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261.
Mudassar Khan Ashiq Mohammad Karam Ahad Athanasios Katsoyiannis Salman Akbar Malik Muhammad Abdullaha Azhar Rashid Mauro Fasola Alamdar Hussain Habib Bokhari Syed Ali Musstjab Akber Shah Eqani 《Environmental geochemistry and health》2014,36(3):375-384
We investigated selected chlorinated pollutants (β-HCH, γ-HCH, DDDs, DDEs, o,p′-DDT, p,p′-DDT, heptachlor, aldrin, dieldrin, and endrin) in the Lahore and the Sialkot districts of Pakistan, using eggs of cattle egret (Bubulcus ibis) collected during May and June 2007. The pollutant with highest level and frequency was ΣDDT, followed by β-HCH, γ-HCH, heptachlor, aldrin, dieldrin, and endrin in descending order. The concentration(s) were significantly higher in Sialkot heronry for all the pollutants (except p,p′-DDT) than in Lahore. The values for DDTs, β-HCH, γ-HCH, and heptachlor were significantly higher (p < 0.05) in the egg(s) than in sediment(s) and in the chicks’ diet, due to biomagnification. Among DDTs analogues, p,p′-DDD was the major contaminant with >60 % of total DDT burden, reflecting the widespread aged as well as recent use of DDT as well as anaerobic degradation (DDD/DDE > 1 in many cases) in the nearby paddy soils. In few samples, p,p′-DDT/(DDD + DDE) > 0.5 suggested the recent emission patterns from surrounding contaminated areas of demolished DDT units and obsolete pesticide stores. The higher levels of HCHs (i.e., β-HCH) in the samples collected from Sialkot indicate exposure from long-term agricultural use. Overall, concentrations of all studied POPs were less than the threshold levels known to affect reproduction. Nevertheless, total DDTs and/or HCHs burdens in some eggs contained concentrations of greater than what would educe adverse effects on birds. This is among few studies on OCPs exposure to avian species, which provide the evidence of Pakistan’s contribution toward the Global POPs emission. 相似文献
262.
Adult respiratory distress syndrome (ARDS) is a clinical syndrome which occurs due to various direct or indirect noxious agents and pyhsical mechanisms. One of the etiological factors is ingested chemicals (e.g. paraquat, ethylene glycol). The organophosphorous (OP) insecticides are the most toxic and frequently encountered chemicals that produce poisoning in humans. Studies were undertaken to investigate whether OP insecticides may produce ARDS. Fifteen autopsy cases due to suicidal OP insecticide poisoning were investigated. Toxicological analyses were performed with a gas chromatography-nitrogen phosphorous detector (GC-NPD). Methamidophos, dimefox and dichlorvos were the detected OP. Lungs were examined macroscopically. Two cases showed features compatible with ARDS in which the only cause of death was OP poisoning. Due to the severity of ARDS it is important to assess insecticidal exposure in an attempt to enhance survival patterns following OP poisoning in patients in order to initiate therapy. 相似文献
263.
Ali Almasi Mehdi Omidi Mehdi Khodadadian Razieh Khamutian Mohammad Bagher Gholivand 《毒物与环境化学》2013,95(4):660-671
The biosorption potential of processed walnut shell for Pb(II) and Cd(II) ions from aqueous solutions was explored. The effects of pH, contact time, initial ion concentration, and amount of dried adsorbent were studied in batch experiments. The maximum adsorption was achieved within the pH range 4.0–6.0. The equilibrium data were well fitted by the Langmuir isotherm model. The maximum monolayer adsorption capacities were found to be 32?g?kg?1 and 11.6?g?kg?1 for Pb(II) and Cd(II) ions, respectively. Kinetic data were best described by the pseudo-second-order model. The structural features of the adsorbent were characterized by Fourier transform infrared spectroscopy, which confirmed the involvement of hydroxyl (–OH), carboxyl (–COO–), and carbonyl (C=O) groups in metal sorption. This readily available adsorbent is efficient in the uptake of Pb(II) and Cd(II) ions from an aqueous solution and could be used for the treatment of wastewater streams bearing these metal ions. 相似文献
264.
