Nickel toxicology testing in alternative specimen from farm ruminants in a urban polluted environment

The impact of nickel (Ni) metal toxicity, on public health was assessed analyzing forage samples (Acacia nilotica, Zea mays, Pennisetum glaucum, Capparis decidua and Medicago sativa), soils and blood samples of cow, buffalo and sheep (blood plasma, fecal, and hair) collected from three different agro-ecological zones and analyzed through atomic absorption spectrophotometer. Results showed that nickel values differed in soil samples ranging from 4.49 to 9 to 25 mg/kg, in forages from 3.78 to 9.53 mg/kg and in animal samples from 0.65 to 2.42 mg/kg. Nickel concentration, in soil and forage samples, was below the permitted limits. Soil with the minimum nickel level was found under C. decidua while the maximum concentration was reached under the A. nilotica. Among the animals, nickel was maximum in buffaloes that grazed on the Z. mays fodder. Ni was more accumulated in feces than other body tissues. The sheep and buffaloes showed high vulnerability to Ni pollution due to the highest contamination levels at site II and III. Bioconcentration factor, pollution load index and enrichment factor were found to be higher in buffaloes than cows, respectively. The daily intake and health risk index ranged from 0.0056 to 0.0184 mg/kg/day and 0.186–0.614 mg/kg/day respectively. In short, the results of this study evidenced that Nickel-containing fertilizers should never not be used to grow forage species. Government should to lessen the toxic metal accessibility to animals. Although general values were lower than the admitted limit, nickel can be accumulated and the consume of food containing nickel can increase health risks. General monitoring of soil and vegetation pollution load, as well as the use of other non-conventional water like canal water for forage irrigation could be a sustainable solution to decrease the access of nickel in the food chain.