خيارات البحث
النتائج 2701 - 2710 من 3,208
Heavy metal exposure from ingesting rice and its related potential hazardous health risks to humans النص الكامل
2015
Jallad, Karim N.
Different types of rice grains imported from 11 different countries and available on the Kuwaiti retail market were collected for heavy metal analysis. The surveyed rice samples were grouped according to their country of origin into four different regions namely Asia, Europe, Middle East, and North America. The samples were analyzed for total arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) using inductively coupled plasma mass spectrometry (ICP-MS). The data showed that the highest geometric means (GMs) of total As, Cd, Pb, and Hg contents were in rice samples imported from Europe, Asia, Europe, and the Middle East, respectively. The total As, Cd, Pb, and Hg concentrations in the analyzed rice samples were compared to the heavy metal content of 5800 rice samples from 25 different countries reported in the literature; furthermore, the heavy metal (total As, Cd, Pb, and Hg) concentrations determined in this study were implemented to calculate the daily dietary intake of toxic metals for the general population in the state of Kuwait, while the collected ones from the literature were implemented to calculate and then compare the daily dietary intake of toxic metals for the general population in 29 different countries around the world.
اظهر المزيد [+] اقل [-]Assessment of oxytetracycline and tetracycline antibiotics in manure samples in different cities of Khuzestan Province, Iran النص الكامل
2015
Alavi, Nadali | Babaei, Ali Akbar | Shirmardi, Mohammad | Naimabadi, Abolfazl | Goudarzi, Gholamreza
Tetracyclines (TCs), a class of antibiotics with a broad spectrum, are the most frequently used antibiotics in animal production. The major concern is that the widespread use of the antibiotics may lead to the emergence of new strains of bacteria that are resistant to these antibiotics. The objective of this study was to determine the residual levels of oxytetracycline and tetracycline in 80 animal manure samples that were collected from the livestock and poultry feedlots in Khuzestan Province. The residual levels of the antibiotics in the samples were extracted by using solid-phase extraction (SPE) method and subsequently were measured by liquid chromatography. Recoveries from the spiked poultry manure samples ranged from 65 to 113 % for tetracycline and 86 to 132 % for oxytetracycline. Relative standard deviations of the recoveries were less than 5.7 % within the same day. Method detection limit (MDL) measured for oxytetracycline and tetracycline in the manure were 0.011 and 0.01 mg/kg, respectively. Analysis of the collected 50 chickens and 30 cow manure samples showed that the highest concentration of tetracycline was related to Behbahan City (5.36 mg/kg) and the lowest concentration was detected for Ramhormoz (0.05 mg/kg). The highest and lowest concentrations of oxytetracycline were respectively observed for Behbahan (13.77 mg/kg) and Ramhormoz (0.047 mg/kg). Based on the results, in chicken manure, there was significant statistical difference between the residual TC concentrations among five cities (p ᵥₐₗᵤₑ < 0.05). However, no significant relationship was observed between oxytetracyclin (OTC) residual concentrations among five cities (p ᵥₐₗᵤₑ > 0.05).
اظهر المزيد [+] اقل [-]Using pre-screening methods for an effective and reliable site characterization at megasites النص الكامل
2015
Algreen, Mette | Kalisz, Mariusz | Stalder, Marcel | Martac, Eugeniu | Krupanek, Janusz | Trapp, Stefan | Bartke, Stephan
This paper illustrates the usefulness of pre-screening methods for an effective characterization of polluted sites. We applied a sequence of site characterization methods to a former Soviet military airbase with likely fuel and benzene, toluene, ethylbenzene, and xylene (BTEX) contamination in shallow groundwater and subsoil. The methods were (i) phytoscreening with tree cores; (ii) soil gas measurements for CH₄, O₂, and photoionization detector (PID); (iii) direct-push with membrane interface probe (MIP) and laser-induced fluorescence (LIF) sensors; (iv) direct-push sampling; and (v) sampling from soil and from groundwater monitoring wells. Phytoscreening and soil gas measurements are rapid and inexpensive pre-screening methods. Both indicated subsurface pollution and hot spots successfully. The direct-push sensors yielded 3D information about the extension and the volume of the subsurface plume. This study also expanded the applicability of tree coring to BTEX compounds and tested the use of high-resolution direct-push sensors for light hydrocarbons. Comparison of screening results to results from conventional soil and groundwater sampling yielded in most cases high rank correlation and confirmed the findings. The large-scale application of non- or low-invasive pre-screening can be of help in directing and focusing the subsequent, more expensive investigation methods. The rapid pre-screening methods also yielded useful information about potential remediation methods. Overall, we see several benefits of a stepwise screening and site characterization scheme, which we propose in conclusion.
