Refinar búsqueda
Resultados 2411-2420 de 3,208
Results of the clean-up operation to reduce pollution on flooded agricultural fields after the red mud spill in Hungary Texto completo
2015
Uzinger, Nikolett | Anton, Áron Dániel | Ötvös, Károly | Tamás, Péter | Anton, Attila
In Hungary, the dam of a red mud reservoir breached shortly after noon on October 4, 2010. Approximately 0.7–1 million m³ highly alkaline red mud with very low dry matter content flowed into the Torna Creek and the surrounding area, covering 1017 ha of agricultural land. Results of the risk assessment of the accident indicated that the red mud should be removed from the surface of fields where it formed a continuous layer of more than 5 cm. After the removal, samples were taken manually from depths of 0.0–0.2 m and 0.2–0.4 m in a sampling grid and background samples unaffected by red mud from the depth of 0.0–0.3 m. Total element contents (Ag, As, Ba, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sn, Zn, and Na) and pH values were measured, and the results were analysed using correlation analysis and the Kruskal–Wallis probe. Dependence of the measured variables from elevation above sea level was studied using a 10 m by 10 m digital elevation model. Only ∼6.5 % of the flooded area was temporarily designated as unsuitable for the production of food and fodder crops. In summary, the clean-up operation can be said to have been a success.
Mostrar más [+] Menos [-]Urinary arsenic, heavy metals, phthalates, pesticides, polyaromatic hydrocarbons but not parabens, polyfluorinated compounds are associated with self-rated health: USA NHANES, 2011–2012 Texto completo
2015
Shiue, Ivy
Links between environmental chemicals and human health have emerged, but the effects on self-rated health were less studied. Therefore, it was aimed to study the relationships of different sets of urinary environmental chemicals and the self-rated health in a national and population-based study in recent years. Data was retrieved from the US National Health and Nutrition Examination Surveys, 2011–2012, including demographics, serum measurements, lifestyle factors, self-rated health (with two grouping approaches) and urinary environmental chemical concentrations. T test and survey-weighted logistic regression modeling were performed. Among American adults aged 12–80 (n = 6833), 5892 people had reported their general health condition. Two thousand three hundred sixty-nine (40.2 %) people reported their general health condition as excellent or very good while 3523 (59.8 %) reported good, fair, or poor. People who reported their general health condition as good, fair, or poor had higher levels of urinary arsenic, heavy metals (including cadmium, cobalt, manganese, molybdenum, lead, antimony, strontium, tungsten and uranium), phthalates, pesticides and polyaromatic hydrocarbons but lower levels of benzophenone-3 and triclosan. There were no associations with urinary parabens, perchlorate, nitrate, thiocyanate or polyfluorinated compounds. However, only urinary cadmium, benzophenone-3, triclosan, and 2-hydroxynaphthalene remained significant when comparing between “good to excellent” and “poor to fair.” This is the first time observing risk associations of urinary arsenic, heavy metal, phthalate, pesticide, and hydrocarbon concentrations and self-rated health in people aged 12–80, although the causality cannot be established. Further elimination of these environmental chemicals in humans might need to be considered in health and environmental policies.
