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Results 2441-2450 of 3,197
New isotopic evidence of lead contamination in wheat grain from atmospheric fallout
2015
Yang, Jun | Chen, Tongbin | Lei, Mei | Zhou, Xiaoyong | Huang, Qifei | Ma, Chuang | Gu, Runyao | Guo, Guanghui
Crops could accumulate trace metals by soil-root transfer and foliar uptake from atmospheric fallout, and an accurate assessment of pollution sources is a prerequisite for preventing heavy metal pollution in agricultural products. In this study, we examined Pb isotope rates to trace the sources of Pb in wheat grain grown in suburbs. Results showed that, even in zones with scarcely any air pollution spots, atmospheric fallout was still a considerable source of Pb accumulation in wheat. The concentration of Pb in wheat grain has poor correlation with that in farm soil. The Pb concentration in wheat grains with dust in bran coat was significantly higher than that in wheat grains, which indicates that Pb may accumulate by foliar uptake. The Pb isotope rate has obvious differences between the soil and atmospheric fallout, and scatter ratio is significantly closer between the wheat grain and atmospheric fallout. Atmospheric fallout is a more significant source of Pb concentration in wheat grains than in soil. As far as we know, this is the first study on the main sources of lead in grain crop (wheat) samples with isotope. This study aims to improve our understanding of the translocation of foliar-absorbed metals to nonexposed parts of plants.
Show more [+] Less [-]Improvement of anaerobic digestion of waste-activated sludge by using H2O2 oxidation, electrolysis, electro-oxidation and thermo-alkaline pretreatments
2015
Feki, Emna | Khoufi, Sonia | Loukil, Slim | Sayadi, Sami
Disintegration of municipal waste-activated sludge (WAS) is regarded as a prerequisite of the anaerobic digestion process to reduce sludge volume and improve biogas yield. Pretreatment of WAS using thermo-alkaline (TA), H₂O₂ oxidation, electrolysis and electro-oxidation (EO) processes were investigated and compared in term of COD solubilization and biogas production. For each pretreatment, the influences of different operational variables were studied in detail. At optimum conditions, EO gave the maximum COD solubilization (28 %). The effects of pretreatments under the optimum conditions on anaerobic digestion were experienced with biochemical methane potential assay. Significant increases in biogas yield up to 78 and 40 % were observed respectively in the EO and TA pretreated samples compared to raw sludge. Results clearly revealed that the application of EO is a significant alternative method for the improvement of WAS anaerobic digestion.
Show more [+] Less [-]Prevalence of liver diseases as referred by people living in the Santos and São Vicente Estuary
2015
Carvalho, Daniele Fernandes Pena | Guimarães, M. T. | Ribeiro, T. S. | Campina, N. N. | Lobarinhas, M. R. | Lopes, A. L J | Cunha, M. G. | Souza, I. B. | Oliveira, V. L. F. | Braga E Braga, L. | Martins, L. C. | Gomes, A. | Pereira, L. A. A. | Braga, A. L. F.
The Santos and São Vicente Estuary has suffered extensively over the years from irregular industrial deposits. The present study aimed to evaluate liver disease prevalence and potential associated risk factors in four of the Estuary’s areas (Pilões and Água-Fria, Cubatão Center, Continental São Vicente, and Guarujá) and a reference area (Bertioga). This study consisted of a cross-sectional study design, in which a questionnaire was used to collect information in 820 households at each of the study areas. The proportion of total liver diseases, hepatitis, cirrhosis, and cancer (liver, biliary tract, and pancreas) per area were estimated. Pearson’s chi-square test and two proportion differences test were applied in order to evaluate associations between disease occurrence and areas and to test differences between two proportions, respectively. Single and multiple logistic regression models were applied to assess associations between disease prevalence and the different study areas. Liver disease prevalence was 1.5 % among all inhabitants and 1.4 % among those without any type of exposure. Among those who reported the presence of liver disease, a higher percentage of the participants that reported hepatitis (27.7 %) or other liver disease (48.7 %) did not report occupational or alcohol exposures. Hepatitis (77.8 %) was the most reported disease, and a statistical association between living in Pilões and Água-Fria and the occurrence of hepatitis was observed (Pearson’s χ ²: z = 18.1; p = 0.001). The consumption of locally-produced groceries (2.88; CI: 1.24–6.70) and water (5.88; CI: 2.24–15.45) were shown to be risk factors for the occurrence of liver disease. Thus, environmental exposure is still a public health problem present in the estuary region.
