Abstract：
:Use of maximum likelihood estimation procedures with multiple imputations to replace observations below the limit of detection (LOD) has been recommended. There is concern that the use of multiple imputations may introduce variability in the data resulting in different conclusions every time the same data are statistically analyzed. We analyzed data from National Health and Nutrition Examination Survey for 7 perfluorinated and 7 polybrominated diphenyl ethers to address these concerns. Data for each variable were subjected to 10 different iterations of statistical analysis. All observations below LOD were replaced by maximum likelihood estimation procedures with 5 imputations. The maximum variation in computing unadjusted geometric means over 10 iterations of analysis was about 2.5%. Unless the percent observations below LOD was more than 40%, maximum variation in computing adjusted geometric means was less than 1.5%. Maximum variation for computing adjusted geometric standard deviation was less than 6%. Except for border line comparisons, significance probabilities for pairwise comparisons did not vary enough to render contrasts from being statistically significant to statistically non-significant or vice versa. Similar conclusions applied to significance probabilities for regression slopes. The use of more than one multiply imputed variable in a regression model was not found to be of concern. The results show that the use of multiple imputations does not generate additional variabilities in the estimates of these statistics beyond tolerable statistical noise. However, when the percent observations in the data are relatively high, there is some possibility of obtaining disparate results.
journal_name
Chemospherejournal_title
Chemosphereauthors
Jain RBdoi
10.1016/j.chemosphere.2015.10.113subject
Has Abstractpub_date
2016-02-01 00:00:00pages
2044-51eissn
0045-6535issn
1879-1298pii
S0045-6535(15)30308-8journal_volume
144pub_type
杂志文章相关文献
CHEMOSPHERE文献大全abstract：:With the principal aim to assess the typical Mediterranean profile of the PM2.5 and PM1 pollution, three intensive monitoring campaigns took place simultaneously within different types of environment across an urban location of the basin. Focusing on the PM components with numerous anthropogenic sources and increased ...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2019.125026
更新日期：2020-02-01 00:00:00
abstract：:Aluminum salts are used as coagulants in water treatment; however, the exposure to residual aluminum has been associated with human brain lesions. The water-soluble Moringa oleifera lectin (WSMoL), which is extracted with distilled water and isolated by chitin chromatography, has coagulant activity and is able to redu...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2016.08.019
更新日期：2016-11-01 00:00:00
abstract：:Biogas slurry retention is a critical problem that cannot be solved by using the reuse method. Therefore, a new approach was taken to compensate for the shortcomings in the reuse method. In this study, after ammonia stripping, the ammonia nitrogen concentration in the stripped biogas slurry (SBS) still cannot reach th...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2020.129197
更新日期：2021-03-01 00:00:00
abstract：:Pyriproxyfen (PPF) is a larvicide, used to combat the proliferation of Aedes aegypti larvae. The objective of this study was to analyze the compounds of pyriproxyfen and pyridalyl (PYL) in a commercial larvicide to analyze the cytotoxic and oxidative effects of PPF and PYL. The toxic potential of PPF and PYL were asse...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2019.02.037
更新日期：2019-06-01 00:00:00
abstract：:Perfluorooctane sulfonate (PFOS), as one of emerging contaminants, has been attracting increasing concerns in recent years. Sorption of PFOS by maize straw- and willow-derived chars (M400 and W400), maize straw-origin ash (MA) as well as three carbon nanotubes (CNTs) was studied in this work. The sorption kinetics of ...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2011.04.018
更新日期：2011-05-01 00:00:00
abstract：:Mixing pesticides with different modes of action can provide a wider spectrum of control with fewer applications compared to using single active ingredients and is essential for comprehensive management of pest resistance. Mixture studies with pesticides are performed to assess compatibility, combined efficacy, and po...