Mostrar más [+] Menos [-]Autotrophic perchlorate reduction kinetics of a microbial consortium using elemental sulfur as an electron donor Texto completo
2015
Gao, Mengchun | Wang, Sen | Jin, Chunji | She, Zonglian | Zhao, Congcong | Zhao, Yangguo | Zhang, Jian | Ren, Yun
The perchlorate reduction kinetic parameters of a microbial consortium using elemental sulfur (S⁰) as an electron donor were investigated in batch experiments. Standard Monod substrate utilization and biomass accumulation models were employed to fit the experimental data for microbial perchlorate reduction. The maximum observed yield coefficient for the microbial consortium was 0.19 mg dry weight (DW) mg⁻¹ ClO₄ ⁻, suggesting that the microbial consortium had a slow growth rate using S⁰ as the electron donor. The maximum specific substrate utilization rate (q ₘₐₓ) and half saturation constant (K ₛ) for microbial perchlorate reduction were 0.14 mg ClO₄ ⁻ mg⁻¹ DW day⁻¹ and 5.71 mg L⁻¹, respectively, which indicated that the microbial consortium could effectively utilize perchlorate as an electron acceptor. The variation of q ₘₐₓ with pH was described well by using a Gaussian peak equation, and the maximal value of q ₘₐₓ was obtained at pH 6.7. The presence of nitrate in perchlorate-contaminated water delayed the onset of sulfur autotrophic perchlorate reduction. The modified Gompertz equation could adequately describe the formation of Cl⁻ and SO₄ ²⁻ during the process of sulfur autotrophic perchlorate reduction. The SO₄ ²⁻ production exceeded the theoretical SO₄ ²⁻ production due to S⁰ disproportionation. The kinetic parameters for microbial perchlorate reduction are essential to design biological treatment systems, as well as to predict and evaluate their performance.
Mostrar más [+] Menos [-]Sorption-desorption behavior of pesticides and their degradation products in volcanic and nonvolcanic soils: interpretation of interactions through two-way principal component analysis Texto completo
2015
Báez, María E. | Espinoza, Jeannette | Silva, Ricardo | Fuentes, Edwar
Sorption-desorption behavior of six pesticides and some degradation products was assessed on seven agricultural volcanic and nonvolcanic soils belonging to Andisol, Ultisol, Mollisol, and Alfisol orders. The global interpretation of sorption data was performed by principal component analysis. Results showed exceptionally high sorption of glyphosate and aminomethylphosphonic acid (AMPA) (the breakdown product) on volcanic soils (K f > 1500 μg¹ ⁻ ¹ / ⁿ mL¹ / ⁿ g⁻¹) related mainly to contents of amorphous aluminum oxides (Andisols) and crystalline minerals (Ultisols). The lower sorption on nonvolcanic soils was associated to low organic matter contents and lack of significant minerals. Metsulfuron-methyl and 3,5,6-trichloro-2-pyridinol (metabolite of chlorpyrifos) were weakly to substantially sorbed on Andisols and Ultisols, but the first one was not sorbed at pH > 6.4, including nonvolcanic soils. The metabolite of diazinon, 2-isopropyl-4-methyl-6-hydroxypyrimidine, was weakly sorbed on all soils (K f = 0.4 to 3.6 μg¹ ⁻ ¹ / ⁿ mL¹ / ⁿ g⁻¹). Acidic compounds would be lixiviated in Mollisols and Alfisols, but they could leach also in Andisols and Ultisols if they reach greater depths. Atrazine and deethylatrazine sorption was related to organic carbon content; therefore, they were weakly retained on nonvolcanic soils (K f = 0.7 to 2.2 μg¹ ⁻ ¹ / ⁿ mL¹ / ⁿ g⁻¹). Chlorpyrifos was highly sorbed on all soils reaching K OC values of >8000. Finally, the significant retention of chlorothalonil and diazinon on Mollisols and Alfisols in spite of their low OC contents showed the contribution of clay minerals in the sorption process.
Mostrar más [+] Menos [-]Hydroacoustic and spatial analysis of sediment fluxes and accumulation rates in two Virginia reservoirs, USA Texto completo
2015
Clark, E. V. | Odhiambo, B. K. | Yoon, S. | Pilati, L.
