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Migration of phthalates from PET water bottle in events of repeated uses and associated risk assessment Texte intégral
2020
Jayaweera, Mahesh | Perera, Hasini | Bandara, Nilanthi | Danushika, Gimhani | Gunawardana, Buddhika | Somaratne, Chandani | Manatunge, Jagath | Zoysa, Kasun | Thathsara, Thilini
Phthalates are widely used as a plasticizer in manufacturing polyethylene terephthalate (PET) bottles to improve softness, flexibility, durability, longevity, and workability. Phthalates are known in instigating profound human health hazards. In many developing countries, lack of proper disposal facilities established for empty PET bottles and the absence of legislation on reuse invariably persuade people to reuse them for storing potable water. An experiment was conducted with two commercial brands of PET bottles to explore the potential of phthalate migration when domestically refilled and reused in multiple times at two temperature conditions. Temperatures of ambient (27 ± 2 °C) and warm (60 ± 2 °C) were selected as the refilling temperatures because of the common practice by people. For both brands, only bis(2-ethylhexyl) phthalate (DEHP) levels were detected in refilled water in every event of reuse. For both brands, mean DEHP levels migrated to water at 60 ± 2 °C were significantly higher (p < 0.05) compared to those at 27 ± 2 °C. Risk analyses carried out on human health suggested that there exist no definite acute or chronic health risks when the refilled water is consumed continuously for 30 years for both temperatures. Still, such risks were higher for the consumption of refilled water of warm temperatures than those of ambient temperature. However, this study elucidates that DEHP migration would be at an alarming rate when the events of reuse of a single bottle increase so that regulations banning the reuse of empty PET bottles are paramount, especially for developing countries.
Afficher plus [+] Moins [-]First insight into polybrominated diphenyl ethers in car dust in Turkey: concentrations and human exposure implications Texte intégral
2020
Ozkaleli Akcetin, Merve | Gedik, Kadir | Balcı, Selçuk | Gul, Hatice Kübra | Birgul, Askin | Kurt Karakus, Perihan Binnur
The presence of polybrominated diphenyl ethers (PBDEs) in the car is due to their use as a flame retardant additive in various car components such as dashboard, plastic parts, seat and headliner cushion foams, insulated cables, and electronic circuits. Ingestion of dust inadvertently or dermal contact to dust are significant pathways of human exposure to pollutants including PBDEs. There are no studies documenting presence of car dust associated flame retardants in Turkey. In the current study, a total of 13 PBDEs congeners were investigated in 62 car dust samples collected from Bursa province of Turkey using glass-fiber filters and a vacuum cleaner. Results of the study showed that congener concentrations were within the range of <MDL-40198 ng/g and PBDE-209, major component of commercial deca-BDE, showed the highest concentration among the targeted congeners. Assessment of exposure to analyzed PBDEs via inadvertent dust ingestion and skin contact showed toddlers are exposed to these chemicals approx. 10 times higher compared to adults. Hazard quotient (HQ) values calculated based on total exposure (ingestion + dermal contact) and were < 1 for both adults and toddler indicated that exposure to car dust-associated PBDEs through ingestion and skin contact does not pose any health risks for human in Bursa.
Afficher plus [+] Moins [-]Compression behaviors of mechanically biologically treated wastes of Tianziling landfill in Hangzhou, China Texte intégral
2020
Zhang, Zhenying | Fang, Yuehua | Wang, Yixuan | Xu, Hui
This study aimed to investigate the compression behaviors of mechanically biologically treated (MBT) wastes. For this purpose, the short-term compression-rebound and long-term compression tests were conducted on MBT wastes collected from Hangzhou Tianziling landfill in China. The results showed that the duration of immediate compression was obtained as 15.17–36.67 h and was comparable to municipal solid waste (MSW). The immediate compression ratio was 0.233–0.247, and it was comparable to the aged high food waste content (HFWC)-MSW, fresh and aged low food waste content (LFWC)-MSW, but much lower than the fresh HFWC-MSW. The mechanical creep ratio (C′αc) was 0.012–0.018, being close to the fresh and aged MSWs. The bio-induced compression ratio (C′αb) was 0.143–0.174. The compression ratio rose exponentially with temperature (5–42 °C) in both mechanical creep stage and bio-induced compression stage, and it increased much faster in the bio-induced compression stage. The resilient strains was only 2.1–3.3% of the compression strain at the same stress interval, suggesting that the compression strain consisted of mostly plastic deformation and negligible elastic deformation. The above findings can provide a reference for settlement prediction and storage capacity estimation of an MBT waste landfill.
