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Resultados 291-300 de 4,042
Cd isotope fractionation during simulated and natural weathering Texto completo
2016
Zhang, Yuxu | Wen, Hanjie | Zhu, Chuanwei | Fan, Haifeng | Luo, Chongguang | Liu, Jie | Cloquet, Christophe
In practice, stable Cd isotope ratios are being applied to trace pollution sources in the natural environment. However, Cd isotope fractionation during weathering processes is not yet fully understood. We investigated Cd isotope fractionation of PbZn ore in leaching experiments and in the environment under natural weathering processes. Our leaching experiments demonstrated that the leachate was enriched with heavy Cd isotopes, relative to initial and residual samples (Δ114/110Cdleachate − initial state = 0.40–0.50‰, Δ114/110Cdleachate −residual state = 0.36–0.53‰). For natural samples, δ114/110Cd values of stream sediments were higher than those of the corresponding soil samples collected from the riverbank, Δ114/110Cdstream sediment −soil can be up to 0.50‰. This observation is consistent with our leaching experiments, which indicate significant Cd isotope fractionation during natural weathering processes. Therefore, natural contributions should be considered when using Cd isotopes to trace anthropogenic pollution in water and sediment systems.
Mostrar más [+] Menos [-]Use of sunlight to degrade oxytetracycline in marine aquaculture's waters Texto completo
2016
Leal, J.F. | Esteves, V.I. | Santos, E.B.H.
Oxytracycline (OTC) is a broad spectrum antibiotic authorized for use in European aquaculture. Its photo-degradation has been widely studied in synthetic aqueous solutions, sometimes resorting to expensive methods and without proven effectiveness in natural waters. Thus, this work studied the possibility to apply the solar photo-degradation for removal of OTC from marine aquaculture's waters. For that, water samples were collected at different locals of the water treatment circuit, from two different aquaculture companies. Water samples were firstly characterized regarding to pH, salinity, total suspended solids (TSS), organic carbon and UV–Vis spectroscopic characteristics. Then, the samples were spiked with OTC and irradiated using simulated sunlight in order to evaluate the matrix effects on OTC photo-degradation. From kinetic results, the apparent quantum yields and the outdoor half-life times, at 40°N for midsummer and midwinter days were estimated by the first time for these conditions. For a midsummer day, at sea level, the outdoor half-life time predicted for OTC in these aquaculture's waters ranged between 21 and 25 min. Additionally, the pH and salinity effects on the OTC photo-degradation were evaluated and it has been shown that high pH values and the presence of sea salt increase the OTC photo-degradation rate in aquaculture's waters, compared to results in deionised water. The results are very promising to apply this low-cost methodology using the natural sunlight in aquaculture's waters to remove OTC.
Mostrar más [+] Menos [-]Health risk assessment for exposure to nitrate in drinking water from village wells in Semarang, Indonesia Texto completo
2016
Sadler, Ross | Maetam, Brooke | Edokpolo, Benjamin | Connell, Des | Yu, Jimmy | Stewart, Donald | Park, M.-J. | Gray, Darren | Laksono, Budi
The levels of nitrate in 52 drinking water wells in rural Central Java, Indonesia were evaluated in April 2014, and the results were used for a health risk assessment for the local populations by using probabilistic techniques. The concentrations of nitrate in drinking water had a range of 0.01–84 mg/L, a mean of 20 mg/L and a medium of 14 mg/L. Only two of the 52 samples exceeded the WHO guideline values of 50 mg/L for infant methaemoglobinaemia. The hazard quotient values as evaluated against the WHO guideline value at the 50 and 95 percentile points were HQ50 at 0.42 and HQ95 at 1.2, respectively. These indicated a low risk of infant methaemoglobinaemia for the whole population, but some risk for the sensitive portion of the population. The HQ50 and HQ95 values based on WHO acceptable daily intake dose for adult male and female were 0.35 and 1.0, respectively, indicating a generally a low level of risk. A risk characterisation linking birth defects to nitrate levels in water consumed during the first three months of pregnancy resulted in a HQ50/50 values of 1.5 and a HQ95/5 value of 65. These HQ values indicated an elevated risk for birth defects, in particular for the more sensitive population. A sanitation improvement program in the study area had a positive effect in reducing nitrate levels in wells and the corresponding risk for public health. For example, the birth defect HQ50/50 values for a subset of wells surveyed in both 2014 and 2015 was reduced from 1.1 to 0.71.
