Regional-scale mapping for determining geochemical background values in soils of the Itacaiúnas River Basin, Brazil: The use of compositional data analysis (CoDA)

Sahoo, Prafulla Kumar; Dall’Agnol, Roberto; Salomão, Gabriel Negreiros; Ferreira, Jair da Silva; Silva, Marcio Sousa; Souza-Filho, Pedro Walfir M.; Costa, Marcondes Lima da; Angélica, Rômulo Simões; Filho, Carlos Augusto Medeiros; Costa, Marlene Furtado da; Guilherme, Luiz Roberto Guimarães; Siqueira, José Oswaldo

doi:10.1016/j.geoderma.2020.114504

Cited by 44 publications

(33 citation statements)

References 76 publications

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“…Before statistical treatment, zero values (which supposedly occurred during instrument calibration) were stripped from the datasets. Statistical treatments included descriptive statistics such as minimum, maximum and mean ± standard deviation (SD) and multivariate analysis such as Spearman correlation matrix (visualized in heat-plots) and principal component analysis (PCA)], carried out following standard methods (Reimann et al 2018 ; Sahoo et al 2020b ). The COVID-19 baseline threshold (CBT) levels (i.e., the upper limit of COVID-19 baseline variation) were calculated using a percentile-based approach (75th, 95th, 98th), median + 2 median absolute deviation (mMAD), mean + 2 standard deviation (SD), Tukey inner fence (TIF; 3rd quartile + 1.5* interquartile range) and cumulative frequency distribution using log-transformed data (Reimann et al 2018 ; Salõmao et al 2019 ; Sahoo et al 2020b ).…”

Section: Methodsmentioning

confidence: 99%

“…The upper limit of baseline variation is known as threshold value. In this study, the COVID-19 baseline threshold values (CBT; upper limit) were estimated using the recently developed statistical technique such as mMAD, TIF and percentiles, which are commonly used in geochemical studies (Sahoo et al 2020b ; Salãmao et al 2019 ). Table 2 presents the CBT values for air quality parameters in Delhi by different methods.…”

Section: Methodsmentioning

confidence: 99%

“…TIF is a good method, but it sometimes exceeds the maximum concentration, as shown in Table 2 . This may depend on data distribution that does not indicate the presence of outliers (Reimann et al, 2018 ; Sahoo et al 2020b ); thus, this technique may not be suitable. mMAD, which is more robust and relies on the median and the median absolute deviation (MAD) of the data distribution and is inherently stable against outliers and deviations, may be more suitable (Salomão et al 2019 ; Reimann et al 2018 ).…”

Section: Methodsmentioning

confidence: 99%

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COVID-19 lockdown: a rare opportunity to establish baseline pollution level of air pollutants in a megacity, India

Sahoo

Salomão

Júnior

et al. 2021

Int. J. Environ. Sci. Technol.

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This paper analyses air quality data from megacity Delhi, India, during different periods related to the COVID-19, including pre-lockdown, lockdown and unlocked (post-lockdown) (2018–2020) to determine what baseline levels of air pollutants might be and the level of impact that could be anticipated under the COVID-19 lockdown emission scenario. The results show that air quality improved significantly during the lockdown phases, with the most significant changes occurring in the transportation and industrially dominated areas. A pronounced decline in PM 2.5 and PM 10 up to 63% and 58%, respectively, was observed during the lockdown compared to the pre-lockdown period in 2020. When compared to 2018 and 2019, they were lower by up to 51% and 61%, respectively, dropping by 56% during unlock. Some pollutants (NOx and CO) dropped significantly during lockdown, while SO 2 and O 3 declined only slightly. Moreover, when compared between the different phases of lockdown, the maximum decline for most of the pollutants and air quality index occurred during the lockdown phase 1; thus, this period was used to report the COVID-19 baseline threshold values (CBT; threshold value is the upper limit of baseline variation). Of the various statistical methods used median + 2 median absolute deviation (mMAD) was most suitable, indicating CBT values of 143 and 75 ug/m 3 for PM 10 and PM 2.5 , respectively. This results although preliminary, but it gives a positive indication that temporary lockdown can be considered as a boon to mitigate the damage we have done to the environment. Also, this baseline levels can be helpful as a first line of information to set future target limits or to develop effiective management policies for achieving better air quality in urban centres like Delhi. Supplementary Information The online version contains supplementary material available at 10.1007/s13762-021-03142-3.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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COVID-19 lockdown: a rare opportunity to establish baseline pollution level of air pollutants in a megacity, India

Sahoo

Salomão

Júnior

et al. 2021

Int. J. Environ. Sci. Technol.

