An integrated analysis of sinkholes in Kadapa region, Andra Pradesh, India: Implication to pedology

Abstract

Sinkholes are one of the common karst features of geographical formations, which come into existence due to the dissolution of underneath lime-rich formations and subsequent collapse of the ceiling of the holes. Since sinkholes are formed in agricultural lands, this study aimed to understand the impact of sinkhole formation on heavy metals and minerals by collecting samples from sinkholes from various localities of Kadapa District of the state of Andhra Pradesh in India. The heavy metals were determined by ICP-AES analysis and characterization of soils in sinkholes was carried out. The FTIR spectroscopic technique was utilized to identify the minerals present in sinkholes. The XRD and SEM techniques were used to assess clay mineral composition and particle size and morphology of soil samples, respectively. Following the available literature, the minerals were identified from the location or band position of peaks from the Infra Spectrum. The minerals found were Quartz, Cesium di alumino tri silicate hydrate, Natrolite (Cs), Sodium Rhodium Oxide, Cobalt Uranium, Cesium Manganese Fluoride Hydrate, Quartz alpha, alpha-Si O2, Di copper (I) oxide, Erbium Indium Silver. Subsequently, we assessed the consequence of heavy metal pollution on soil microorganisms in sinkholes. The total population of microorganisms (bacteria, fungi, actinomycetes) was found to be decreased with increasing concentration of heavy metals.Additional analysis identified the bacteria resistant to Zinc, Manganese, lead (2 mM), copper (5 mM) metals. In sum, the findings from our integrated analysis of sinkholes provide an understanding of local pedology of the Kadapa region in India with implications for safety measures, agriculture land management and productivity.