Mostrar más [+] Menos [-]Country-specific chemical signatures of persistent organic pollutants (POPs) in breast milk of French, Danish and Finnish women Texto completo
2016
Antignac, J.P. | Main, K.M. | Virtanen, H.E. | Boquien, C.Y. | Marchand, P. | Venisseau, A. | Guiffard, I. | Bichon, E. | Wohlfahrt-Veje, C. | Legrand, A. | Boscher, C. | Skakkebaek, Niels E. | Toppari, J. | Le Bizec, B.
Country-specific chemical signatures of persistent organic pollutants (POPs) in breast milk of French, Danish and Finnish women Texto completo
2016
Antignac, J.P. | Main, K.M. | Virtanen, H.E. | Boquien, C.Y. | Marchand, P. | Venisseau, A. | Guiffard, I. | Bichon, E. | Wohlfahrt-Veje, C. | Legrand, A. | Boscher, C. | Skakkebaek, Niels E. | Toppari, J. | Le Bizec, B.
The present study compares concentrations and chemical profiles of an extended range of persistent organic pollutants (dioxins, polychlorobiphenyls, brominated flame retardants and organochlorine pesticides) in breast milk samples from French (n = 96), Danish (n = 438) and Finnish (n = 22) women. Median exposure levels observed in French women (WHO-TEQ2005 PCDD/F = 6.1 pg/g l.w., WHO-TEQ2005 dl-PCB = 4.3 pg/g l.w., sum of 6 ndl-PCB = 85.2 ng/g l.w., sum of 7 i-PBDE = 1.5 ng/g l.w.) appeared overall lower than in Danish and Finnish women for all examined POPs, except for α-HBCD (2-fold higher level at 0.6 ng/g l.w.). Furthermore, the observed exposure levels of dioxins and PCBs were higher in Danish women (WHO-TEQ2005 PCDD/F = 13.2 pg/g l.w., WHO-TEQ2005 dl-PCB = 6.6 pg/g l.w., sum of 6 ndl-PCB = 162.8 ng/g l.w.) compared to Finnish women (WHO-TEQ2005 PCDD/F = 9.0 pg/g l.w., WHO-TEQ2005 dl-PCB = 4.6 pg/g l.w., sum of 6 ndl-PCB = 104.0 ng/g l.w.), whereas the concentrations of PBDEs were similar for Danish and Finnish women (sum of 7 i-PBDE = 4.9 and 5.2 ng/g l.w. respectively). The organochlorine (OC) pesticide contamination profile, determined in a subset of French samples, was dominated by p,p’-DDE (56.6%), followed by β-HCH (14.2%), HCB (9.7%) and dieldrin (5.2%), while other compounds were only minor contributors (<5%). The three countries appeared to be discriminated by the observed contamination patterns of the PCDD/F versus PCB, and the 1,2,3,6,7,8-HxCDD versus 1,2,3,4,7,8-HxCDD ratios, in addition to the relative contributions of specific congeners to the contamination profile (PCBs #118 and #156, PBDEs #28, #47, #99 and #153). In conclusion, unique chemical signatures were observed for each country on the basis of some POP congeners. Future biomonitoring studies will need to consider the high variability of individual exposure profiles in relation to multiple exposure sources but also physiological and metabolic differences.
