Examining Contamination of Arsenic in Soil Around Thermal Power Plant at Dadri in India

Abstract

Coal fired thermal power plant (TPP) serves as point source releasing hazardous heavy metals in the environment contributed from burning of coal for electricity generation. This causes altered physicochemical properties of soil. Arsenic (As) is highly toxic in nature which gets transferred to the soil environment by varied pathways. The present study attempts to measure the physicochemical properties and arsenic contamination in soil around a coal fired thermal power plant in India for two consecutive years (2017-19). The soil pH, moisture, conductivity, water holding capacity, nitrogen, phosphate, potassium, manganese, iron and arsenic were measured in six villages located within 0-10km around TPP. Results suggest soil from the villages to be slightly alkaline with good water holding capacity and soil moisture. The soil was manganese deficient however the levels of nitrate, phosphate and potassium were similar to that of agricultural soil suggesting negligible impact of TPP on soil quality in the region. Low arsenic contamination (though within permissible limits), at site 4 (Piyawali) located within 0-5 km and in windward direction from TPP was noted. Traces of as was also measured at site 2 (Jarcha) and site 3 (Khatana) which were within 5-10 km of TPP and in the windward direction. Results indicate that arsenic from the emissions migrate with the wind to Jarcha and Khatana whereas it directly falls and retains at Piyawali which is in the leeward direction. Thus, a significant relation between movement of arsenic and the position of the village, distance and direction of wind with respect to TPP is evident. The soil pollution index (Pi) for arsenic revealed the Pi values to be <1 in all seasons suggesting that though arsenic is present in the soils of the villages near the thermal power plant, it may not be contributing largely towards the pollution in the soil. Application of zinc to bind arsenic electrostatically in the soil matrix is therefore recommended to mitigate arsenic or growing of non-edible or energy rich crops will be helpful. Moreover, power plants be geared for arsenic containment measures to minimize input of arsenic in soil environment.