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841.
Environmental Science and Pollution Research - In city playgrounds, there is a potential risk of harming children’s health by contamination coming from anthropogenic activities. With the aim...  相似文献   
842.
Abstract

Activated carbons are well-known porous materials as an effective adsorbent used for the removal of emerging contaminants, such as herbicides, which are increasingly present in water bodies. Most water treatment plants, specially in Brazil, are unable to completely remove such contaminants by the conventional process and advanced treatment using activated carbons is required. The aim of this paper was to verify the influence of the activated carbons granulometry and specific surface area on the 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide removal efficiency using distilled-deionized water and filtered water collected from a conventional Water Treatment Plant. Commercial activated carbons samples used in this work were obtained from two different manufacturers. Activated carbons were analyzed by the specific surface area, pore size and volume distribution, nuclear magnetic resonance, infrared and x-ray spectroscopy, moisture, volatile matter and ash contents. Batch adsorption isotherms experiments were used and performed by Langmuir and Freundlich models. Granular and powdered activated carbons removed over 99% of 2,4-D in distilled water and near to 99% using filtered water. The activated carbons evaluated in this work presented high performance and played a key role in water treatment by removing 2,4-D herbicide, ensuring the protection of human health and the ecosystem.  相似文献   
843.
Abstract

Glyphosate is the main herbicide currently used in the world due to wide applicability and efficiency in controlling weeds in many crops. However, its overuse may lead to undesirable impacts on the environment and to human health in the long run. This present study aimed to optimize and validate solid phase extraction (SPE) using an anionic resin for the simultaneous and direct determination of glyphosate and aminomethylphosphonic acid (AMPA) in water samples using high-performance liquid chromatography combined with inductively coupled plasma with triple quadrupole mass spectrometer (HPLC-ICP-MS/MS). The results showed that recovery percentage and relative standard deviation were 103.9?±?7.9 and 99.40?±?9.9% for glyphosate and AMPA, respectively. The validation certified that the method was precise, accurate, linear, and selective, with a limit of quantification of 1.09 and 0.29?μg L?1 for glyphosate and AMPA, respectively. The optimized methodology reached the concentration factor of 250 times and was successfully applied to analyze water samples from hydroponic cultivation of the eucalyptus seedlings. The results showed that the exudation process occurs at glyphosate doses starting from 2?L ha?1.  相似文献   
844.
A study was conducted in the southeastern region of Buenos Aires province, Argentina, to assess an agricultural soil as a potential source of organochlorine (OC) pesticides for the aquatic biota of a nearby pond. We analyzed gamma-HCH (lindane), still in use, and the following banned compounds: DDT, DDE, DDD heptachlor, heptachlor epoxide, aldrin, dieldrin and endrin in soil, bulrush, grass shrimp and fish using gas chromatography with electron capture detection (GC-ECD). Among the OC pesticides, lindane was most dominant in the soil (32.6 ng/g dry wt in the upper and 173.9 ng/g dry wt in the lower horizon) and bulrush (1.9 pg/g lipid). Macrophyte also accumulated high levels of heptachlor epoxide (1.5 pg/g lipid). Heptachlor, although present in the soil, was below the detection limit in all aquatic biota studied. Its primary degradation product, heptachlor epoxide, was found in both soil and biota samples. DDT was found at low levels in the surface soil (6.8 ng/g dry wt), but at higher concentrations in fish (3.6 pg/g lipid), although levels were still below permissible levels for human consumption. Since most of the compounds were found in both soil and aquatic biota, our study suggests that agricultural soil could be an important source for OC pesticides in the nearby pond.  相似文献   
845.
The ethoxy resorufin dealkylase (EROD) inducing potency of 10 polycyclic aromatic hydrocarbons (PAHs) is measured in the H4IIE in vitro bioassay and the results are compared to those reported in literature. The selected PAHs varied considerably in their potency to induce EROD activity. Anthracene (Ant) and phenanthrene (Phe) showed consistently no response. Naphthalene (Nap) showed no or a very weak response on EROD activity. Fluoranthene (Fla) and benzo[g,h,i]perylene (BghiP) showed weak responses at the highest doses. The other PAHs, including indeno[1,2,3-cd]pyrene (IP), benz[a]anthracene (BaA), benzo[a]pyrene (BaP), chrysene (Chr) and benzo[k]fluoranthene (BkF), showed full bell shaped dose-response curves. BaP EROD induction equivalency factors (BaP-1EF) were calculated and increased in the order Ant approximately Phe < Fla < Nap < BghiP < IP < BaA < BaP < Chr < BkF. Comparison of BaP-IEFs based on 50% effect concentration (EC50) or lowest effect concentration (LEC), yielded a significant relationship between both methods described by the equation log(BaPIEF(EC50) = 0.55 x log(BaPIEF(LEC)) + 0.07 (r2 = 0.913). BaP-IEFs as derived from our measurements and as reported in literature and measured in other in vitro assays deviated up to a factor of 17 among the different studies, but the potency rankings were comparable. For the PAH mixture as on average present in the human diet an overall tetrachlorodibenzo-p-dioxin (TCDD)-IEF of 1 x 10(-4) was estimated. The total PAH based TCDD induction equivalents (IEQ) intake then was calculated 300 pg/day, which is approximately 2 times higher then the PHAH based TCDD-EQ intake reported for humans.  相似文献   
846.