Mostrar más [+] Menos [-]Country-specific chemical signatures of persistent organic pollutants (POPs) in breast milk of French, Danish and Finnish women | Country-specific chemical signatures of persistent organic pollutants (POPs) in breast milk of French, Danish and Finnish women: Country-specific chemical signatures of persistent organic pollutants (POPs) in breast milk of French, Danish and Finnish women Texto completo
2016
Antignac, Jean-Philippe | Main, K. M. | Virtanen, H. E. | Boquien, Clair-Yves | Marchand, P. | Vénisseau, A. | Guiffard, I. | Bichon, E. | Wohlfahrt-Veje, C. | Legrand, A. | Boscher, C. | Skakkebæk, Niels E. | Toppari, J. | Le Bizec, B. | Laboratoire d'étude des Résidus et Contaminants dans les Aliments (LABERCA) ; École nationale vétérinaire, agroalimentaire et de l'alimentation Nantes-Atlantique (ONIRIS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | Copenhagen University Hospitals [Copenhague] | University of Turku | Physiopathologie des Adaptations Nutritionnelles (PhAN) ; Université de Nantes - UFR de Médecine et des Techniques Médicales (UFR MEDECINE) ; Université de Nantes (UN)-Université de Nantes (UN)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | Centre de Recherche en Nutrition Humaine | LUNAM Université [Nantes Angers Le Mans] | Centre Hospitalier Universitaire de Nantes = Nantes University Hospital (CHU Nantes)
International audience | The present study compares concentrations and chemical profiles of an extended range of persistent organic pollutants (dioxins, polychlorobiphenyls, brominated flame retardants and organochlorine pesticides) in breast milk samples from French (n = 96), Danish (n = 438) and Finnish (n = 22) women. Median exposure levels observed in French women (WHO-TEQ2005 PCDD/F = 6.1 pg/g l.w., WHO-TEQ2005 dl-PCB = 4.3 pg/g l.w., sum of 6 ndl-PCB = 85.2 ng/g l.w., sum of 7 i-PBDE = 1.5 ng/g l.w.) appeared overall lower than in Danish and Finnish women for all examined POPs, except for α-HBCD (2-fold higher level at 0.6 ng/g l.w.). Furthermore, the observed exposure levels of dioxins and PCBs were higher in Danish women (WHO-TEQ2005 PCDD/F = 13.2 pg/g l.w., WHO-TEQ2005 dl-PCB = 6.6 pg/g l.w., sum of 6 ndl-PCB = 162.8 ng/g l.w.) compared to Finnish women (WHO-TEQ2005 PCDD/F = 9.0 pg/g l.w., WHO-TEQ2005 dl-PCB = 4.6 pg/g l.w., sum of 6 ndl-PCB = 104.0 ng/g l.w.), whereas the concentrations of PBDEs were similar for Danish and Finnish women (sum of 7 i-PBDE = 4.9 and 5.2 ng/g l.w. respectively). The organochlorine (OC) pesticide contamination profile, determined in a subset of French samples, was dominated by p,p’-DDE (56.6%), followed by β-HCH (14.2%), HCB (9.7%) and dieldrin (5.2%), while other compounds were only minor contributors (<5%). The three countries appeared to be discriminated by the observed contamination patterns of the PCDD/F versus PCB, and the 1,2,3,6,7,8-HxCDD versus 1,2,3,4,7,8-HxCDD ratios, in addition to the relative contributions of specific congeners to the contamination profile (PCBs #118 and #156, PBDEs #28, #47, #99 and #153). In conclusion, unique chemical signatures were observed for each country on the basis of some POP congeners. Future biomonitoring studies will need to consider the high variability of individual exposure profiles in relation to multiple exposure sources but also physiological and metabolic differences.