Mojtaba Davoudi Simin Naseri Amir Hossein Mahvi Mehdi Farzadkia Ali Esrafili 《毒物与环境化学》2013,95(9):1310-1332
The post treatment of simulated tannery wastewater was evaluated in an electrochemical oxidation process under galvanostatic conditions. A continuous flow reactor divided by a cellulosic membrane consisted of Ti/SnO2–Sb anodes and iron cathodes was used. Central composite design and response surface methodology (RSM) were applied to investigate the effects of six operational parameters, namely initial concentration of total phenols (TPh), total chromium (TCr), total ammonia nitrogen (TAN), flow rate (Q), current intensity (I), and electrode surface area (A). Effectiveness of the innovative cellulosic membrane was proven by considerable pH variations in the anolyte and catholyte chambers. A faster removal rate was observed for TPh and TAN, followed by TCr. The treatment level was very sensitive to Q and I in the studied ranges. RSM showed the removal efficiencies of 78.14%, 63.42%, and 86.09% for TPh, TCr, and TAN, respectively, are achieved under optimal conditions with consumption of only 9.03 kWh m?3 electrical energy. Chlorinated compounds such as chloroform, 2,4-dichlorophenol, and chlorobenzene were detected as the degradation intermediates. According to the obtained results, electrolysis in the divided cell with cellulosic membrane is a practical, cost-effective method for advanced treatment of tannery effluents. 相似文献
265.
AbstractA rapid and selective technique for extraction, preconcentration and determination of trace amounts of cobalt in water and pharmaceutical samples by air-assisted liquid–liquid microextraction combined with flame atomic absorption spectrometry is proposed. 1-Nitroso-2-naphthol is used as a complexing agent and 1-octanol as an extraction solvent. Parameters relevant for analytical effectivity, i.e. pH of sample solution, concentration of complexing agent, volume of extraction solvent, and number of extraction cycles are optimized using a Box–Behnken design. At optimum conditions, a dynamic linear range of 5–600?µg L?1 is obtained, with a limit of detection of 1.2?µg L?1. The method is used for determination of Co(II) in environmental water and pharmaceutical samples. 相似文献
266.
Sabzar Ahmad Dar Abdul Rehman Yousuf Masood-ul-Hassan Balkhi Md Niamat Ali 《毒物与环境化学》2013,95(6):906-916
Oxidative stress and antioxidant responses of crucian carp, upon chronic exposure to endosulfan, were evaluated in vivo. The lethal concentration (LC50–96?h) was 70 μg L?1; on its basis, the fish were exposed to endosulfan at 20, 35, and 50 μg L?1 and autopsy was done on days 1, 2, 3, 4, 7, 14, 21, 28, and 35. Lipid peroxidation was induced in a concentration-dependent manner, being highest at 50 μg L?1 (3/4 LC50–96 h, sub-lethal concentration-I, SL-I) on day 4 (720% versus control), followed in its extent (490%) at 30 μg L?1 (1/2 LC50–96 h, sub-lethal concentration-II, SL-II) on day 7 and lowest (260%) at 10 μg L?1 (1/4 LC50–96 h, sub-lethal concentration-III, SL-III) on day 14. Glutathione showed a concentration- and time-dependent elevation in the initial phase, with highest level on day 4 (180%) at SL-I, but showed significant reduction in all test concentrations from day 21 of post-exposure. Superoxide dismutase was decreased significantly throughout the study, with highest reduction (63%) on day 4 at SL-I; catalase increased in all test concentrations up to day 14 but showed a significant decrease from the day 28 of post-exposure. The potential role of these parameters as indicators of pesticide pollution in aquatic systems is discussed. 相似文献
267.
