Method of median semi-variance for the analysis of left-censored data: Comparison with other techniques using environmental data

Zoffoli, Hugo José Oliveira; Varella, Carlos Alberto Alves; Sobrinho, Nelson Moura Brasil do Amaral; Zonta, Everaldo; Tolón‐Becerra, Alfredo

doi:10.1016/j.chemosphere.2013.05.041

Cited by 15 publications

(8 citation statements)

References 33 publications

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“…Some nestlings (16%) had blood Pb concentrations below the limit of detection, and we used the method of median semi‐variance (SemiV) to estimate values for the left‐censored data as described by Zoffoli et al. (). The SemiV approach to handling left‐censored data minimizes the bias in associated error for the mean and standard deviation (Zoffoli et al.…”

Section: Methodsmentioning

confidence: 99%

“…The SemiV approach to handling left‐censored data minimizes the bias in associated error for the mean and standard deviation (Zoffoli et al. ) and is not flawed like traditional substitution and deletion methods that have no statistical underpinning (Helsel , Zoffoli et al. ).…”

Section: Methodsmentioning

confidence: 99%

“…) and is not flawed like traditional substitution and deletion methods that have no statistical underpinning (Helsel , Zoffoli et al. ). We present blood Pb concentrations as μg/g (parts per million; ppm) wet weight.…”

Section: Methodsmentioning

confidence: 99%

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The lead (Pb) lining of agriculture‐related subsidies: enhanced Golden Eagle growth rates tempered by Pb exposure

et al. 2020

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2020. The lead (Pb) lining of agriculture-related subsidies:enhanced Golden Eagle growth rates tempered by Pb exposure. Ecosphere 11(1):Abstract. Supplementary food resources (e.g., subsidies) associated with agriculture can benefit wildlife species, increasing predictability and availability of food. Avian scavengers including raptors often utilize subsidies associated with both recreational hunting and pest shooting on agricultural lands. However, these subsidies can contain lead (Pb) fragments if they are culled with Pb-based ammunition, potentially leading to Pb poisoning and physiological impairment in wildlife. Nesting Golden Eagles (Aquila chrysaetos) commonly forage in agricultural lands during the breeding season, and therefore, both adults and their nestlings are susceptible to Pb exposure from scavenging shot wildlife. We assessed drivers of Pb exposure in 258 nestling Golden Eagles (401 total blood samples), along with physiological and growth responses, in agricultural lands across four western states in the United States. We also evaluated the birds' Pb stable isotope signatures to inform exposure sources. Twenty-six percent of Golden Eagle nestlings contained Pb concentrations associated with subclinical poisoning for sensitive species (0.03-0.2 lg/g ww), 4% had Pb concentrations that exceeded subclinical poisoning benchmarks (0.2-0.5 lg/g ww), and <1% exceeded either concentrations associated with clinical poisoning (0.5-1.0 lg/g ww) and or those deemed to cause severe clinical poisoning (>1.0 lg/g ww). Lead concentrations were highest in nestlings with close proximity to fields that potentially provided subsidies and declined exponentially as distance to subsidies increased. However, close proximity to agriculture, and presumably subsidies, positively influenced nestling growth rates. Across the range of Pb exposure, nestlings experienced a 67% reduction in delta-aminolevulinic acid dehydratase (d-ALAD) activity, suggesting nestlings may have been anemic or experiencing cellular damage. Isotopic ratios of 206 Pb/ 207 Pb increased non-linearly with increasing blood Pb in Golden Eagle nestlings, and 45% of the birds were consistent with those of ammunition. However, above 0.10 lg/g ww, the proportion associated with ammunition increased to 89% of the nestlings. An improved understanding of how these positive (growth) and negative (physiology) effects associated with proximity to subsidies interact would be beneficial to managers when considering management scenarios and potentially evaluating any measures taken to reduce Pb exposure across the landscape.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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The lead (Pb) lining of agriculture‐related subsidies: enhanced Golden Eagle growth rates tempered by Pb exposure

et al. 2020

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“…For statistical analysis of these data, deletion (ignoring the observations) or substitution with zero methods provide a biased performance. Therefore, in order to minimize this bias, non-detected and non-quantified data were substituted for a fixed value: LOQ divided by the square root of two (LOQ/√2) [27].…”