Mostrar más [+] Menos [-]Screening and health risk of organic micropollutants in rural groundwater of Liaodong Peninsula, China Texto completo
2016
Li, Xuehua | Shang, Xiaochen | Luo, Tianlie | Du, Xu | Wang, Ya | Xie, Qing | Matsuura, Naoki | Chen, Jingwen | Kadokami, Kiwao
Groundwater serves as a main drinking water source for rural residents in China. However, little is known regarding the pollution of organic micropollutants in groundwater that may pose health risks. In this study, more than 1300 organic micropollutants were screened in the groundwater samples collected from 13 drinking water wells distributed across five rural regions of Liaodong Peninsula in China. A total of 80 organic micropollutants including 12 polycyclic aromatic hydrocarbons, 11 alkanes, 9 pesticides, 7 substituted phenols, 7 perfluoroalkyl acids, 6 heterocyclic compounds, 5 alcohols, 5 phthalic acid esters, 5 pharmaceutical and personal care products, 3 ketones, 2 polychlorinated biphenyls (PCBs), 2 alkylbenzenes and 2 chlorinated benzenes were detected, with their total concentration of 32–1.5 × 104 ng/L. Noncarcinogenic and carcinogenic risks of a part of pollutants were assessed. Exposure through skin absorption and oral ingestion was considered in the assessment. Generally the risks are within the acceptable limits, except for that the carcinogenic risk at two sites in Jinzhou is higher than 10−6. To the best of our knowledge, this is the first report on health risks of groundwater micropollutants in China.
Mostrar más [+] Menos [-]Air quality impacts of a CicLAvia event in Downtown Los Angeles, CA Texto completo
2016
Shu, Shi | Batteate, Christina | Cole, Brian | Froines, John R. | Zhu, Yifang
CicLAvia in Los Angeles, CA is the open streets program that closes streets to motorized vehicles and invites people to walk, run, play or ride their bicycles on these streets, allowing them to experience the city in a new way and get exercise at the same time. Since the events reduce the motorized traffic flow, which is a significant source of air pollution, on the streets, it is reasonable to hypothesize that the CicLAvia events can reduce the concentrations of traffic-emitted air pollutants during the road closure. This study is the first experiment to test this hypothesis. The on-road and community-wide ultrafine particle (UFP) and PM2.5 were measured on the Event-Sunday (October 5th, 2014) and the Pre- and Post- Sundays (September 28ᵗʰ and October 12ᵗʰ, 2014). Data analysis results showed the on-road UFP and PM2.5 reduction was 21% and 49%, respectively, and the community-wide PM2.5 reduction was 12%.
Mostrar más [+] Menos [-]Bioaccumulation of PCB-153 and effects on molecular biomarkers acetylcholinesterase, glutathione-S-transferase and glutathione peroxidase in Mytilus galloprovincialis mussels Texto completo
2016
Vidal-Liñán, Leticia | Bellas, Juan | Soriano, José Antonio | Concha-Graña, Estefanía | Muniategui, Soledad | Beiras, Ricardo
Bioaccumulation of PCB-153 and effects on molecular biomarkers acetylcholinesterase, glutathione-S-transferase and glutathione peroxidase in Mytilus galloprovincialis mussels Texto completo
2016
Vidal-Liñán, Leticia | Bellas, Juan | Soriano, José Antonio | Concha-Graña, Estefanía | Muniategui, Soledad | Beiras, Ricardo
In this study, PCB-153 bioaccumulation kinetics and concentration-response experiments were performed employing wild Mytilus galloprovincialis mussels. In addition, the activity of three enzymatic biomarkers: glutathione S-transferase (GST), glutathione peroxidase (GPx) and acetylcholinesterase (AChE), were measured in the mussel gills. The experimental data fitted well to an asymptotic accumulation model with a high bioconcentration factor (BCF) of 9324 L kg−1 and a very limited depuration capacity, described by a low excretion rate coefficient (Kd = 0.083 d−1). This study reports by first time in mussels significant inhibition of GST activity and significant induction of GPx activity as a result of exposure to dissolved PCB-153. In contrast, AChE activity was unaffected at all concentrations and exposure times tested. The effects on both enzymes are time-dependent, which stresses the difficulties inherent to the use of these biomarkers in chemical pollution monitoring programs.