journal_title：Chemosphere
pub_type： 杂志文章,评审
doi：10.1016/j.chemosphere.2018.06.081
更新日期：2018-10-01 00:00:00
abstract：:Antibiotics and pesticides may exist as a mixture in real environment. The combined effect of mixture can either be additive or non-additive (synergism and antagonism). However, no effective predictive approach exists on predicting the synergistic and antagonistic toxicities of mixtures. In this study, we developed a ...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2018.01.142
更新日期：2018-05-01 00:00:00
abstract：:Dissolved organic nitrogen (DON) is potential precursor of disinfection byproducts (DBPs), especially nitrogenous DBPs. In this study, we investigated the impact of biofilters on DON concentration changes in a drinking water plant. A small pilot plant was constructed next to a sedimentation tank in a drinking water pl...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2014.10.092
更新日期：2015-11-01 00:00:00
abstract：:Biomonitoring of exposure to polycyclic aromatic hydrocarbons (PAHs) typically uses measurement of metabolites of PAHs with four or less aromatic rings, such as 1-hydroxypyrene, even though interest may be in exposure to larger and carcinogenic PAHs, such as benzo[a]pyrene (B[a]P). An improved procedure for measuring ...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2017.09.077
更新日期：2017-12-01 00:00:00
abstract：:In many temperate regions, fuel and oil spills are sometimes managed simply by allowing natural degradation to occur, while monitoring soils and groundwater to ensure that there is no off-site migration or on-site impact. To critically assess whether this approach is suitable for coastal Antarctic sites, we investigat...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2005.07.040
更新日期：2006-03-01 00:00:00
abstract：:Among pharmaceuticals, the occurrence of antibiotics in the environment is a subject of special concern due to their environmental impact, namely the development of bacterial resistance. Sulfamethoxazole (SMX) is one of the most commonly used antibiotics and it is regularly found, not only in effluents from sewage tre...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2019.124613
更新日期：2020-01-01 00:00:00
abstract：:The fate of spinetoram was studied in a rice field ecosystem, and an efficient method for the determination of spinetoram (XDE-175-J and XDE-175-L) in soil, rice straw, paddy water, husk and brown rice was developed. Spinetoram residues were extracted from samples with a salting out extraction procedure. The extracts ...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2014.10.026
更新日期：2015-01-01 00:00:00
abstract：:The effects of water-saving patterns (Semi-dry water-saving, B; Shallow-wet control irrigation, Q; Traditional flooding irrigation, C; and Moistening irrigation, S) on the environmental fate of phenanthrene (Phe) and microbial responses in rhizosphere were investigated in paddy field system. Results showed the rice gr...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2020.128774
更新日期：2020-10-27 00:00:00
abstract：:The distribution of Cd, Cu, Pb and Zn between a contaminated soil and the tree species Paulownia tomentosa was investigated in a pilot-scale assisted phytoremediation study. The influence of the addition of EDTA, tartrate and glutamate at 1, 5 and 10mM concentrations on metal accumulation by the plant and on metal mob...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2008.04.083
更新日期：2008-08-01 00:00:00
abstract：:To investigate the occurrence and fate of ritalinic acid - the main human metabolite of the psychostimulant drug methylphenidate - in the aquatic environment, a HPLC-electrospray-MS/MS method for the quantification of ritalinic acid in wastewater, surface water and bank filtrate was developed. Carbamazepine known as v...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2010.09.018
更新日期：2010-12-01 00:00:00
abstract：:The levels of polychlorinated dibenzo-dioxins (PCDDs), polychlorinated dibenzo-furans (PCDFs), coplanar polychlorinated biphenyls (coPCBs), and polybrominated diphenyl ethers (PBDEs) were measured in fish collected from San Francisco Bay in 2000 and from the California coast in 2001. The samples were composites of onl...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2005.12.012
更新日期：2006-06-01 00:00:00
abstract：:This work investigated the effect of variably formulated pesta granules containing wild and UV mutated Pseudomonas aeruginosa and Lasiodiplodia pseudotheobromae on the rate of CO2 evolution, organic carbon content, enzymatic activity (acidic and alkaline phosphatase, dehydrogenases, urease and protease) and representa...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2017.12.056
更新日期：2018-03-01 00:00:00
abstract：:This study experimentally demonstrated that polyphosphate accumulating organisms (PAOs) losing the abilities of anaerobically synthesizing polyhydroxyalkanoates and aerobically taking up phosphate under Cu(II) presence was due to the inhibition of enzyme activities of acetyl-CoA synthases (ACS) and polyphosphate kinas...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2012.11.080