Show more [+] Less [-]Endolithic microbial communities in carbonate precipitates from serpentinite-hosted hyperalkaline springs of the Voltri Massif (Ligurian Alps, Northern Italy)
2015
Quéméneur, Marianne | Palvadeau, Alexandra | Postec, Anne | Monnin, Christophe | Chavagnac, Valérie | Ollivier, Bernard | Erauso, Gaël
The Voltri Massif is an ophiolitic complex located in the Ligurian Alps close to the city of Genova (Northern Italy) where several springs discharge high pH (up to 11.7), low salinity waters produced by the active serpentinization of the ultramafic basement. Mixing of these hyperalkaline waters with the river waters along with the uptake of atmospheric carbon dioxide forms brownish carbonate precipitates covering the bedrock at the springs. Diverse archaeal and bacterial communities were detected in these carbonate precipitates using 454 pyrosequencing analyses of 16S ribosomal RNA (rRNA) genes. Archaeal communities were dominated by members of potential methane-producing and/or methane-oxidizing Methanobacteriales and Methanosarcinales (Euryarchaeota) together with ammonia-oxidizing Nitrososphaerales (Thaumarchaeota) similar to those found in other serpentinization-driven submarine and terrestrial ecosystems. Bacterial communities consisted of members of the Proteobacteria, Actinobacteria, Planctomycetes, Bacteroidetes, Chloroflexi, and Verrucomicrobia phyla, altogether accounting for 92.2 % of total retrieved bacterial 16S rRNA gene sequences. Amongst Bacteria, potential chemolithotrophy was mainly associated with Alpha- and Betaproteobacteria classes, including nitrogen-fixing, methane-oxidizing or hydrogen-oxidizing representatives of the genera Azospirillum, Methylosinus, and Hydrogenophaga/‘Serpentinomonas’, respectively. Besides, potential chemoorganotrophy was attributed mainly to representatives of Actinobacteria and Planctomycetales phyla. The reported 16S rRNA gene data strongly suggested that hydrogen, methane, and nitrogen-based chemolithotrophy can sustain growth of the microbial communities inhabiting the carbonate precipitates in the hyperalkaline springs of the Voltri Massif, similarly to what was previously observed in other serpentinite-hosted ecosystems.
Show more [+] Less [-]Modeling the transfer of arsenic from soil to carrot (Daucus carota L.)—a greenhouse and field-based study
2015
Ding, Changfeng | Zhou, Fen | Li, Xiaogang | Zhang, Taolin | Wang, Xingxiang
Reliable empirical models describing arsenic (As) transfer in soil-plant systems are needed to estimate the human As burden from dietary intake. A greenhouse experiment was conducted in parallel with a field trial located at three sites through China to develop and validate soil-plant transfer models to predict As concentrations in carrot (Daucus carota L.). Stepwise multiple linear regression relationships were based on soil properties and the pseudo total (aqua regia) or available (0.5 M NaHCO₃) soil As fractions. Carrot As contents were best predicted by the pseudo total soil As concentrations in combination with soil pH and Fe oxide, with the percentage of variation explained being up to 70 %. The constructed prediction model was further validated and improved to avoid overprotection using data from the field trial. The final obtained model is of great practical relevance to the prediction of As uptake under field conditions.
Show more [+] Less [-]The cyanobacterium Synechocystis sp. PUPCCC 62: a potential candidate for biotransformation of Cr(VI) to Cr(III) in the presence of sulphate
2015
Parveen, Shahnaz | Khattar, J. I. S. | Singh, D. P.
The cyanobacterium Synechocystis sp., an isolate from polluted water of Satluj river, India, was found resistant to chromium(VI) up to 200 nmol mL⁻¹. In this study, it has been demonstrated that this organism takes up Cr(VI) through a phosphate transporter. The organism removed 250 nmol Cr(VI), 210 nmol phosphate and 180 nmol sulphate mg⁻¹ protein from a buffer solution in 8 h. Cr(VI) uptake by the organism decreased to 135 nmol Cr(VI) removed per milligram protein in the presence of 200 nmol phosphate mL⁻¹, but the same concentration of sulphate did not affect the Cr(VI) uptake. Similarly, the presence of Cr(VI) in the solution affected the phosphate uptake but not sulphate uptake by the test organism. The kinetic studies on Cr(VI) uptake in the presence of phosphate revealed that phosphate and Cr(VI) acted as competitive inhibitors for one another. Phosphate-starved cells of the organism removed more amount of Cr(VI) than the basal medium-grown cells. The uptake of Cr(VI) as well as phosphate by the organism was observed to be a light-dependent process. Cinnamic acid, a phosphate transporter inhibitor, inhibited Cr(VI) uptake by the organism. Results clearly demonstrated that the test organism takes up chromate ions by phosphate transporter and not by the sulphate transporter. This organism is thus a potential candidate for the bioremediation of Cr(VI) from Cr(VI) and sulphate-laden water.
Show more [+] Less [-]Occurrence and risk assessment of selected phthalates in drinking water from waterworks in China
2015
Liu, Xiaowei | Shi, Jianghong | Bo, Ting | Li, Huiyuan | Crittenden, John C.
The first nationwide survey of six phthalates (diethyl phthalate (DEP); dimethyl phthalate (DMP); di-n-butyl phthalate (DBP); butyl benzyl phthalate (BBP); bis(2-ethylhexyl) phthalate (DEHP); din-octyl phthalate (DnOP)) in drinking waters from waterworks was conducted across seven geographical zones in China. Of the six target phthalates, DBP and DEHP were the highest abundant phthalates with median (± interquartile range) values of 0.18 ± 0.47 and 0.18 ± 0.97 μg/L, respectively, but did not exceed the limit values in China’s Standards for Drinking Water Quality. These phthalates in drinking water were generally higher in the northern regions of China than those in the southern and eastern regions. Based on the investigated concentrations, lifetime exposure risk assessment indicated that phthalates in drinking water did not pose carcinogenic and noncarcinogenic risks to Chinese residents, even under the conservative scenario (with 95th percentile risk). In addition, we found that DEHP contributed the greatest risk to the total exposure risk of all the selected phthalates and oral ingestion was the main exposure route for phthalates in drinking water.
