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Short-term extractability of sulfadiazine after application to soils Full text
2013
Müller, Tanja | Rosendahl, Ingrid | Focks, Andreas | Siemens, Jan | Klasmeier, Jörg | Matthies, Michael
The long-term environmental fate of the veterinary antibiotic sulfadiazine (SDZ) in soils is determined by a reversible sequestration into a residual fraction and an irreversible formation of non-extractable residues (NER), which can be described as first-order rate processes. However, the concentration dynamics of the resulting fractions of SDZ in soil show an unexplained rapid reduction of extractability during the first 24 h. We therefore investigated the short-term extractability of SDZ in two different soils under different SDZ application procedures over 24 h: with and without manure, for air-dried and for moist soils. In all batches, we observed an instantaneous loss of extractability on a time scale of minutes as well as kinetically determined sequestration and NER formation over 24 h. Data evaluation with a simple kinetic model led to the conclusion that application with manure accelerated the short-term formation of NER, whereas sequestration was very similar for all batches.
Show more [+] Less [-]Application of compound-specific stable carbon isotope analysis for the biotransformation and trophic dynamics of PBDEs in a feeding study with fish Full text
2013
Luo, Xiao-Jun | Zeng, Yan-Hong | Chen, Hua-Shan | Wu, Jiang-Ping | Chen, She-Jun | Mai, Bi-Xian
The debromination and trophic dynamics of PBDEs in fish and whether or not compound-specific isotopic analysis (CSIA) can be used to trace these processes were investigated. Two predator/prey relationships were established in laboratory by two predatory fish species, oscar fish (OF) and redtail catfish (RF) feeding on tiger barb (TB) exposed to a commercial PBDE mixture. Metabolic debromination of PBDEs was observed in the TB and the OF, but not in the RF. The calculated biomagnification factors (BMFs) were uniform for most of the congeners in RF/TB but varied in OF/TB, which can be attributed to the metabolic debromination in the OF. The δ13C values of BDE47 and BDE28 were lower in fish than in those in the commercial mixture but the δ13C values of BDE99 were slightly higher. These results indicated that CSIA can be used to trace the biotransformation of PBDEs in biota.
Show more [+] Less [-]A review of metal (Pb and Zn) sensitive and pH tolerant bioassay organisms for risk screening of metal-contaminated acidic soils Full text
2013
Chapman, E.Emily V. | Dave, Göran | Murimboh, John D.
To improve risk estimates at the screening stage of Ecological Risk Assessment (ERA), short duration bioassays tailored to undisturbed soil cores from the contaminated site could be useful. However, existing standardized bioassays use disturbed soil samples and often pH sensitive organisms. This is a problem as naturally acidic soils are widespread. Changing soil properties to suit the test organism may change metal bioavailability, leading to erroneous risk estimates. For bioassays in undisturbed soil cores to be effective, species able to withstand natural soil properties must be identified. This review presents a critical examination of bioassay species' tolerance of acidic soils and sensitivity to metal contaminants such as Pb and Zn. Promising organisms include; Dendrobaena octaedra, Folsomia candida, Caenorhabditis elegans, Oppia nitens, Brassica rapa, Trifolium pratense, Allium cepa, Quercus rubra and Acer rubrum. The MetSTICK test and the Bait lamina test were also identified as suitable microorganism tests.
Show more [+] Less [-]Source contributions to carbonaceous species in PM2.5 and their uncertainty analysis at typical urban, peri-urban and background sites in southeast China Full text
2013
Niu, Zhenchuan | Wang, Sen | Chen, Jinsheng | Zhang, Fuwang | Chen, Xiaoqiu | He, Chi | Lin, Lifeng | Yin, Liqian | Xu, Lingling
Determination of 14C and levoglucosan can provide insights into the quantification of source contributions to carbonaceous aerosols, yet there is still uncertainty on the partitioning of organic carbon (OC) into biomass burning OC (OCbb) and biogenic emission OC (OCbio). Carbonaceous species, levoglucosan and 14C in PM2.5 were measured at three types of site in southeast China combined with Latin hypercube sampling, with the objectives to study source contributions to total carbon (TC) and their uncertainties, and to evaluate the influence of levoglucosan/OCbb ratios on OCbb and OCbio partitioning. It was found reliably that fossil fuel combustion is the main contributor (62.90–72.23%) to TC at urban and peri-urban sites. Biogenic emissions have important contribution (winter, 52.98%; summer, 45.71%) to TC at background site. With the increase in levoglucosan/OCbb ratios, the contribution of OCbio is increased while OCbb is decreased in a pattern of approximate natural logarithm at a given range.
