Accumulation of Heavy Metals in Radish (Raphanus sativus) Irrigated with Water from Outflow of Ramgarh Lake, Gorakhpur, U.P., India

Abstract

The increased use of polluted water sources for irrigation poses serious risks of heavy metal contamination in agricultural soils and food crops in developing countries. This study investigated the accumulation of six heavy metals namely lead (Pb), cadmium (Cd), arsenic (As), copper (Cu), chromium (Cr) and zinc (Zn) in soil and radish plants (Raphanus sativus) irrigated with polluted water from Gura Nala, the outflow channel of Ramgarh Lake, Gorakhpur, Uttar Pradesh. A pot experiment was carried out for two consecutive years (September 2024 and September 2025) with two treatments; control (tap water irrigation) and polluted water irrigation. Heavy metal concentrations in soil and plant samples (leaves and edible roots) were analyzed by atomic absorption spectrophotometry. Results showed that concentrations of heavy metals in soil and all parts of plants were significantly higher in the irrigated with polluted water than control in both years. The highest accumulation was in the edible root part with Pb (1.552 ppm in 2024; 1.617 ± 0.035 ppm in 2025), Cd (0.015 ppm; 0.016 ± 0.001 ppm), As (0.020 ppm; 0.022 ± 0.001 ppm), Cu (0.511 ppm; 0.523 ± 0.015 ppm), Cr (0.091 ppm; 0.094 ± 0.004 ppm), and Zn (0.404 ppm; 0.410 ± 0.010 ppm). One-sample t-test analysis indicated statistically significant year-over-year increases for Pb in treated soil (p = 0.026) and for Pb (p = 0.049) and As (p = 0.037) in edible roots. The levels of metals in the edible roots of treated plants were above permissible limits of FAO/WHO for Pb, Cd and As. The study points to progressive heavy metal contamination in the Ramgarh Lake system and stresses the urgent need for remediation strategies, regular monitoring and public health interventions.

Keywords: Heavy metals, Raphanus sativus, Ramgarh Lake, wastewater irrigation, bioaccumulation, food safety, temporal trends, Gorakhpur