Mostrar más [+] Menos [-]Bioaccumulation of PCB-153 and effects on molecular biomarkers acetylcholinesterase, glutathione-S-transferase and glutathione peroxidase in Mytilus galloprovincialis mussels Texto completo
2016
Vidal-Liñán, Leticia | Bellas, Juan | Soriano-Sanz, José Antonio | Concha-Graña, Estefanía | Muniategui-Lorenzo, Soledad | Beiras, Ricardo
In this study, PCB-153 bioaccumulation kinetics and concentration-response experiments were performed employing wild Mytilus galloprovincialis mussels. In addition, the activity of three enzymatic biomarkers: glutathione S-transferase (GST), glutathione peroxidase (GPx) and acetylcholinesterase (AChE), were measured in the mussel gills. The experimental data fitted well to an asymptotic accumulation model with a high bioconcentration factor (BCF) of 9324 L Kg-1 and a very limited depuration capacity, described by a low excretion rate coefficient (Kd = 0.083 d-1). This study reports by first time in mussels significant inhibition of GST activity and significant induction of GPx activity as a result of exposure to dissolved PCB-153. In contrast, AChE activity was unaffected at all concentrations and exposure times tested. The effects on both enzymes are time-dependent, which stresses the difficulties inherent to the use of these biomarkers in chemical pollution monitoring programs. | SI
Mostrar más [+] Menos [-]Positive associations of serum perfluoroalkyl substances with uric acid and hyperuricemia in children from Taiwan Texto completo
2016
Qin, Xiao-Di | Qian, Zhengmin | Vaughn, Michael G. | Huang, Jin | Ward, Patrick | Zeng, Xiao-Wen | Zhou, Yang | Zhu, Yu | Yuan, Bing | Li, Meng | Bai, Zhipeng | Paul, Gunther | Hao, Yuan-Tao | Chen, Wen | Chen, Pau-Chung | Dong, Guang-Hui | Lee, Yungling Leo
To investigate the risk of hyperuricemia in relation to Perfluoroalkyl substances (PFASs) in children from Taiwan, 225 Taiwanese children aged 12–15 years were recruited from 2009 to 2010. Linear and logistic regression models were employed to examine the influence of PFASs on serum uric acid levels. Findings revealed that eight of ten PFASs analyses were detected in >94% of the participants' serum samples. Multivariate linear regression models revealed that perfluorooctanic acid (PFOA) was positively associated with serum uric acid levels (β = 0.1463, p < 0.05). Of all the PFASs analyses, only PFOA showed a significant effect on elevated levels of hyperuricemia (aOR = 2.16, 95%CI: 1.29–3.61). When stratified by gender, the association between serum PFOA and uric acid levels was only evident among boys (aOR = 2.76, 95%CI: 1.37–5.56). In conclusion, PFOA was found to be associated with elevated serum levels of uric acid in Taiwanese children, especially boys. Further research is needed to elucidate these links.
Mostrar más [+] Menos [-]Long-term impact of sewage sludge application on soil microbial biomass: An evaluation using meta-analysis Texto completo
2016
Charlton, Alex | Sakrabani, Ruben | Tyrrel, Sean | Rivas Casado, Monica | McGrath, Steve P. | Crooks, Bill | Cooper, Pat | Campbell, C. D. (Colin D.)
Long-term impact of sewage sludge application on soil microbial biomass: An evaluation using meta-analysis Texto completo
2016
Charlton, Alex | Sakrabani, Ruben | Tyrrel, Sean | Rivas Casado, Monica | McGrath, Steve P. | Crooks, Bill | Cooper, Pat | Campbell, C. D. (Colin D.)