更新日期：2013-04-01 00:00:00
abstract：:High levels of p,p'-DDT were detected in Hong Kong breast milk sampled in 1976 and 1985. Monitoring DDT levels in human breast milk in this region is important to identify trends in exposure. As part of the 2002-03 WHO/EURO coordinated exposure study, the concentrations of DDT and its metabolites were determined in 10...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2008.05.045
更新日期：2008-08-01 00:00:00
abstract：:Na-A zeolite (Z-S1) was synthesized from scoria found on Jeju Island, Korea using the fusion/hydrothermal method. The influences of NaOH/scoria ratio, SiO2/Al2O3 molar ratio, and particle sizes on the synthesis of zeolite were studied by analyzing crystals morphology and crystallinity. According to XRD analysis, it wa...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2018.05.080
更新日期：2018-09-01 00:00:00
abstract：:The distribution and seasonal variation of fifteen antibiotics belonging to three classes (sulfonamides, fluoroquinolones and tetracyclines) were investigated in Lake Chaohu, China. The concentrations of the selected antibiotics in the surface water, eight major inflowing rivers and sewage treatment plant (STP) sample...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2014.11.032
更新日期：2015-03-01 00:00:00
abstract：:Recycling of industrial wastewater meeting quality standards for agricultural and industrial demands is a viable option. In this study, paper and pulp industrial wastewater were treated with three biological treatments viz. aerobic, anaerobic and sequential (i.e. 20 days of anaerobic followed by 20 days of aerobic cyc...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2019.04.022
更新日期：2019-07-01 00:00:00
abstract：:A single microwave extraction procedure was conducted to investigate the bioavailability of rare earth elements (REEs) by using different extractants of 0.05 M EDTA, 0.10 M CH3COOH, 0.10 M HCl, and 0.05 M CaCl2. The experimental conditions of heating time and microwave power were optimized. A microwave power of 60% an...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/S0045-6535(03)00672-6
更新日期：2003-12-01 00:00:00
abstract：:Sediments dredged by an industrial port, slightly contaminated by heavy metals and petroleoum hydrocarbons, were phytoremediated and used as peat-free growing media for the red robin photinia (Photinia x fraseri L.). Plants were grown on sediment only (S), sediment mixed with composted pruning residues (S + PR), sedim...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2018.02.172
更新日期：2018-06-01 00:00:00
abstract：:The formation potential of carbonaceous and nitrogenous disinfection by-products (C-DBPs, N-DBPs) after ion exchange treatment (IEX) of three different water types in multiple consecutive loading cycles was investigated. Liquid chromatography with organic carbon detector (LC-OCD) was employed to gauge the impact of IE...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2015.10.086
更新日期：2016-02-01 00:00:00
abstract：:Toxaphene is a pesticide whose use was banned in North America because of concerns regarding its toxicity. To obtain better data on the metabolism and toxicity of toxaphene in primates, a one year feeding study was carried out in cynomologous monkeys at a dose of 1 mg/kg/day for one year. Levels of toxaphene residues ...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/0045-6535(96)00024-0
更新日期：1996-03-01 00:00:00
abstract：:In this work, the photocatalytic degradation of aqueous microcystin-LR was studied using TiO(2) and ZnO as photocatalysts. The process was optimised and characterised at the bench scale (200 mL); both semiconductors exhibited a high degradation capacity at reaction times of 1 min (degradation greater than 95%). The tr...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2012.09.004
更新日期：2013-01-01 00:00:00
abstract：:The degradation intermediates of phenanthrene (PHE) may have increased health risks to organisms than PHE. Therefore, environmental fate and risk assessment studies should take into considerations of PHE degradation products. This study compared the sorption properties of PHE and its degradation intermediates, 9,10-ph...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2011.10.010
更新日期：2012-01-01 00:00:00
abstract：:The metal emissions from three incinerators burning different feedstock in Taiwan were characterized in this study. It was found that the Incinerators A and B, treating pig carcasses and animal (including pigs) carcasses, respectively, had much higher metal concentrations in stack flue gases than Incinerator C that co...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2003.12.020
更新日期：2004-06-01 00:00:00
abstract：:The role of microplastics (MPs) as a carrier of pollutants in water environment is an emerging issue; however, information regarding the underlying mechanisms for malachite green (MG) and Pb(II) adsorption onto hexabromocyclododecane (HBCD)-polystyrene (PS) composites MPs (HBCD-PS MPs) is still lacking. In this study,...
journal_title：Chemosphere
pub_type： 杂志文章
doi：10.1016/j.chemosphere.2020.129079
更新日期：2021-02-01 00:00:00