Microbial displacement in the soil is an important process for bioremediation and dispersal of wastewater pathogens. We evaluated cell movement in surface and subsurface red-yellow podzolic soil driven by advection and microbial motility and also survival of a microbial population at high pressure as is prevalent in deep soil layers. Pseudomonas fluorescens Br 12, resistant to rifampycin and kanamycin, was used as a model organism traceable in non-sterile soil. Our results showed that more than 40% of the P. fluorescens population survived under high pressure, and that microbial motility was not a major factor for its displacement in the soil. Cells were adsorbed in similar amounts to surface and subsurface soils, but more viable cells were present in the leachate of surface than in subsurface soils. The nature of this unexpected cell binding to the subsurface soil was studied by EPR, Mossbauer, NMR, and infrared techniques, suggesting iron had a weak interaction with microbes in soil. P. fluorescens movement in soil resulted mainly from convection forces rather than microbial motility. The transport of this bacterium along the transept toward groundwater encountered restricted viability, although it survived under high pressure conditions simulating those in deep soil layers.  相似文献   
847.
Levels and trends of brominated flame retardants in the Arctic   总被引:24,自引:0,他引:24  
de Wit CA  Alaee M  Muir DC 《Chemosphere》2006,64(2):209-233
Polybrominated diphenyl ethers (PBDEs) containing two to seven bromines are ubiquitous in Arctic biotic and abiotic samples (from zooplankton to polar bears (Ursus maritimus) and humans; air, soil, sediments). The fully brominated decabromodiphenyl ether (BDE-209), hexabromocyclododecane (HBCD), tetrabromobisphenol A (TBBPA) and polybrominated biphenyls (PBBs) are also present in biotic and abiotic samples. Spatial trends of PBDEs and HBCD in top predators are similar to those seen for polychlorinated biphenyls (PCBs) and indicate western Europe and eastern North America as source regions. Concentrations of tetra- to heptaBDEs have increased significantly in North American and Greenlandic Arctic biota and in Greenland freshwater sediments paralleling trends seen further south. For BDE-209, increasing concentrations in Greenlandic peregrine falcons (Falco peregrinus) and in dated lake sediment cores in the Canadian Arctic have been seen during the 1990s. BDE-47, -99, -100 and -153 are observed to biomagnify in Arctic food webs. summation operatorPBDE concentrations in Arctic samples are lower than in similar sample types from more southerly regions and are one or more orders of magnitude lower than summation operatorPCB concentrations except for some levels for air. Air and harbor sediment results for PBDEs indicate that there are local sources near highly populated areas within the Arctic. Findings of PBBs on moss and TBBPA on an air filter, and that both are found in biota at high trophic levels indicates that these compounds may also reach the Arctic by long-range atmospheric transport. Based on the evidence of their presence in the Arctic and indications that most if not all are undergoing long-range transport, these brominated flame retardants (BFRs) have characteristics that qualify them as POPs according to the Stockholm Convention.  相似文献   
848.
Environmental Science and Pollution Research - Indoor air pollution is an important risk factor for the generation of lung diseases in developing countries. The indigenous population is...  相似文献   
849.
The efficiency of a water treatment program or a water monitoring program can be checked only if it is accompanied by water analysis procedures allowing meaningful statements on water quality. Meaningful statements do not only include high accuracy, but high precision as well. With high precision values, good repeatability and reproducibility is aimed for. Repeatability and reproducibility may either be monitored by regular inter-laboratory trials, without prescribing a distinct analytical method, or by applying a standardized method which has undergone thorough checks concerning its reliability and efficiency. The article presents the structure of the ISO, CEN and DIN standardization work in water analysis.  相似文献   
850.
The impact on plant growth of the simultaneously changing factors of the global climate, rising tropospheric O3 concentrations and increasing UV-B radiation fluxes, has been tested in a combined glasshouse and growth chamber experiment. The saltmarsh grass species Elymus athericus was sequentially fumigated for two weeks with O3 and for another two weeks irradiated with UV-B (vv). Exposure to elevated UV-B did not negatively affect photosynthesis or plant growth. Fumigation with O3 had a depressing effect on net photosynthesis, the number and biomass of flowers, the number of leaves and the number of shoots. O3-induced damage only was observed in plants which had been fumigated during the last two weeks of the experiment. Since interactive responses were not observed, results suggest different primary target sites for O3 and UV-B within the plant.  相似文献   
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