The Long-Term Sludge Experiments (LTSE) began in 1994 as part of continuing research into the effects of sludge-borne heavy metals on soil fertility. The long-term effects of Zn, Cu, and Cd on soil microbial biomass carbon (Cmic) were monitored for 8 years (1997-2005) in sludge amended soils at nine UK field sites. To assess the statutory limits set by the UK Sludge (Use in Agriculture) Regulations the experimental data has been reviewed using the statistical methods of meta-analysis. Previous LTSE studies have focused predominantly on statistical significance rather than effect size, whereas meta-analysis focuses on the magnitude and direction of an effect, i.e. the practical significance, rather than its statistical significance. The results presented here show that significant decreases in Cmic have occurred in soils where the total concentrations of Zn and Cu fall below the current UK statutory limits. For soils receiving sewage sludge predominantly contaminated with Zn, decreases of approximately 7–11% were observed at concentrations below the UK statutory limit. The effect of Zn appeared to increase over time, with increasingly greater decreases in Cmic observed over a period of 8 years. This may be due to an interactive effect between Zn and confounding Cu contamination which has augmented the bioavailability of these metals over time. Similar decreases (7–12%) in Cmic were observed in soils receiving sewage sludge predominantly contaminated with Cu; however, Cmic appeared to show signs of recovery after a period of 6 years. Application of sewage sludge predominantly contaminated with Cd appeared to have no effect on Cmic at concentrations below the current UK statutory limit.
Mostrar más [+] Menos [-]Long-term impact of sewage sludge application on soil microbial biomass: An evaluation using meta-analysis Texto completo
2016
Charlton, Alex | Sakrabani, Ruben | Tyrrel, Sean F. | Rivas Casado, Monica | McGrath, Steve P. | Crooks, Bill | Cooper, Pat | Campbell, Colin D.
The Long-Term Sludge Experiments (LTSE) began in 1994 as part of continuing research into the effects of sludge-borne heavy metals on soil fertility. The long-term effects of Zn, Cu, and Cd on soil microbial biomass carbon (Cmic) were monitored for 8 years (1997-2005) in sludge amended soils at nine UK field sites. To assess the statutory limits set by the UK Sludge (Use in Agriculture) Regulations the experimental data has been reviewed using the statistical methods of meta-analysis. Previous LTSE studies have focused predominantly on statistical significance rather than effect size, whereas meta-analysis focuses on the magnitude and direction of an effect, i.e. the practical significance, rather than its statistical significance. The results presented here show that significant decreases in Cmic have occurred in soils where the total concentrations of Zn and Cu fall below the current UK statutory limits. For soils receiving sewage sludge predominantly contaminated with Zn, decreases of approximately 7–11% were observed at concentrations below the UK statutory limit. The effect of Zn appeared to increase over time, with increasingly greater decreases in Cmic observed over a period of 8 years. This may be due to an interactive effect between Zn and confounding Cu contamination which has augmented the bioavailability of these metals over time. Similar decreases (7–12%) in Cmic were observed in soils receiving sewage sludge predominantly contaminated with Cu; however, Cmic appeared to show of recovery after a period of 6 years. Application of sewage sludge predominantly contaminated with Cd appeared to have no effect on Cmic at concentrations below the current UK statutory limit.
Mostrar más [+] Menos [-]Insight into the adsorption of PPCPs by porous adsorbents: Effect of the properties of adsorbents and adsorbates Texto completo
2016
Zhu, Zengyin | Xie, Jiawen | Zhang, Mancheng | Zhou, Qing | Liu, Fuqiang
Adsorption is an efficient method for removal of pharmaceuticals and personal care products (PPCPs). Magnetic resins are efficient adsorbents for water treatment and exhibit potential for PPCP removal. In this study, the magnetic hypercrosslinked resin Q100 was used for adsorption of PPCPs. The adsorption behavior of this resin was compared with those of two activated carbons, namely, Norit and F400D. Norit exhibited the fastest adsorption kinetics, followed by Q100. Norit featured a honeycomb shape and long-range ordered pore channels, which facilitated the diffusion of PPCPs. Moreover, the large average pore size of Q100 reduced diffusion resistance. The adsorbed amounts of 11 PPCPs on the three adsorbents increased with increasing adsorbate hydrophobicity. For Q100, a significant linear correlation was observed between the adsorption performance for PPCPs and hydrophobicity (logD value) of adsorbates (R2 = 0.8951); as such, PPCPs with high logD values (>1.69) could be efficiently removed. Compared with those of Norit and F400D, the adsorption performance of Q100 was less affected by humic acid because of the dominant hydrophobic interaction. Furthermore, Q100 showed improved regeneration performance, which renders it promising for PPCP removal in practical applications.
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