اظهر المزيد [+] اقل [-]Phytodiversity on fly ash deposits: evaluation of naturally colonized species for sustainable phytorestoration النص الكامل
2015
Pandey, Vimal Chandra | Prakash, Prem | Bajpai, Omesh | Kumar, Akhilesh | Singh, Nandita
Proliferation of fly ash (FA) deposits and its toxicity have become a global concern, which contaminate the ecosystems of our Earth. In this regard, identification of potential plant species for FA deposits’ restoration is the main concern. Keeping this view in mind, the present study was conducted to identify potential plant species naturally growing on FA deposits for the restoration purposes. Six intensive surveys were made during 2010–2014 to collect naturally growing plant species during different seasons from two FA deposits in Unchahar of Raebareli district, Uttar Pradesh, India. The plant species having potential for FA deposits’ restoration were identified on the basis of their ecological importance, dominance at the study sites and socio-economic importance for rural livelihoods. Typha latifolia L., Cynodon dactylon (L.) Pers., Saccharum spontaneum L., Saccharum bengalense Retz. (syn. Saccharum munja), Prosopis juliflora (Sw.) DC., Ipomoea carnea Jacq. and Acacia nelotica L. are identified as potential plant species for FA deposits’ restoration. Furthermore, the characteristics of naturally colonized species can be used for the phytorestoration during a revegetation plan of new FA deposits for multiple benefits.
اظهر المزيد [+] اقل [-]Model development for naphthenic acids ozonation process النص الكامل
2015
Al jibouri, Ali Kamel H. | Wu, Jiangning
Naphthenic acids (NAs) are toxic constituents of oil sands process-affected water (OSPW) which is generated during the extraction of bitumen from oil sands. NAs consist mainly of carboxylic acids which are generally biorefractory. For the treatment of OSPW, ozonation is a very beneficial method. It can significantly reduce the concentration of NAs and it can also convert NAs from biorefractory to biodegradable. In this study, a factorial design (2⁴) was used for the ozonation of OSPW to study the influences of the operating parameters (ozone concentration, oxygen/ozone flow rate, pH, and mixing) on the removal of a model NAs in a semi-batch reactor. It was found that ozone concentration had the most significant effect on the NAs concentration compared to other parameters. An empirical model was developed to correlate the concentration of NAs with ozone concentration, oxygen/ozone flow rate, and pH. In addition, a theoretical analysis was conducted to gain the insight into the relationship between the removal of NAs and the operating parameters.
اظهر المزيد [+] اقل [-]The role of charged polymer coatings of nanoparticles on the speciation and fate of metal ions in the environment النص الكامل
2015
Domingos, Rute F. | Franco, Cristiana | Pinheiro, José P.
Determining the environmental risk of metals requires an in-depth understanding of the environmental matrices composition, which currently also includes the presence of manufactured metallic nanoparticles (NPs) usually, stabilized by a polymer surface coating. As a consequence, is necessary to take into account effects of the NP core, the polymer surface coating and their mutual interaction as well as with other environmental components. The release of metal ions from metallic NPs is a well-known outcome, however, the effect of the presence of the NP polymer coating in the NPs solubilization mechanism is not well understood. In this study the dynamic speciation of Cd and Pb in presence of a polyacrylic acid (PAA)-stabilized CdTe/CdS NP was quantified by scanned stripping chronopotentiometry (SSCP). It was found that although the NP solubility was 5.8× larger at pH 8.5 than at pH 6.0, the amount of free Cd ions was much smaller (2.4 % at pH 8.5 vs. 57 % at pH 6.0). The concentration of free Cd and Pb ions in solution was larger in presence of the PAA-shells than when in presence of the same amount of polymer but when this is at the surface of the NP. This effect is attributed to the metal ions interaction with the particle itself. The effect is notably larger for Pb ions and might results from the exchange of Cd by Pb ions at the particle surface since PbS is less soluble than CdS.
اظهر المزيد [+] اقل [-]Effect of exposure to O3, NO 2, and SO 2 on chronic obstructive pulmonary disease hospitalizations in Tabriz, Iran النص الكامل
2015
Ghozikali, Mohammad Ghanbari | Mosaferi, Mohammad | Safari, Gholam Hossein | Jaafari, Jalil
Air pollution in cities is a serious environmental problem especially in the developing countries. We examined the associations between gaseous pollutants and hospitalizations for chronic obstructive pulmonary diseases (COPD) among people living in Tabriz, a city in north western of Iran. We used the approach proposed by the World Health Organization (WHO) using the AirQ 2.2.3 software developed by the WHO European Center for Environment and Health, Bilthoven Division. To assess human exposure and health effect, data were used for ozone as a1h average; for nitrogen dioxide and sulfur dioxide as daily average concentrations. The association between air pollution and chronic obstructive pulmonary disease (COPD) was assessed using AirQ 2.2.3 model. The results of this study showed that 3 % (95 % CI 1.2–4.8 %) of HA COPD were attributed to O₃concentrations over 10 μg/m³. Also, 0.9 % (95 % CI 0.1–2.2 %) and 0.4 % (95 % CI 0–1.1 %) of HA COPD were attributed to NO₂and SO₂concentrations over 10 μg/m³, respectively. For every 10 μg/m³increase in O₃, NO₂, and SO₂concentrations, the risk of HA COPD increase to about 0.58, 0.38, and 0.44 %, respectively. We found significant positive associations between the levels of all air pollution and hospital admissions COPD. Otherwise, O₃, NO₂, and SO₂have a significant impact on COPD hospitalization.