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“…Determination of GBV has been an important issue 16 , 17 . However, development of GBV is not straightforward as there is no single standard or recommended methodology 18 . Kicińska and Turek 19 stated that three group of methods are widely used for establishing the GBV: direct, indirect and integrated methods.…”

Section: Introductionmentioning

confidence: 99%

“…The most commonly used worldwide are the relative cumulative distribution function method and regression analysis method 16 , 23 . Sahoo et al 18 suggested that the cumulative frequency distribution plots can be used as an alternative method to define GBV by analysing points of inflection in the curve, but it is more subjective than the mMAD and TIF methods. The integrated method is a combination of direct and indirect methods.…”

Section: Introductionmentioning

confidence: 99%

Causes of variations of trace and rare earth elements concentration in lakes bottom sediments in the Bory Tucholskie National Park, Poland

Sojka

Choiński

Ptak

et al. 2021

Sci Rep

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The objective of this study was to analyse spatial variability of the trace elements (TEs) and rare earth elements (REEs) concentration in lake bottom sediments in Bory Tucholskie National Park (BTNP); Poland. The following research questions were posed: which factors have a fundamental impact on the concentration and spatial variability of elements in bottom sediments, which of the elements can be considered as indicators of natural processes and which are related to anthropogenic sources. The research material was sediments samples collected from 19 lakes. The concentrations of 24 TEs and 14 REEs were determined. The analyses were carried out using the inductively coupled plasma mass spectrometry (ICP-QQQ). Cluster analysis and principal component analysis were used to determine the spatial variability of the TEs and REEs concentrations, indicate the elements that are the indicators of natural processes and identify potential anthropogenic sources of pollution. The geochemical background value (GBV) calculations were made using 13 different statistical methods. However, the contamination of bottom sediments was evaluated by means of the index of geo-accumulation, the enrichment factor, the pollution load index, and the metal pollution index. The BTNP area is unique because of its isolation from the inflow of pollutants from anthropogenic sources and a very stable land use structure over the last 200 years. This study shows high variability of TE and REE concentrations in lake sediments. The values of geochemical indices suggest low pollution of lakes bottom sediments. It was found that TEs originated mainly from geogenic sources. However, the concentrations of Li, Ni, Sc, Se, Be, Se, Ag, Re, Tl, Cd, Sb and U may be related to the impact of point sources found mainly in the Ostrowite Lake. Almost all REEs concentrations were strongly correlated and their presence was linked to with geochemical processes. The elements allowing to identify natural processes and anthropogenic pollution sources were Cr, Co, Cu, Ag, Cd, Zn, Bi, Re, Ba, Al and Rb in TEs group and Nd, Gd, Yb, Lu, Eu, Dy and Ce in REEs group. The analysis shows high spatial variability of TE and REE concentrations in lake sediments. The values of geochemical indices point to low pollution of lakes sediments. The anthropogenic sources only for two lakes had an impact on concentrations of selected TEs and REEs. The analyses allowed to identify elements among TEs and REEs documenting geochemical processes and those indicating anthropogenic sources of pollution.

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Chemical Approaches to Remediate Heavy Metals

Singhal,

Parihar,

Khare

et al. 2023

Remediation of Heavy Metals

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Regional-scale mapping for determining geochemical background values in soils of the Itacaiúnas River Basin, Brazil: The use of compositional data analysis (CoDA)

Cited by 44 publications

References 76 publications

COVID-19 lockdown: a rare opportunity to establish baseline pollution level of air pollutants in a megacity, India

COVID-19 lockdown: a rare opportunity to establish baseline pollution level of air pollutants in a megacity, India

Causes of variations of trace and rare earth elements concentration in lakes bottom sediments in the Bory Tucholskie National Park, Poland

Chemical Approaches to Remediate Heavy Metals

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