Section: Methodsmentioning

confidence: 99%

Overexposure to Bisphenol A and Its Chlorinated Derivatives of Patients with End-Stage Renal Disease during Online Hemodiafiltration

et al. 2019

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The health safety conditions governing the practice of online hemodiafiltration (OL-HDF) do not yet incorporate the risks related to the presence of endocrine disruptors such as bisphenol A (BPA). The aim of this study was to assess, for the first time, the exposure to BPA but also to its chlorinated derivatives (ClxBPA) (100 times more estrogenic than BPA) during OL-HDF. We demonstrated that BPA is transmitted by the different medical devices used in OL-HDF: ultrafilters, dialysis concentrate cartridges (and not only dialyzers, as previously described). Moreover, BPA has been found in dialysis water as well as in ultrapure dialysate and replacement fluid due to contamination of water coming from municipal network. Indeed, due to contaminations provided by both ultrafilters and water, high levels of BPA were determined in the infused replacement fluid (1033 ng.L−1) from the beginning of the session. Thus, our results demonstrate that dialysis water must be considered as an important exposure source to endocrine disruptors, especially since other micropollutants such as ClxBPA have also been detected in dialysis fluids. While assessment of the impact of this exposure remains to be done, these new findings should be taken into account to assess exposure risks in end-stage renal disease patients.

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“…This has been recommended when relatively few data are below the detection limit or where data are not highly skewed [35]. Therefore, this procedure has been widely used because of its simplicity and ease of operation and produce low bias and moderate precision using environmental data [36]. Lipid-normalized values (ng/g lipid) for BDE-47 were used in the analysis.…”

Section: Methodsmentioning

confidence: 99%

Genetic variation in the CYP2B6 Gene is related to circulating 2,2’,4,4’-tetrabromodiphenyl ether (BDE-47) concentrations: an observational population-based study

et al. 2014

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BackgroundSince human CYP2B6 has been identified as the major CYP enzyme involved in the metabolism of 2,2’,4,4’-tetrabromodiphenyl ether (BDE-47) and that human 2B6 is a highly polymorphic CYP, with known functional variants, we evaluated if circulating concentrations of a major brominated flame retardant, BDE-47, were related to genetic variation in the CYP2B6 gene in a population sample.MethodsIn the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (men and women all aged 70), 25 single nucleotide polymorphisms (SNPs) in the CYP2B6 gene were genotyped. Circulating concentrations of BDE-47 were analyzed by high-resolution gas chromatography coupled to high-resolution mass spectrometry (HRGC/ HRMS).ResultsSeveral SNPs in the CYP2B6 gene were associated with circulating concentrations of BDE-47 (P = 10-4 to 10-9). The investigated SNPs came primarily from two haplotypes, although the correlation between the haplotypes was rather high. Conditional analyses adjusting for the SNP with the strongest association with the exposure (rs2014141) did not provide evidence for independent signals.ConclusionCirculating concentrations of BDE-47 were related to genetic variation in the CYP2B6 gene in an elderly population.

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Method of median semi-variance for the analysis of left-censored data: Comparison with other techniques using environmental data

Cited by 15 publications

References 33 publications

The lead (Pb) lining of agriculture‐related subsidies: enhanced Golden Eagle growth rates tempered by Pb exposure

The lead (Pb) lining of agriculture‐related subsidies: enhanced Golden Eagle growth rates tempered by Pb exposure

Overexposure to Bisphenol A and Its Chlorinated Derivatives of Patients with End-Stage Renal Disease during Online Hemodiafiltration

Genetic variation in the CYP2B6 Gene is related to circulating 2,2’,4,4’-tetrabromodiphenyl ether (BDE-47) concentrations: an observational population-based study

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