Assessing bioaccessible fractions of arsenic, chromium, lead, selenium and zinc in coal fly ashes

Abstract

The utility of a physiologically based extraction test for evaluating the bioaccessibility of metals from fly ash in the human gastrointestinal system was evaluated in the present research. Calcium-rich and silica-rich fly ashes collected from eight power plants in India and United States of America were assessed for bioaccessibility for arsenic, chromium, lead, selenium and zinc. The results from the physiologically based extraction test were compared with those from a sequential extraction procedure that is often applied to solid wastes. Based on the physiologically based extraction test results, more than 40 % of the arsenic was found to be bioaccessible for all the ashes while selenium was very accessible for the calcium-rich ashes. Lead was found to be insignificantly bioaccessible in calcium-rich as well as silica-rich fly ashes. The mobilization of metals in the first three steps of the sequential extraction procedure was similar to the mobilization in the physiologically based extraction test for selenium for all ashes and for arsenic and chromium for most ashes, but the sequential extraction procedure mobilized more zinc than did the physiologically based extraction test. These results indicate that while sequential extraction procedures can provide good estimates of the bioaccessibility of many elements, extraction tests that more closely simulate physiological conditions can provide more accurate measures of bioaccessible concentrations of metals.

Assessment of heavy metals and rheological characteristics of coal ash samples in presence of some selective additives

“…In contrast, the elements such as Cd, As, Co and Hg with higher molecular mass settle rapidly with bottom ash after combustion. Similar type of analysis results has been reported in the literature (Sushil and Batra 2006;Lokeshappa et al 2014). …”

“…The conventional dilute phase of ash slurry transportation system being practiced by the power plants causes leaching of heavy metals from the ash matrix in the ash ponds/dykes. The presence of these potentially toxic elements such as arsenic, cadmium, cobalt, lead, mercury, nickel and zinc can be considered hazardous for living organisms as they have tendency to leach out from fly ash at the disposal sites and contaminate the environment, especially surface and ground water (Sushil and Batra 2006;Senapati et al 2012;Singh et al 2014;Lokeshappa et al 2014;Chen et al 2014;Kosson et al 2014;Rind et al 2014;Krgovic et al 2015). The assessment of leaching behaviour of fly ash may be performed thoroughly prior to selection of appropriate disposal method for its adequate management (Dawle et al 2014).…”

Characterization, risk assessment, and potential utilization of fly ash from PLTSa Merah Putih at Bantargebang, Bekasi, Indonesia

“…This chromium accumulates in plants and affects their growth. Lead (Pb) is toxic to animals and human beings, especially young children, and has become a more serious concern [30]. However, to find out whether the by-product is dangerous or not, can be used or not, a characteristic test is needed to determine the hazard category.…”

Pemanfaatan Sludge Ash Pond PT. Cirebon Electrical Power (CEP) sebagai Bahan Bakar Alternatif

“…Salah satu metode pembuangan FABA melalui "wet disposal" dengan melakukan landfilling pada ash pond. Ash pond ini berfungsi sebagai area landfill basah untuk mencegah debu terbang ke udara (Lokeshappa & Dikshit, 2011;Isemin et al, 2017). Akan tetapi volume ash pond yang sangat banyak juga menimbulkan masalah baru, karena membutuhkan banyak ruang untuk menampungnya.…”