Characterization and Risk Evaluation of Tea Industry Coal Ash for Environmental Suitability

Abstract

Overload of coal ash (CA) generated from several coal fired plants poses acute problems of disposal and contamination of soil and water resources. Since CA generated from tea factories has not yet been characterized from environmental viewpoints, we attempted to critically characterize the agro-ecological compatibility of CA samples (CA1, CA2, CA3, and CA4) collected from four distantly located tea factories. Among these samples, we found CA3 and CA4 to have low pH and high metal content. Accordingly, we restricted our study to predict the solubility pattern of non-metal and metal ions in CAs by adopting a geochemical model (Visual MINTEQ). Various fractions of metals like Fe, Mn, Cu, Zn, Cr, Ni, and Pb were studied to figure out the mobility pattern of metals in the environment. The results clearly indicate that tea industry derived CA substantially differs from thermal power plant CA as regards several physico-chemical properties, for example, sandy texture, low pH and high nutrient content. Risk evaluation of human exposure to trace elements and the metal fractionation study led us to conclude that CA1 and CA2 are highly compatible with agricultural use.

Evaluación de material particulado en cenizas de fondo de carbón y sus posibles efectos ecotóxicos: estudio preliminar

“…The unburned carbon content was also measured with the loss on ignition (LOI), for which 22.81%, 16.65%, and 30.62% were obtained (see Table 1) for CFC 1, CFC 2, and CFC 3 respectively. Similar results have been reported by other authors (27,29), which is attributed to proportions of unburned coal; where the latter has been reported with high levels of PHA (13). Concerning toxicity, it has been found that one of the most frequent occupational risks is the risk of contracting cancer due to exposure to byproducts of coal combustion, due to the content of PHA and radioactive natural radionuclides, either by ingestion or dermal contact (4,37).…”

“…In this sense, CFCs are characterized by being granular with an irregular hexagon structure and visibly porous (13, 26 -28). The morphology of unburned carbon in CFC appears as irregular shapes for the same technique (29). Silva & Da Boit (19) studied CFCs using SEM and found concentrations of ultrafine spherical particles and nanoparticles smaller than 50 nm, rich in silica crystals and predominance of fine quartz grains; where exposure to these crystals is related to the incidence of lung cancer.…”

“…Alkaline pH can also reduce the bioavailability of metals ( 21). An acidic pH in coal ash can lead to total organic carbon (TOC) and S in the source coal (29). The literature reports on the application of ash as a soil amendment, however, this should not be generalized because investigations of the physical and chemical characteristics of the site need to be carried out before use.…”

Solubility, hydrogeochemical impact, and health assessment of toxic metals in municipal wastes of two differently populated cities

“…We determined water-soluble concentration of different elements in the MSW samples following Bhattacharyya et al (2011) and Goswami et al (2014). The samples were mixed with distilled deionized water (1:10 (w/v)) in conical flasks.…”

Evaluation of Tea Industrial Waste Ashes in Concrete Production

“…Bununla birlikte, atık kül bileşenleri, toprak ve su kaynaklarını büyük ölçüde kirleten hem çözünür hem de çözünmeyen ağır metaller içermektedir [7]. Ayrıca uzun vadeli tarımsal uygulamalarda kullanımının toprak sağlığını etkileyebileceği ancak insan sağlığı risk analizi sonuçlarına göre ise, tüm çay fabrikası atık küllerinin metal konsantrasyonlarının, potansiyel kanser risk seviyelerinin altında olduğu belirtilmiştir [8].…”