indices indicated that the highest level of pollution was related to sediments with sizes between 63 and 250 μm. Eventually, in order to assess the risk extent of metals present in sediment, a cumulative index referred to as the modified risk assessment code was utilized. It suggested that the greatest risk of toxicity in some stations has been related to particles larger than 63 μm. 相似文献
35.
Fasihnikoutalab Mohammad Hamed Pourakbar Shahram Ball Richard J. Unluer Cise Cristelo Nuno 《Acta Geotechnica》2020,15(7):1981-1991
Acta Geotechnica - Ground granulated blast-furnace slag (GGBS), activated with olivine (Mg2SiO4) and sodium hydroxide (NaOH), was used to stabilise a clayey soil. Mechanical and microstructural... 相似文献
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Khosrojerdi Tooraj Moosavirad Seyed Hamed Ariafar Shahram Ghaeini-Hessaroeyeh Mahnaz 《Natural Resources Research》2019,28(3):1107-1124
Natural Resources Research - Efficient water allocation is one of the most prominent issues in water resources management. In this research, a two-stage interval-parameter stochastic fuzzy... 相似文献
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Alireza Riyahi Bakhtiari Mohamad Pauzi Zakaria Mohammad Ismail Yaziz Mohamad Nordin Hj Lajis Xinhui Bi Mohamad Che Abd Rahim 《Applied Geochemistry》2009,24(9):1777-1787
Four anoxic sediment cores were collected from Chini Lake, Malaysia in order to investigate the variability of polycyclic aromatic hydrocarbon (PAH) and perylene concentrations. The study also determined significant differences of perylene concentrations in different sediment layers. Total PAH concentrations ranged from 248 to 8098 ng g−1 in the samples. Diagnostic PAH ratios such as methylphenanthrenes/phenanthrene (MP/P), phenanthrene/anthracene (P/A) and fluoranthene/(fluoranthene + pyrene) (Fl/(Fl + Py) revealed a dominance of pyrogenic influences and partial petrogenic inputs to the top sediment layers. Perylene concentrations were high in the top layers (<12 cm) and increased with increasing depth. There is a significant positive correlation (r = 0.705, p = 0.01) between perylene concentrations and TOC. Analysis of variance (ANOVA) and LSD revealed significant differences (p < 0.05) in TOC-normalized perylene concentrations between the upper (<12 cm) and bottom layers (>12 cm). The average perylene concentrations accounted for 26–50% (0–12 cm) and 50–77% (12–36 cm) of pentacyclic-aromatic hydrocarbon isomers (PAI) present whereas it made up 10–34% (0–12 cm) and 46–66% (12–36 cm) of the total PAH. The average pyrene concentrations decreased with increasing depth and accounted for 62% (0–3 cm), 20–23% (3–12 cm) and 3–1.4% (12–36 cm) of perylene present. The results of hierarchical cluster analysis based on these ratios suggested different input sources for the top and bottom layers. It is concluded that the activity of termites on woody plants produced perylene which is supplied to the lake by run-off from the heavy and frequent rains in this Asian tropical climate. In addition, there was also in situ formation of perylene in the bottom layers due to diagenetic processes. 相似文献
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Shahram?Shahmohammadi-KalalaghEmail author Hossein?Babazadeh Amirhossein?Nazemi 《Arabian Journal of Geosciences》2015,8(1):397-402
The most appropriate method in designing the adsorption systems and assessing the performance of the adsorption systems is to have an idea on adsorption isotherms. Comparison analysis of linear least square method and nonlinear method for estimating the isotherm parameters was made using the experimental equilibrium data of Zn(II) and Cu(II) onto kaolinite. Equilibrium data were fitted to Freundlich, Langmuir, and Redlich–Peterson isotherm equations. In order to confirm the best-fit isotherms for the adsorption system, the data set using the chi-square (χ 2), combined with the values of the determined coefficient (r 2) was analyzed. Nonlinear method was found to be a more appropriate method for estimating the isotherm parameters. The best fitting isotherm was the Langmuir and Redlich–Peterson isotherm. The Redlich–Peterson is a special case of Langmuir when the Redlich–Peterson isotherm constant g was unity. The sorption capacity of kaolinite to uptake metal ions in the increasing order was given by Cu (4.2721 mg/g)?<?Zn (4.6710 mg/g). 相似文献