Assessment of Heavy Metals in Samples of Soil, Water, Vegetables, and Vital Organs of Rat (Bandicota bengalensis) Collected from Adjoining Areas of Polluted Water Body

The aim of the present study was to evaluate the status of heavy metal contamination in the samples of soil, water, vegetables, and vital organs (liver and kidney) of predominant species of rat i.e. Bandicota bengalensis, collected from the vegetable fields near Buddha Nullah (a seasonal water stream highly contaminated with domestic and industrial waste), Ludhiana, Punjab, India. The samples of soil, water, and vegetables and rat species were collected from the three sites (villages), viz., site I (Baran Hara), site II (Balloke), and site III (Jassian) lying in the vicinity of Buddha Nullah (contaminated site) and one site at Punjab Agricultural University, Ludhiana, Punjab, India (reference site IV). The results of the present study revealed significantly higher (p < 0.05) concentration of Cd, Cr, Mn, Ni, Pb, and Zn in soil samples and significantly higher (p < 0.05) concentration of As, Cd, Cr, Mn, and Pb in water samples collected from at all the three sites near Buddha Nullah as compared to reference site IV. In comparison to permissible limits given by SEPA (2016). (Swedish Environmental Protection Agency: Methods for inventories of contaminated sites. ISSN: 0282–7298.) and WHO (2017). (Guidelines for drinking-water quality. Fourth edition Incorporating the first addendum. pp 1–631.). Guidelines for drinking-water quality. Fourth edition Incorporating the first addendum. pp 1–631.), the concentration of Cd was found to be beyond the permissible limits in soil samples and concentration of As, Cd, Cr, Zn, and Pb was observed to be beyond the permissible limits in water samples collected from sites I, II, and III near Buddha Nullah. Heavy metals were present at significant concentrations (p < 0.05) in the samples of eight different vegetables collected from sites I, II, and III as compared to reference site IV. Heavy metals viz. As, Cd, Mn, and Zn and Mn, Ni, and Zn were found to be significantly higher (p < 0.05) in liver and kidney, respectively of the predominant rats collected from vegetable fields of sites I, II, and III as compared reference site IV. Histopathological studies in liver tissue of rats collected from sites I, II, and III determined the infiltration of leucocytes, dilation in central vein, pyknotic cells, increased Kupffer cells, and dilated sinusoidal spaces whereas renal tissue confirmed the degeneration of glomerular tuft and renal tubules, pyknotic nuclei in the cytoplasm and cytoplasmic vacuolization. Site I was concluded to be the prominent heavy metal contaminated location as the concentration of heavy metals in soil, water, vegetables, and rat organs (liver and kidney) collected from site I was the highest in comparison to sites II, III, and reference site IV. The calculation of transfer factor (TF) revealed the transfer of heavy metals from soil to vegetables at the contaminated sites which further intensifies the severity of heavy metal toxicity. Therefore, the results necessitate to avoid the application of water from unspecified or polluted water bodies for irrigation in agricultural fields and the urgency to purify the polluted water bodies such as Buddha Nullah to reduce the potential ecological risk in the environments.