Effluents collected from tanneries in Sialkot showed considerably higher levels of heavy metals. Sodium (12 660.91 mg/L) among macronutrients and Cr (592.20 mg/L) among heavy metals were found in the highest concentrations. Effluent parameters, i.e. biological oxygen demand (BOD; 12.40), chemical oxygen demand (COD; 16.53), Cd (5.90), Cr (592.20) and Fe (18.59) were the respective times higher than Pakistan National Environmental Quality Standards and their continuous unchecked discharge into agricultural soils poses a potential risk. Mean concentrations (mg/L) of Cr (592.20), Ni (2.66), Mn (1.16), Fe (37.17), Zn (0.90), Cd (0.59) and Pb (1.18) in this study exceeded levels recorded to date from different tanning hubs in Pakistan. Factor analysis/principal components analysis (FA/PCA) for the effluent parameters resulted in six varimax factors, i.e. VF1 (salinity, electrical conductivity, total dissolved solids, chloride, phosphate, BOD and COD; including characteristic tannery effluent features), VF2 (pH, Cr and alkalinity; tanning operations), VF3 (Cd and Pb; dyeing processes), VF4 (Mn and Fe; finishing operations), VF5 (Ni; retaining processes) and VF6 (hardness, Ca and Cu; bating processes). Cluster analysis performed on metal data resulted in three clusters confirming metal–metal relations obtained either from FA/PCA or a correlation matrix. The results of this study are useful for heavy metal source apportionment, assessment of risk to peripheral soils and the future management of environments around tanneries. 相似文献
268.
The following areas are discussed in this paper: immobilisation of bacterial consortium in sol-gel; methyl parathion degradation and bioremediation applications; evaluation of indigenous bacterial isolates of contaminated soils. Bacterial strains were isolated from agricultural areas of Pakistan which were contaminated with methyl parathion. A bacterial consortium of seven (out of 64) Enterobacteriaceae isolates including Citrobacter, Enterobacter and Proteus vulgaris capable of degrading methyl parathion (enzyme activity ranging 410–675 mU mL?1 for individual isolates and 982 mU/mL for consortium) was selected and subsequently immobilised in tetraethyl orthosilicate (TEOS) and sodium-silicate-based sol-gel matrices. Cell viability of suspended and immobilised bacterial consortium was monitored using a minimal salt medium supplemented with methyl parathion. The results indicate that sol-gel immobilisation can be helpful to increase the shelf life of methyl parathion degrading bacterial strains along with preservation of biological activity for bioremediation applications in field. 相似文献
269.
Ibtihel Saidi Olfa Ben Said Jamel Ben Abdelmalek Soufiane Jouili Luis Chicharo Hamouda Beyrem 《Chemistry and Ecology》2013,29(8):746-774
ABSTRACTThe aim of this study was to assess the consequences of human impact on the characteristics of sediments heavy metal concentration, grain size and its influence on the structure of the microbial and meiofaunal community assemblages. A survey was carried out in July 2013 within six sites located in the Bizerte Lagoon (Tunisia), both downstream and upstream of industrial effluents. The highest total sediment metal concentrations were detected in stations located close to the industrial sewage discharge points. In these stations, the lowest densities of the total meiofauna (33?±?13?ind/10?cm?2) and conversely the highest densities of cultivable bacteria that are heavy metal resistant have been reported (16?±?80.34?CFU?g?1). Univariate (ANOVA) and multivariate (MDS/CCA) analyses demonstrate high dissimilarity (0.06) in meiofaunal and bacterial community structures between downstream and upstream industrial sewages. Furthermore, canonical correspondence analysis CCA results indicated that heavy metal sediment contamination promoted bacteria that are resistant to heavy metals, while heterotrophic bacteria supported the development of meiofauna taxa. The results highlight the importance of bacteria/meiofauna interactions, as both meiofaunal and microbial communities give indications of the ecological impact of heavy metal contamination in sediment. 相似文献
270.
Phenolic compounds in olive oil mill wastewaters were analysed by HRGC–MS after extracting the acidified solution with ethyl acetate and derivatization with N,O-bis(trimethylsilyl)trifluoroacetamide. Both simple and complex phenols were detected with the latter being the most abundant. 1,2-dihydroxybenzene (catechol), p-hydroxyphenyl ethanol (tyrosol), 3,4-dihydroxyphenyl ethanol (hydroxytyrosol) and 4-hydroxy-3-methoxyphenyl ethanol (homovanillyl alcohol) predominated among the simple phenols using a gas chromatograph coupled with a mass selective detector. 相似文献