Afficher plus [+] Moins [-]Filter Backwash Water and Floated Residue Containing Pathogenic Protozoa: Detection Method and Treatment Alternatives Texte intégral
2020
Silva, Hugo Guilherme | Sabogal-Paz, Lyda Patricia
Treatments using ozone for filter backwash water (FBW) and calcium oxide for floated residue (FR) were evaluated adopting bench-scale testing for the inactivation of Giardia spp. cysts and Cryptosporidium parvum oocysts. The protocol chosen for protozoa detection involved following the concentration step by direct centrifugation (adding ICN 7X cleaning solution at 1.0%) and purification by immunomagnetic separation (IMS). The FR treatment with calcium oxide (dosage of 23 mg CaO 100 mL⁻¹ and 3-day contact time at 25 °C) proved to be efficient, as no parasites were detected after the treatment. The reduction of calcium oxide dosage (16 mg CaO 100 mL⁻¹ and 3-day contact time at 25 °C) was insufficient to inactivate the protozoa, since potentially viable organisms were identified using propidium iodide (PI). Concerning the disinfection conditions with ozone (5-min and 10-min contact time and dosage of 10 mg O₃ L⁻¹ and 7.5 mg O₃ L⁻¹, respectively), there was complete removal of the target organisms, as no protozoa were detected after the FBW treatment. From the results obtained, the tested treatments can be considered promising alternatives for water treatment plants (WTPs). However, the costs incurred from these treatments have to be considered.
Afficher plus [+] Moins [-]The protective effects of Terminalia laxiflora extract on hepato-nephrotoxicity induced by fipronil in male rats Texte intégral
2020
Khalaf, Abdelbaset Abdelrahem | Ibrahim, Marwa A. | Galal, Mona K. | Abdallah, Amr A. | Mansour, Ragaa | Afify, Mostafa M.
The present study was led to investigate the defensive role of Terminalia laxiflora extract (TLE) on fipronil (FPN) induced hepatotoxicity and nephrotoxicity in male rats. Rats were administered with TLE (100 mg/kg) against the renal toxicity and hepatotoxicity induced by administration of FPN (10.5 mg/kg) for 30 days. At the end of the experimental period, the serum, liver, and kidneys were harvested and assessed for subsequent analysis. FPN administration to rats resulted in a significant elevation of serum transaminases, urea, and creatinine. Also, FPN-treated groups exhibited a marked reduction in total protein and albumin levels. Compared with the control group, the level of malondialdehyde (MDA) was elevated in groups treated with FPN, whereas superoxide dismutase (SOD), catalase (CAT) activities, and glutathione levels were distinctly reduced in this group. Significant increases in genomic DNA fragmentation and the expression level of the caspase-3 gene were also recorded. The biochemical result was supported by histopathological findings. Co-administration of TLE along with FPN significantly diminished the liver and kidney function tests decreased the level of lipid peroxidation, and enhanced all the antioxidant enzymes, while also diminishing the expression of caspase-3 and DNA laddering, indicating amelioration of DNA damage. These results indicate that TLE plays a vital role in diminishing FPN-induced hepatotoxicity and nephrotoxicity.
