Pollution indices as useful tools for comparative potential health risks of nickel in water-soil-fodder-animals food chain in relation to spatial and temporal fluctuations

Abstract

Contamination of fodder species with elevated levels of metallic compounds holds significant epidemiological relevance, as it serves as the primary gateway for the introduction of these elements into the food chain. This investigation was directed to ascertain the ecological and health hazard of nickel contamination through various indices in food chain resulting from the dietary consumption of commonly ingested fodder crops cultivated on contaminated sites in the proximity of Sahiwal (Sargodha) and Soone Valley (Khushab), Punjab, Pakistan. Samples of water, soil, forages, ruminant’s blood, feces, and milk were collected from two sites; Soone Valley (Site_1) and Sahiwal (Site_2) in summer (Season_1) and winter (Season_2) during 2022-23, and were analyzed for nickel concentrations employing atomic absorption spectrophotometer. The mean concentrations of nickel were varied from 0.0125–0.0579 mg L− 1, 0.386–2.123 mg kg− 1, 0.00853–0.5784 mg kg− 1, 0.1085–0.5918 mg L− 1, 0.04664–0.2122 mg kg− 1, and 0.00820–0.2147 mg L− 1 in water, soil, forages, blood, feces, and milk, correspondingly. Highly significantly a negative correlation was observed among the soil vs fodder of Site_1 and Site_2 during both seasons. In animals, the highest nickel concentration was detected in blood of buffaloes at Site_1, while lowest in milk of cows at Site_2. Nickel concentrations were detected under standard permissible limits described by FAO/WHO. Except to BCF and EF, all the computed indices (PLI, Igeo, Eri, DIM, EDI, HRI, THQ, EDD, ECR, and ILTCR) were < 1, indicating low concentrations of nickel in soil and fodder, thus ensuring the safety of local ruminants upon ingestion during both seasons at both sites. Henceforth, strongly advocate the regular surveillance of heavy metal concentrations in the pasture grass surrounding contaminated locations is necessary. Furthermore, we suggest implementing precautionary measures to mitigate unintentional exposures of both livestock and, consequently, human beings to the deleterious effects of metal toxicity.