Arsenic in coal of the Thar coalfield, Pakistan, and its behavior during combustion

Abstract

The aim of the current study is to evaluate the occurrence of arsenic in coal collected from Thar coalfield, Pakistan, and its behavior during the combustion. Fractionation of arsenic (As) in coal samples was carried out by Community Bureau of Reference sequential extraction scheme (BCR-SES) and single-step-based BCR method (BCR-SS). These methods are validated using the certified reference material of sediment BCR 701 and standard addition method. The stepwise fractions of As in laboratory-made ash (LMA) have been also investigated. The extractable As content associated with different phases in coal and LMA samples were analyzed by electrothermal atomic absorption spectrophotometer. The extraction efficiency of As by BCR-SS was slightly higher than BCR-SES, while the difference was not significant (p < 0.05). The BCR-SS method is a time-saving method because it can reduce the extraction time from 51 to 22 h. The As contents in LMA revealed that during combustion of the coal, >85 % of As may be released into atmosphere. The relative mobility of As in the coal samples was found in increasing order as follows: oxidizable fraction < reducible fraction < acid soluble fraction. The total and extractable As obtained by BCR-SES and BCR-SS were higher in coal samples of block III as compared to block V (p > 0.05).

Evaluation of the fate of arsenic-contaminated groundwater at different aquifers of Thar coalfield Pakistan

“…1) (Ali et al 2015) in the south eastern part of Sindh, on the stable western margin of the Indian Plate. The study area has a tropical desert climate (Imran et al 2014).…”

“…Nowadays, several national and international agencies are working on different projects in Thar coalfield (Ali et al 2015;Imran et al 2014). The discharge of pollutants from surface mining operations generally occurs during or immediately following periods of excessive precipitation (Tripathy 2002).…”

“…Coal combustion not only produces heat and energy but also significantly harms the environment and human health (Singh et al 2012). Under leaching action, the ashes will find their way into groundwater, causing contamination (Panhwar et al 2015;Singh et al 2012). A few scholars have done work on the impact of coal mining on the shallow groundwater (Li et al 2011).…”

Monitoring of arsenic fate with proximate parameters and elemental composition of coal from Thar coalfield, Pakistan

“…(Ali et al, 2015). Thar coalfield is divided into twelve blocks according to the private power and infrastructure board, federal ministry of water and power government of Pakistan.…”

Evaluates the chemical fractions of arsenic bounded to solid matrixes of thar coalfield of pakistan by sequential extraction method

“…Coal rank of Thar coalfield is lignite and it is also divided into 12 blocks for mining purpose [20]. Metamorphic rocks of Proterozoic to Late Proterozoic age are exposed in Karunjhar Hill [21]. Metamorphic rocks of Proterozoic to Late Proterozoic age are exposed in Karunjhar Hill [21].…”