Quantitative Assessment of Variability and Uncertainty of Hazardous Trace Element (Cd, Cr, and Pb) Contents in Chinese Coals by Using Bootstrap Simulation

Abstract

The quantitative measurements of uncertainties regarding the contents of hazardous trace elements (HTEs) serve as a basis for better assessment of the geochemistry and mineralogical characteristics of coals and their environmental impacts. In this paper, by using bootstrap simulation methodology, a quantitative procedure was demonstrated to characterize the variability and uncertainty of HTE (Cd, Cr, and Pb) contents in Chinese coals, which were specified by 27 different provinces and mining areas. Original data samples for Cd, Cr, and Pb contents in Chinese coals were compiled and summarized from the results reported in published literature. Sampling distributions for uncertainties in statistics such as the mean, median, and confidence interval were calculated. The national average contents were estimated at approximately 0.61 g/g for Cd, 30.37 g/g for Cr, and 23.04 g/g for Pb. The ranges of uncertainties for bootstrap samples of national HTE contents were nearly symmetrical, and the ranges of the 95% confidence interval for the arithmetic mean were relatively small, with relative uncertainties of Ϫ16.39% to ϩ21.31% for Cd, Ϫ10.11% to ϩ11.72% for Cr, and Ϫ8.55% to ϩ8.64% for Pb.

Atmospheric emission inventory of cadmium from anthropogenic sources

“…The statistical data of coal consumption and detailed emission factors are adopted to calculate the atmospheric emissions of Cd from coal burning. In this study, the methodologies for determining the average content of Cd in coals as produced and consumed at provincial levels are consistent with the previous detailed analysis, the detail algorithms for determining Cd content in coals as consumed, cleaned coals, coal briquettes, and cokes as produced can be referred to the previous studies (Tian et al 2010(Tian et al , 2011(Tian et al , 2012a. The data sources and final Cd content in coal products as consumed are listed in Table S1-S4 of the Supplemental Information (SI).…”

“…Based on the results of variability analysis of Cd content in coals by bootstrap simulation (Tian et al 2011(Tian et al , 2012a, the Monte Carlo simulation is used to quantify the uncertainty of Cd emissions depending on available activity data and emission factors distribution. The emissions of anthropogenic sources with uncertainty (95 % confidence interval around the arithmetic mean value) are shown in Table 3.…”

Atmospheric Emission Characteristics and Control Policies of Five Precedent-Controlled Toxic Heavy Metals from Anthropogenic Sources in China

“…To make up the deficiency brought by using simple arithmetic mean value of HMs content of limited coal samples with large data distribution range as the representative of a whole province, bootstrap simulation methodology is used to characterize the variability and uncertainty of HMs contents in Chinese coals; more details can be seen in SI Section S1. 24,25 Data source samples of HMs content in Chinese coals by provinces from published literature are shown in SI Tables S1−S5, and statistical parameters of bootstrap mean contents by provinces and coal bearing areas are shown in SI Table S6 and Figure S4. S7.…”

Temporal and spatial variation characteristics of atmospheric emissions of Cd, Cr, and Pb from coal in China

“…First, the average content of each of these elements in coal as produced on a provincial-level are determined by using a bootstrap simulation (Tian et al, 2011). Then, the weighted average content of Cd, Cr, and Pb in coal products as consumed are calculated by combining the annual coal flow matrix among 30 provinces in the Chinese mainland as described in our previous studies (Tian et al, 2010(Tian et al, , 2011. The procedures and source samples for determining the average contents of Cd, Cr, and Pb in Chinese coal by provinces can be referred to in Tables S1eS4 in the supplementary materials for details.…”