Show more [+] Less [-]Distributions, sources and pollution status of 17 trace metal/metalloids in the street dust of a heavily industrialized city of central China Full text
2013
Li, Zhonggen | Feng, Xinbin | Li, Guanghui | Bi, Xiangyang | Zhu, Jianming | Qin, Haibo | Dai, Zhihui | Liu, Jinling | Li, Qiuhua | Sun, Guangyi
A series of representative street dust samples were collected from a heavily industrialized city, Zhuzhou, in central China, with the aim to investigate the spatial distribution and pollution status of 17 trace metal/metalloid elements. Concentrations of twelve elements (Pb, Zn, Cu, Cd, Hg, As, Sb, In, Bi, Tl, Ag and Ga) were distinctly amplified by atmospheric deposition resulting from a large scale Pb/Zn smelter located in the northwest fringe of the city, and followed a declining trend towards the city center. Three metals (W, Mo and Co) were enriched in samples very close to a hard alloy manufacturing plant, while Ni and Cr appeared to derive predominantly from natural sources. Other industries and traffic had neglectable effects on the accumulation of observed elements. Cd, In, Zn, Ag and Pb were the five metal/metalloids with highest pollution levels and the northwestern part of city is especially affected by heavy metal pollution.
Show more [+] Less [-]Diasteroisomer and enantiomer-specific profiles of hexabromocyclododecane and tetrabromobisphenol A in an aquatic environment in a highly industrialized area, South China: Vertical profile, phase partition, and bioaccumulation Full text
2013
He, Ming-Jing | Luo, Xiao-Jun | Yu, Le-Huan | Wu, Jiang-Ping | Chen, She-Jun | Mai, Bi-Xian
Tetrabromobisphenol A (TBBPA) and hexabromocyclododecanes (HBCDs) were determined in water, sediments, sediment cores, and three fish species from a river running through a highly industrialized area in South China. TBBPA concentrations exceeded those of HBCDs in the sediment and the dissolved phase of water and its levels in fish were at the high end of worldwide figures. 26% of HBCDs and 99% of TBBPA were found in dissolved phase of water. Plecostomus occupying high trophic level exhibited higher HBCD levels and higher abundance of α-HBCD than mud carp and nile tilapia which occupy low trophic level. An enrichment of (+)-α-HBCD in three fish species but (−)-α-HBCD in sediment was observed. As for γ-HBCD, most of sediment exhibited racemic while a species-dependence in fish sample was found. No clear trend was found for vertical distribution of enantiomeric profile for γ-HBCD, suggesting that the enantioselectivity of degradation of γ-HBCD is limited.
Show more [+] Less [-]Enhancing the biodegradation of oil in sandy sediments with choline: A naturally methylated nitrogen compound Full text
2013
Mortazavi, Behzad | Horel, Agota | Anders, Jennifer S. | Mirjafari, Arsalan | Beazley, Melanie J. | Sobecky, Patricia A.
We investigated how additions of choline, a naturally occurring methylated nitrogen-containing compound, accelerated hydrocarbon degradation in sandy sediments contaminated with moderately weathered crude oil (4000 mg kg−1 sediment). Addition of lauroylcholine chloride (LCC) and tricholine citrate (TCC) to oil contaminated sediments resulted in 1.6 times higher hydrocarbon degradation rates compared to treatments without added choline derivatives. However, the degradation rate constant for the oil contaminated sediments amended with LCC was similar to that in contaminated sediments amended with inorganic nitrogen, phosphorus, and glucose. Additions of LLC and TCC to sediments containing extensively weathered oil also resulted in enhanced mineralization rates. Cultivation-free 16S rRNA analysis revealed the presence of an extant microbial community with clones closely related to known hydrocarbon degraders from the Gammaproteobacteria, Alphaproteobacteria, and Firmicutes phyla. The results demonstrate that the addition of minimal amounts of organic compounds to oil contaminated sediments enhances the degradation of hydrocarbons.
