Assessment of heavy metal contamination and soil fertility in the industrial belt of Sandila, Uttar Pradesh: Implications for aromatic crop cultivation

Heavy metal pollution in agricultural soils due to anthropogenic activities like industries and agrochemicals is a major concern all over the world. This study aims to evaluate soil fertility and heavy metal pollution in selected sites of the Sandila area, Uttar Pradesh, India. The composite soil samples were collected in industrial sites (I), surrounding agricultural farmlands (F) in Sandila, and the CIMAP farm as a control (C). The physicochemical properties, heavy metal content, and soil pollution indices like the geo-accumulation index, single pollution index, enrichment factor, contamination factor, and ecological risk factor were analyzed. Soil pH varied across sites—acidic in industrial (I), alkaline in farmland (F), and neutral in control (C). Nutrient levels differed significantly: available nitrogen was low in I (188.16 kg/ha) but high in F (616.75 kg/ha) and moderate in C (292.7 kg/ha). Phosphorus (P₂O₅) and potassium (K₂O) ranged from high (99 kg/ha, 309.44 kg/ha) in I to medium (27.93–252.52 kg/ha) in F and lower (22.35–126.03 kg/ha) in C. The mean elemental concentration in soils was in decreasing order as Zn > Pb > Cu> Cr > Ni > Ba > Fe > Mn > Co. Pb and Cu were major heavy metals contaminated in I and F sites. To mitigate heavy metal contamination, phytoremediation using aromatic crops is recommended.