Afficher plus [+] Moins [-]High crosslinked sodium carboxyl methylstarch-g-poly (acrylic acid-co-acrylamide) resin for heavy metal adsorption: its characteristics and mechanisms Texte intégral
2020
Zhang, Ming | Yang, Ping | Lan, Guihong | Liu, Yongqiang | Cai, Qin | Xi, Junnan
A lower expansive heavy metal adsorbent, high crosslinked sodium carboxyl methylstarch-g-poly (acrylic acid-co-acrylamide) resin (HCAA), has been prepared by enhancing the crosslinking degree of the traditional water-absorbing polymer under the graft copolymerization reaction. Further heavy metal adsorption experiments, morphology analysis, and structure characteristic observations indicate that HCAA resin has an excellent heavy metal adsorption properties for Cr³⁺, Cu²⁺, Ni²⁺, and Zn²⁺ of 80.08, 158.07, 155.71, and 137.15 mg/g, respectively. The nanoholes in network structures of HCAA resin expanding in solution provide an effective diffusion and exchange channels for heavy metal ions and Na⁺. The adsorption process of HCAA containing –COONa is attributed to ion exchange process, and its essence is to form the coordination bond with heavy metals. The adsorption capacity differences of –COO⁻ have been explained by using the coordination chemistry theory. In addition, the adsorption selectivity of an expansive adsorbent containing –COONa are heavy metals > H₂O >> Na⁺. Our research puts forward an insight that increasing the crosslinker content on the basis of the traditional super absorbent resin can obtain a lower expansive adsorbent to heavy metal pollutants.
Afficher plus [+] Moins [-]Effects of steel slag amendments on accumulation of cadmium and arsenic by rice (Oryza sativa) in a historically contaminated paddy field Texte intégral
2020
He, Huaidong | Xiao, Qingqing | Yuan, Ming | Huang, Run | Sun, Xianbin | Wang, Xiaomei | Zhao, Huaiqiong
Paddy soil contamination by cadmium (Cd) and arsenic (As) is a great concern. Field experiments were conducted to study the effects of steel slag (SS, 2.0 and 4.0 t ha⁻¹) on the solubility of Cd and As in soil and their accumulation by rice plants grown in a historically co-contaminated paddy field with Cd and As. The results showed that SS amendment (4.0 t ha⁻¹) significantly decreased soluble concentrations of Cd in pore-water but increased that of As, related to markedly elevated soil pH and soluble silicon, phosphorus of pore-water in rice rhizosphere at both heading and mature stages. The amendments also evidently decreased Cd but enhanced As in iron plaque on root surfaces, while the formation of iron plaque was not significantly increased. Further, SS amendment (4.0 t ha⁻¹) markedly reduced Cd concentrations in rice tissues (roots, straw, and brown rice) by 48–78% at both stages, though increased As by 13–38%. Cadmium translocation from roots to aerial parts decreased significantly after the amendments, but not for As. Besides, SS application increased the biomass of roots, straw and grains, and root antioxidant enzyme activities. Collectively, steel slag decreased Cd accumulation in rice tissues and in iron plaque but increased those of As, likely due to steel slag decreasing soluble Cd and enhancing soluble As in pore-water, related to soil pH and soluble nutrients (Si, P), and restraining Cd translocation within rice. Our results indicate that steel slag represents a favorable potential for Cd-contaminated paddy soils, though it seems undesirable for Cd and As co-contamination.
Afficher plus [+] Moins [-]Biosurfactant electrospun nanofibers exhibit minimal side effects on the structure and function of the liver tissue in male rat model Texte intégral
2020
Ebaid, Hossam Abd Rabou | Abdel-Mageed, Ahmed | Al-Tamimi, Jameel Homoud | Hassan, Iftekhar | Rady, Ahmed Mostafa | El-Newehy, Mohamed Hassan | Mashaly, Ashraf Mohamed | Abdel-Megeed, Ahmed AbdelFattah Mahmoud | Alhazza, Ibrahim | Abdel-Halim, Essam Sayed | Salem, Abdelfattah Zeidan Mohamed
Oil spills can result in significant damage to marine estuaries, rivers, lakes, wetlands, and shorelines. Electrospun nanofibers containing biosurfactant (ENFs) can be used to clean oil spills up and protect the environmental biology. Present work aimed to study the side-effects of prepared nanofibers on animal models. Screening of the prepared ECNFs on animals showed that three of them (PVA-5, PEO-1, and PEO-5) are safe to hepatic tissues and liver functions. Furthermore, oxidative stress did not change after using these nanofibers. The PVA-1 nanofibers, however, were found to cause major pathological changes in the liver tissue. In addition, PVA-1 nanofibers were proved to alter the total white blood count and the neutrophil percentages significantly in comparison to the control. In conclusion, PVA-5, PEO-1, and PEO-5 are safe to hepatic tissues and liver functions.