Show more [+] Less [-]Placental IGF-1 and IGFBP-3 expression correlate with umbilical cord blood PAH and PBDE levels from prenatal exposure to electronic waste Full text
2013
Xu, Xijin | Yekeen, Taofeek Akangbe | Xiao, Qiongna | Wang, Yuangping | Lu, Fangfang | Huo, Xia
Electronic waste recycling produces Polycyclic Aromatic Hydrocarbons (PAHs) and Polybrominated Diphenyl Ethers (PBDEs) which may affect fetal growth and development by altering the insulin-like-growth factor (IGF) system. Questionnaires were administered to pregnant women (Guiyu, an e-waste site, n = 101; control, n = 53), and umbilical cord blood (UCB) and placentas were collected upon delivery. PBDEs and PAHs in UCB and placental IGF-1 and IGFBP-3 mRNA levels were analyzed using GC–MS and real-time PCR, respectively. Infant birth length and Apgar scores were lower in Guiyu. All PAHs (except Fl, Chr, IP, BbF and BP), total 16-PAHs, total/individual PBDEs, placental IGF-1 (median 0.23 vs 0.19; P < 0.05) and IGFBP-3 (median 1.91 vs 0.68; P < 0.001) levels were significantly higher in Guiyu. Spearman correlation showed that BDE-154, BDE-209 and ∑5ring-PAHs positively correlate with IGF-1 while PBDEs, 4 rings and total PAHs correlate with IGFBP-3 expression. Increased placental IGF-1 level might indirectly affect fetal growth and development.
Show more [+] Less [-]Measurement of humic-like substances in aerosols: A review Full text
2013
Zheng, Guangjie | He, Kebin | Duan, Fengkui | Cheng, Yuan | Ma, Yongliang
Aerosol-phase humic-like substances (HULIS) have received increasingly attention due to their universal ambient presence, active participation in atmospheric chemistry and important environmental and health effects. In last decade, intensive field works have promoted development of quantification and analysis method, unearthed spatio-temporal variation, and proved evidence for source identification of HULIS. These important developments were summarized in this review to provide a global perspective of HULIS. The diverse operational HULIS definitions were gradually focused onto several versions. Although found globally in Europe, Asia, Australasia and North America, HULIS are far more typical in continental and near-ground aerosols. HULIS concentrations varied from <1 μg/m3 to >13 μg/m3, with their carbon fraction making up 9%–72% of water soluble organic carbon. Dominant HULIS source was suggested as secondary processes and biomass burning, with the detailed formation pathways suggested and verified in laboratory works.
Show more [+] Less [-]Phytotoxicity and oxidative stress effect of 1-octyl-3-methylimidazolium chloride ionic liquid on rice seedlings Full text
2013
Liu, Huijun | Zhang, Shuxian | Hu, Xiaona | Chen, Caidong
The effects of the ionic liquid 1-octyl-3-methylimidazolium chloride ([OMIM]Cl) was studied in hydroponically grown rice seedlings. Observed effects included increased root length and weight at concentrations of 0.1 mg/L [OMIM]Cl, however, as concentrations increased a reversed response was observed where roots and stems grew shorter and the weight decreased. The inhibitory concentration 50 (IC50,5d) values for root length and stem length were 0.59 mg/L and 0.70 mg/L, respectively. The Hill reaction activity and root system activity in [OMIM]Cl-treated rice seedlings were observed to be lower than the controls, however, root membrane permeability increased. The antioxidant enzyme activity in roots decreased, while in leaves there was an initial stimulation followed by a decrease. Malondialdehyde (MDA) content was found to be greater in seedlings subjected to [OMIM]Cl treatment. The cellular structures, such as chloroplasts, mitochondria and rough endoplasmic reticulum in rice root and leaf cells were affected at concentrations of 0.6 mg/L [OMIM]Cl.
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