Evaluation of potential ecological risk assessment of toxic metal (lead) in contaminated meadows in the vicinity of suburban city: soil vs forages vs livestock.

Heavy metal toxicity is becoming an increasing concern for environmental, human and animal health. The current research analyzed the lead (Pb) contamination in the food chain under three different irrigation sources (ground, canal, and wastewater). Soil, plant and animal samples were collected from the Jhang district of Pakistan and processed with an atomic absorption spectrophotometer. Lead concentration varied in the samples as: 5.22-10.73 mg/kg in soil, 2.46-10.34 mg/kg in forages and 0.736-2.45 mg/kg in animal samples. The observed lead concentration in forage and animal blood samples was higher than the standard limits. The pollution load index (0.640-1.32) in soil showed that lead contamination mainly took place at the wastewater irrigating sites. Bio-concentration factor values (0.313-1.15) were lower than one in all samples except Zea mays, showing that lead metal was actively taken up by Zea mays tissues from the soil. Enrichment factor values ranged from 0.849-3.12, showing a moderate level of lead enrichment. Daily intake and health risk index varied between 0.004-0.020 mg/kg/day and 0.906-4.99, respectively. All the samples showed maximum lead concentration at the wastewater irrigating site compared to the ground or canal water application sites. These results recommended that consistent application of wastewater for forage irrigation must be avoided to prevent health hazards associated with lead in the animal and human food chain. Government must implement adequate strategies to protect the animal and human health from the harms of toxic heavy metals.

Cobalt availability in the soil plant and animal food chain: a study under a peri-urban environment.

Cobalt metal is considered as an essential trace element for the animals. Present investigation was undertaken in the peri-urban area to analyze the cobalt availability in animal food chain by using different indices. Cow, buffalo and sheep samples along with forage and soil samples were collected from the three different sites of District Jhang and analyzed through atomic absorption spectrophotometer. Cobalt values differed in soil samples as 0.315-0.535 mg/kg, forages as 0.127-0.333 mg/kg and animal samples as 0.364-0.504 mg/kg. Analyzed cobalt concentration in soil, forage and animal samples was found to be deficient in concentration with respect to standard limits. Soil showed the minimum cobalt level in Z. mays while maximum concentration was examined in the forage C. decidua samples. All indices examined in this study has values lesser than 1, representing the safer limits of the cobalt concentration in these samples. Enrichment factor (0.071-0.161 mg/kg) showed the highly deficient amount of cobalt enrichment in this area. Bio-concentration factor (0.392-0.883) and pollution load index (0.035-0.059 mg/kg) values were also lesser than 1 explains that plant and soil samples are not contaminated with cobalt metal. The daily intake and health risk index ranged from 0.00019-0.00064 mg/kg/day and 0.0044-0.0150 mg/kg/day respectively. Among the animals, cobalt availability was maximum (0.0150 mg/kg/day) in the buffaloes that grazed on the C. decidua fodder. Results of this study concluded that cobalt containing fertilizers must be applied on the soil and forages. Animal feed derived from the cobalt containing supplements are supplied to the animals, to fulfill the nutritional requirements of livestock.