اظهر المزيد [+] اقل [-]Selenium, nickel, and calcium levels in cancerous and non-cancerous prostate tissue samples and their relation with some parameters النص الكامل
2015
Çelen, İlker | Müezzinoğlu, Talha | Ataman, O Yavuz | Bakırdere, Sezgin | Korkmaz, Mehmet | Neşe, Nalan | Şenol, Feriye | Lekili, Murat
In the present study, tissue samples of patients with cancerous and non-cancerous prostate were analyzed for their Se, Ni, and Ca contents. Possible relationship between Se, Ni, and Ca concentrations and some parameters including preoperative prostate-specific antigen (PSA) levels, histopathological neurovascular invasion, extra-capsular extension, seminal vesicle invasion, positive surgical margins, PSA relapse after radical prostatectomy, and total Gleason scores were obtained. Inductively coupled plasma (ICP) optical emission spectrometry and ICP-mass spectrometry instruments were used for the determination of analytes interested. All the system parameters in digestion and measurement steps were optimized to obtain efficient digestion and sensitive measurements. There was no statistically meaningful difference observed in the concentration of selenium in cancerous and benign prostatic tissues (p = 0.347) while nickel levels in cancerous tissues were observed as significantly lower than benign tissues (p < 0.001). In addition, calcium concentration in cancerous tissue samples were found to be statistically lower than those in benign tissues (p < 0.001) with mean values of 657 and 1,431 mg/kg, respectively.
اظهر المزيد [+] اقل [-]The influence of sunlight and oxidative treatment on measured PAH concentrations in biochar النص الكامل
2015
Khalid, Fathima N. M. | Klarup, Doug
The concentration changes of 18 different polycyclic aromatic hydrocarbons (PAHs) in two different biochars were assessed after (1) chemical oxidative treatment with a solution of H₂O₂ and Na₂S₂O₈, (2) exposure to sunlight with intermittent wetting, and (3) exposure to sunlight with intermittent wetting after mixing in ZnO and Na₂S₂O₈. Chemical oxidative treatment of biochars derived from gasified wood biochar and a gasified wood/Arundo donax mixture led to decreases in six-ring PAHs, but overall significant increases in measured PAH concentration sums for both biochars (from 225 ± 7 to 312 ± 18 μg g⁻¹ for wood-derived and 165 ± 3 to 244 ± 7 μg g⁻¹ for mixture-derived). Sunlight exposure of the mixture-derived biochar led to increases in some three- and four-ring PAHs, but overall decreases in summed PAH concentrations (165 ± 3 to 60 ± 1 μg g⁻¹ with wetting only and 165 ± 3 to 41 ± 4 μg g⁻¹ when Na₂S₂O₈ and ZnO were included). The mass losses in the sunlight-exposed samples primarily were due to losses of low molar mass (two-ring) PAHs, though high molar mass (five- and six-ring) PAH concentrations also decreased. This result implies sun and rain exposure to biochar, prior to agricultural application, will help reduce potential PAH soil contamination from the biochar.
اظهر المزيد [+] اقل [-]Industrial sources of primary and secondary organic aerosols in two urban environments in Spain النص الكامل
2015
Escudero, M. | Viana, M. | Querol, X. | Alastuey, A. | Díez Hernández, P. | García Dos Santos, S. | Anzano, J.
In urban areas, primary and secondary organic aerosols are typically considered to originate from vehicular traffic emissions. However, industrial emissions within or in the vicinity of urban areas may also be significant contributors to carbonaceous aerosol concentrations. This hypothesis was tested and validated in two urban areas in Spain. The observed unusual dominance of organic carbon (OC) over elemental carbon (EC), the analysis of the variability of OC, EC and OC/EC and their correlation with transport patterns suggested the presence of OC sources associated with industrial activities. A methodology based on chemical speciation of particulate matter (PM) followed by the application of receptor modelling techniques allowed for the identification of the specific industrial sources of OC, which were linked to primary OC emissions from a grain drying plant (cereal) and to secondary OC formation from paper production activities (paper mills), as well as from urban sources and biogenic emissions. This work presents an integrated approach to identifying and characterizing of industrial sources of carbonaceous aerosols in urban areas, aiming to improve the scarce body of literature currently available on this topic.
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