Show more [+] Less [-]Combined use of PAH levels and EROD activities in the determination of PAH pollution in flathead mullet (Mugil cephalus) caught from the West Black Sea coast of Turkey
2015
Bozcaarmutlu, Azra | Sapmaz, Canan | Kaleli, Gizem | Turna, Sema | Yenisoy-Karakaş, Serpil
The aim of this study was to determine the extent of polycyclic aromatic hydrocarbon (PAH) pollution by measuring PAH levels and 7-ethoxyresorufin-O-deethylase (EROD) activities in flathead mullet (Mugil cephalus) samples caught from the West Black Sea coast of Turkey. The fish samples were caught in August 2008–2011. The levels of 13 PAHs were measured by high-performance liquid chromatography (HPLC) in the liver of fish. Most of the measured PAHs had three rings (low molecular weight). The frequencies of detection of PAHs were higher in fish samples caught from Zonguldak Harbour and Gülüç Stream Mouth than those from Sakarya River Mouth, Amasra and Kefken. EROD activities and cytochrome P4501A (CYP1A) protein level were also measured in the fish liver microsomes. Highly elevated EROD activities and CYP1A levels were measured in the mullet samples caught from Zonguldak Harbour and Gülüç Stream than those from Amasra and Kefken. The detection of PAHs in the liver of fish samples shows recent exposure to PAHs. The chemical analyses of PAHs and EROD activity results together reflected the extent of PAH pollution in the livers of fish caught from the West Black Sea coast of Turkey. The results indicate that Zonguldak Harbour is the most polluted site in the West Black Sea coast of Turkey.
Show more [+] Less [-]Ornamental plants for micropollutant removal in wetland systems
2015
Macci, Cristina | Peruzzi, Eleonora | Doni, Serena | Iannelli, Renato | Masciandaro, Grazia
The objective of this paper was to evaluate the efficiency of micropollutant removal, such as Cu, Zn, carbamazepine, and linear alkylbenzene sulfonates (LAS), through the use of a subsurface vertical flow constructed wetland system with ornamental plants. Zantedeschia aethiopica, Canna indica, Carex hirta, Miscanthus sinensis, and Phragmites australis were selected and planted in lysimeters filled up with gravel. The lysimeters were completely saturated with synthetic wastewater (N 280 mg L⁻¹, P 30 mg L⁻¹, Cu 3.6 mg L⁻¹, Zn 9 mg L⁻¹, carbamazepine 5 μg L⁻¹, linear alkylbenzene sulfonates 14 mg L⁻¹), and the leaching water was collected for analysis after 15, 30, and 60 days in winter-spring and spring-summer periods. Nutrients (N and P) and heavy metals decreased greatly due to both plant activity and adsorption. C. indica and P. australis showed the highest metal content in their tissues and also the greatest carbamazepine and LAS removal. In these plants, the adsorption/degradation processes led to particularly high oxidative stress, as evidenced by the significantly high levels of ascorbate peroxidase activity detected. Conversely, Z. aethiopica was the less efficient plant in metal and organic compound removal and was also less stressed in terms of ascorbate peroxidase activity.
Show more [+] Less [-]Polybrominated diphenyl ethers in air and fallouts from an e-waste polluted region in southeast China: insight into levels, compositional profiles, and seasonal variation
2015
Xu, Feng | Zhang, Gang | Wang, Junxia | Zhang, Wei | Liu, Lili | Lin, Kuangfei
Air and fallout samples were collected seasonally in an e-waste polluted region in southeast of China in 2013–2014. The annual polybrominated diphenyl ethers (PBDEs) concentrations in air and fallout samples were 200 ± 162 pg m⁻³ and 320 ± 255 ng g⁻¹, respectively. The deposition flux calculated from the fallout concentration was 110 ± 77.3 ng m⁻² day⁻¹. The PBDE levels and deposition fluxes of the samples deployed within the e-waste central area were three to four times higher than those in the surrounding area. The congener profiles in the air samples could be commonly found in commercial penta-BDE mixtures. BDE209 was the most dominant congener in fallout samples. Debromination processes were confirmed to occur both in the air and fallouts due to the minor amounts or inexistence of some congeners in technical PBDE products. The highest gaseous PBDE concentration was found during the summer while lowest during the autumn. PBDE concentration in fallouts turned up higher in the cold months while lower in the warm months. The similarity of deposition fluxes at sites in the e-waste central area indicated a steady PBDE emission source, whereas the significant relationship between deposition fluxes and particle weights at sites in the e-waste surrounding area suggested the scavenging of PBDEs in this area was largely associated with particles.
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