Watershed sediment fluxes and reservoir sediment accumulation rates were analyzed in two contrasting reservoir systems in central and western Virginia. Lake Pelham, located in the Piedmont geologic province, is a human-impacted reservoir with a watershed dominated by agricultural, residential and industrial land uses. Conversely, Lake Moomaw has a largely undeveloped watershed characterized by very steep slopes and forested land use located in the Valley and Ridge province. The Revised Universal Soil Loss Equation (RUSLE) and sediment delivery ratios (SDRs) were used to estimate soil losses in the two watersheds. Bathymetric and sediment accumulation surveys of the two reservoirs were also conducted using a multi-frequency hydroacoustic surveying system. The RUSLE/SDR erosion model estimates 2150 kg ha⁻¹ year⁻¹ for Lake Pelham and 2720 kg ha⁻¹ year⁻¹ for Lake Moomaw, a 410 and 13 % increase from assumed pristine (100 % forested) land use for the respective basins. Mean sediment accumulation rates of 1.51 and 0.60 cm year⁻¹ were estimated from the hydroacoustic survey of Lake Pelham and Lake Moomaw, respectively. Overall, Lake Moomaw has relatively low sediment accumulation rates; however, the reservoir is vulnerable to increases in sediment fluxes with further human development due to the steep slopes and highly erodible colluvial soils that characterize the basin. Higher erosion and sediment accumulation rates in Lake Pelham are most likely reflecting the impact of human development on sedimentation processes, where the loss of vegetal buffers and increase in impervious surfaces exacerbates both the surficial soil losses as well as intrinsic stream sediment production leading to the current annual reservoir capacity loss of 0.4 %.
Mostrar más [+] Menos [-]Assessment of occurrence and concentrations of paraquat dichloride in water, sediments and fish from Warri River Basin, Niger Delta, Nigeria Texto completo
2015
Ikpesu, Thomas Ohwofasa
The distribution of Paraquat dichloride in different matrices of Warri River, Western Niger Delta, Nigeria was examined. The samplings and physicochemical parameters of the river were carried out during the dry and wet seasons, and stations were visited on monthly basis. The downstream stations had significant (p < 0.05) higher values than the control station. Seasonal variation revealed that, in water, the pesticide level was higher in the dry season than in wet season, and there was no significant difference between the seasons (p > 0.05). The reverse was the case for sediments and fish. The physicochemical parameters of the river’s water were within the recommended limits accepted by Federal Environmental Protection Agency, Nigeria. The observed Paraquat dichloride concentrations were above ecological bench, an observation that calls for regular monitoring and strict law enforcement to develop a strategy to manage environmental hazards and to improve environmental protection of this area.
Mostrar más [+] Menos [-]Influence of fermented tannery solid waste on morphological, biochemical, yield and nutritional responses of tomato plants Texto completo
2015
Ravindran, B. | Wong, J. W. C. | Celvam, Ā. | Murugesan, K. | Mohanapriya, D. | Sekaran, G.
The non-tanned proteinaceous tannery solid waste animal fleshing (ANFL), containing high nutritive value, was hydrolyzed using bacteria Selenomonas ruminantium HM000123 through submerged (SmF) and solid-state (SSF) fermentation processes. In addition, the effects of ANFL fermentative hydrolysate on growth, yield and biochemical properties of tomato plants were investigated. The treatments included T1 (SmF-ANFL), T2 (SSF-ANFL), T3 (recommended dose of NPK fertilizers) and a control without any amendment. Hydrolysates of both SmF-ANFL and SSF-ANFL treatments increased the biomass and yield as evidenced by plant height, stem girth, number of leaves and fruit yield when compared with both NPK and control plants. In this 90-day study, significant (p ≤ 0.05) changes were observed in SSF-ANFL treated plants compared to the other treatments. Protein profile analyzed through SDS-PAGE indicates the expression of a high molecular weight protein (205 kDa) and other proteins in the leaves of the SSF-ANFL treated plants. Overall results revealed that SSF-ANFL can be successfully utilized as a fertilizer particularly for cultivating tomato plants.
