Monitoring and Prediction of Fugitive Dust Concentration in Mechanized Opencast Coal Mine

Abstract

Atmospheric pollution due to particulate matter (PM) in opencast coal mining area is a very critical environmental issue. Nowadays in India, around 92% of the coal is produced by opencast mining method, which generates huge quantities of respirable PM by the processes like drilling, blasting, transportation, loading, unloading and mine fires. Further, mechanization in mines lead to add a heavy load of PM to the surrounding area. The particulate matter not only affects the human but also have tremendous effects on nearby flora and fauna by degrading the ecological environment in many ways. Most of the pulmonary diseases related to air pollution are generally directly or indirectly related to the physical and chemical characteristics of respirable PM (PM10). The monitoring and evaluation of PM concentration is the first important step in controlling PM level. So it becomes necessary to characterize the PM along with the monitoring for better source management.

This thesis mainly focuses on the measurement and characterization of respirable PM in and around a mechanized opencast coal mine of Talcher coalfields, Odisha. The study was carried out for a period of one year from March 2015 to February 2016, and seasonal variations of PM concentration was studied. The monitoring of particulate concentration revealed that the concentration of both PM10 and PM2.5levels were far above the standard limit of NAAQS, 2009. The trace metal study by atomic absorption spectrophotometer (AAS) indicated the presence of high concentration of Cd in the study area with Hg and Se. The concentration of Ni and As was found above the NAAQS, 2009 at most of the stations. The source apportionment study by using statistical techniques suggested the dominance of Cu, Pb, Cd, and As in PM10 of the study area indicated vehicular emission, coal transportation, coal burning, running of mine machineries, and windblown earth crust material were the principal sources of PM pollution. The correlation analysis supported the relationship between different parameters. Qualitative analysis was performed using FTIR, and XRD. The FTIR study showed the presence of different functional groups like hydroxyl, methyl, carboxylate, aldehyde, inorganic carbonate, sulphonate etc. in the PM10 with strong mineral bands of quartz, kaolinite, sepiolite, cerussite and nacrite at all the stations. The study from the XRD analysis of the PM10 samples showed that minerals such as Kaolinite, gypsum, siderite, quartz, hematite, illite, and dolomite were the most common minerals found in the PM10 in all the samples of the study area. Quartz was detected as dominated mineral. Secondary found minerals containing heavy metals like claudetite, mimetite, morenosite, and tiemannite were detected in the study area in trace amount. The health risk was calculated for the people residing near to the mining area due to presence of quartz in respirable air and found above the standard limit at most of the stations. The health risk was also assessed from the trace metals for both children and adults. The excess cancer risk (ECR) for children and adults were estimated to evaluate the cancerous risk due to individual as well as combined effects of metal (ECR Total). The HQ values for Cr and Cd were found above the safe limit in that area for both children and adults. Likewise the ECR values for Cr and Cd also were at a very risk level for both the age group. The HI and ECRTotal values were found above the safe limit which indicate the combine effect of trace metal on the children and adult were at a very high risk level in the study area. Finally AERMOD software was used to predict the PM concentration at different receptor locations and compared with the observed PM concentration to calculate the baseline concentration of PM in the study area. Further by using the model different locations were identified around the mine having PM concentration above NAAQS, 2009.