Monitoring of Soil Environment Under Influence of Coal Bed Water

Abstract

During the extraction of coal bed methane (CBM), entrapped in the deep layers of different coal beds, large amount of coal bed water (CBW) is also simultaneously released. The quality of this water is generally very poor which may often contaminate the adjoining soil environment adversely. In the present study, some major changes occurring in CBW-contaminated soils were assessed with relation to nearby non-affected soils. The CBW was found to be moderately saline and highly alkaline in nature with high sodium absorption ratio (SAR) values. Contamination with this water affected the soil environments substantially resulting in significantly increased pH and exchangeable sodium percentage (ESP) in the affected soils thus rendering the soils unsuitable for undertaking common agricultural practices. However, in spite of moderately high electrical conductivity values of this contaminating water, the resultant increments in salinity status of the soils were not observed to reach near the critical level. This behaviour was attributed to light texture of these soils which probably helped in leaching of a part of the soluble salts. Some microbial properties as well as availability of nitrogen and phosphorus were also found to decline in these CBW-affected soils. The study showed that utmost care needs to be exercised before release of CBW during extraction of CBM. In case of any contamination to nearby arable soils, suitable amendment practices for alkaline soils need to be adopted to mitigate the adverse effects of such water on soil environment.