Comprehensive assessment of pollution indices, sources apportionment and ecological risk mapping of heavy metals in agricultural soils of Raebareli District, Uttar Pradesh, India, employing a GIS approach

Abstract

AbstractIn the environment, heavy metal contamination is a well known problem due to its persistence and toxicity. Heavy metal pollution has significantly affected soil properties and functions, resulting in significantly increased land degradation as a result of anthropogenic interventions that include mining and various industrial and agriculture activities. While heavy metals pollution in soil have been studied very rarely in this District, this paper explores the current status of agricultural soil pollution by heavy metals in Raebareli. This study identifies heavy metals as well as their quantities in the soil and their spatial distribution; our study employed various pollutant indices and geographical information system (GIS) techniques. This research work evaluated the physiochemical properties, the pollution load index (PLI), contamination factor (CF) and the degree of contamination and geoaccumulation (Igeo) in sodic soils of the Raebareli District, Uttar Pradesh, India. Uchahaar site (US) has the most polluted soil, while the Bacharawa site (BS) has the least contaminated soil. The soil quality has degraded due to anthropogenic interventions at most sites. There is slight to moderate contamination by heavy metals at all sites. The Igeo values in subSites US1, US2 and US3 included high levels of Cu, Zn, Pb, Mn and Sr. SubSites BS2 and BS3 have high Sr levels and US1 has a high As level all these Subsites have high anthropogenic influences. The PLI values indicate that most of the study subSites come under a slightly polluted class, except US1 where the PLl was > 3 indicating severe heavy metal pollution at this site. All the pollution indices have then been utilized for building maps using the IDW method of interpolation. The spatial projection of PLI and ecological risk index (Er) values suggest that the northern part of Raebareli has a high pollution load and ecological risk in terms of heavy metal pollution. This study provide valuable information that policymakers could use to develop an appropriate plan to control pollution within the agricultural sector.