Afficher plus [+] Moins [-]Ultrafiltered biopulping strategy for the production of good quality pulp and paper from sugarcane bagasse Texte intégral
2020
Varghese, Libin Mathew | Nagpal, Raksha | Avtar Singh, | Miśra, Omaprakāśa | Bhardwaj, Nishi Kant | Mahajan, Ritu
This research was carried out with an objective to examine the efficacy of ultrafiltered xylano-pectinolytic enzymes in pulping of sugarcane bagasse. Maximum biopulping was achieved with enzyme dose of xylanase (175 IU / g bagasse) and pectinase (75 IU / g bagasse) at treatment period of 180 min. The temperature, pH, and bagasse to liquid ratio for biopulping experiments were kept constant at 55ᵒ C, 8.5, and 1:10 (g/ml), respectively. The ultrafiltered biopulping improved chemical pulping, resulted in 25.11%, 9.17% increase in brightness, unscreened pulp production and 11.81, 59.50, and 49.14% decrease in total solids, rejections. and kappa number, respectively. The bagasse biopulping also resulted in 15% decrease of alkali load to attain similar kappa number and optical properties as obtained under 100% alkali dosage. Ultrafiltered biopulped-unbleached samples showed significant increase in breaking length (13.55%), burst index (40.21%), tear index (19.04%), double fold (42.5%), Gurley porosity (28.21%) and viscosity (13.37%) in comparison with non-enzymatically treated control pulp samples. In comparison with non biotreated-bleached pulp samples, ultrafiltered biopulped-bleached samples also resulted in higher burst index (56.80%), breaking length (17.38%), double fold (39.58%), tear index (3.38%), viscosity (30.68%), and Gurley porosity (52.50%). This environmentally sustainable ultrafiltered biopulping approach for sugarcane bagasse has the potential to decrease the demand of chemicals, ultimately pollution along with enhance the quality of paper.
Afficher plus [+] Moins [-]Immobilization of horseradish peroxidase on Fe3O4 nanoparticles for enzymatic removal of endocrine disrupting chemicals Texte intégral
2020
Xiao, Feng | Xiao, Ping | Jiang, Wei | Wang, Dongsheng
The modified Fe₃O₄ nanoparticles were used as a support for the immobilization of horseradish peroxidase (HRP). The immobilized enzyme (HRP@Fe₃O₄) was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectrometer (FTIR), and vibration sample magnetometer (VSM). According to the results, the optimum concentration of glutaraldehyde (GA) and agitation time were 300 μL and 7 h. HRP was well loaded on the surface of the Fe₃O₄. There was no change in the crystal structure of HRP@Fe₃O₄ compared with Fe₃O₄. The removals of bisphenol A (BPA) and 17α-ethinylestradiol (EE2) using HRP@Fe₃O₄ had been investigated. The degradation efficiencies of BPA and EE2 catalyzed by HRP@Fe₃O₄ were higher than that of soluble HRP. In addition, HRP@Fe₃O₄ can be reused through magnetic separation. After the fifth repeated use, the removal efficiencies of BPA and EE2 were up to 56% and 48%, respectively. Batch studies of catalyzed oxidation and coagulation on the degradation of BPA and EE2 in the presence of humic acid (HA) were also investigated. The order of the removal efficiencies was HRP+PACl (polyaluminum chloride)+SDS (lauryl sodium sulfate)>HRP+PACl>HRP>HRP+PAM (Polyacrylamide)>HRP+PAM+SDS. The coagulation effect of HRP@Fe₃O₄ and PACl was better than that of HRP@Fe₃O₄ and PAM. The removals of BPA and EE2 were 90.3% and 64.5% by use HRP@Fe₃O₄ and PACl as coagulant, while the removals were 78.7% and 57.6% by use HRP@Fe₃O₄ and PAM as coagulant. SDS had a positive effect on PACl, while a negative effect on PAM. Moreover, the products generated by enzymatic oxidation reaction can be effectively removed after coagulation.
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