Mostrar más [+] Menos [-]The use of monitoring data in EU chemicals management—experiences and considerations from the German environmental specimen bank Texto completo
2015
Koschorreck, Jan | Heiss, Christiane | Wellmitz, Jörg | Fliedner, Annette | Rüdel, Heinz
Since the 1970s, environmental specimen banks (ESB) have emerged in many countries. Their highly standardised sampling and archiving strategies make them a valuable tool in tracing time trends and spatial distributions of chemicals in ecosystem compartments. The present article intends to highlight the potential of ESBs for regulatory agencies in the European Union (EU). The arguments are supported by examples of retrospective monitoring studies conducted under the programme of the German ESB. These studies have evaluated the success of regulatory and industry provisions for substances of concern (i.e. PCB, polybrominated diphenyl ethers, perfluorinated compounds, alkylphenol compounds, organotin compounds, triclosan/methyl-triclosan, musk fragrances). Time trend studies revealed for example that levels of organotin compounds in marine biota from German coastal waters decreased significantly after the EU had decided on a total ban of organotin-based antifoulings in 2003. Similarly, concentrations of commercially relevant congeners of polybrominated diphenyl ethers decreased in herring gull eggs from the North Sea only after an EU-wide ban in 2004. The data presented demonstrate the usefulness of ESB samples for (retrospective) time trend monitoring and underline the benefit of a more intensive cooperation between chemicals management and specimen banking.
Mostrar más [+] Menos [-]Relationship between variation of seasonal temperature and extent of occupational exposure to phthalates Texto completo
2015
Pilka, Tomas | Petrovicova, Ida | Kolena, Branislav | Zatko, Tomas | Trnovec, Tomas
Spot urine samples were collected in summer and winter season to examine the association between temperature variation and phthalate concentration in an occupationally exposed group. We analysed samples by high-performance liquid chromatography with mass spectrometry (HPLC-MS/MS) to determine the concentrations of four phthalate metabolites: mono (2-ethylhexyl) phthalate (MEHP), monobutyl phthalate (MnBP), monoethyl phthalate (MEP), and monoisononyl phthalate (MiNP). We observed significantly higher urinary concentrations of all monitored phthalate metabolites collected during the summer in occupationally exposed group (MEP p < 0.0015, MiNP p < 0.0001, MnBP p < 0.00019, and MEHP p < 0.05); however, in general, population was noticed this difference only for MEHP (p < 0.05) in winter season. We conclude that increasing indoor and outdoor temperature is related to phthalate exposure in specific types of work environment.
Mostrar más [+] Menos [-]An innovative coupling between column leaching and oxygen consumption tests to assess behavior of contaminated marine dredged sediments Texto completo
2015
Couvidat, Julien | Benzaazoua, Mostafa | Chatain, Vincent | Zhang, Fan | Bouzahzah, Hassan
Contaminated dredged sediments are often considered hazardous wastes, so they have to be adequately managed to avoid leaching of pollutants. The mobility of inorganic contaminants is a major concern. Metal sulfides (mainly framboïdal pyrite, copper, and zinc sulfides) have been investigated in this study as an important reactive metal-bearing phase sensitive to atmospheric oxygen action. An oxygen consumption test (OC-Test) has been adapted to assess the reactivity of dredged sediments when exposed to atmospheric oxygen. An experimental column set-up has been developed allowing the coupling between leaching and oxygen consumption test to investigate the reactivity of the sediment. This reactivity, which consisted of sulfide oxidation, was found to occur for saturation degree between 60 and 90 % and until the 20th testing week, through significant sulfates releases. These latter were assumed to come from sulfide oxidation in the first step of the test, then probably from gypsum dissolution. Confrontation results of OC-Test and leachate quality shows that Cu was well correlated to sulfates releases, which in turn, leads to Ca and Mg dissolution (buffer effect). Cu, and mostly Zn, was associated to organic matter, phyllosilicates, and other minerals through organo-clay complexes. This research confirmed that the OC-Test, originally developed for mine tailings, could be a useful tool in the dredged sediment field which can allow for intrinsic characterization of reactivity of a material suspected to readily reacting with oxygen and for better understanding of geochemical processes that affect pollutants behavior, conversion, and transfer in the environment.
Mostrar más [+] Menos [-]