Bioavailability of molybdenum in soil and fodder crops: toxicity analysis and health risk assessment

Despite the rarity of molybdenum (Mo) metal in nature, significant quantities of Mo in industrial discharges have the potential to represent a serious threat when municipal sewage sludge is applied to agricultural land. Surprisingly little information is available about Mo uptake from sewage sludge-treated soils, especially in terms of field trials. This research looked at the bio accumulative pattern of molybdenum in plants grown at three different sites [Kahoot (32.3837 degrees N, 72.7082 degrees E), Wazidi (32.3917 degrees N, 72.7260 degrees E), and Jhawarian (32.3563 degrees N, 72.6210 degrees E)] of Sargodha district receiving ground water, canal water and sewage water. Concentration of molybdenum was evaluated in soil and water samples. Additionally, the level of molybdenum was also analyzed in hoof samples of animals raised on forage grown on sludge treated soils. Maximum level of molybdenum (43.263 +/- 0.3692 mg/L) was observed in water samples collected from SW-III receiving sewage water. Highest level of molybdenum accumulated in Avena sativa (20.903 mg/kg +/- 0.222) grown at site treated with sewage water. The metal detection in the soil samples among all three sites ranged from 15.96 to 35.59 mg/kg whereas same varied from 17.32 to 43.99 mg/L in water samples. Maximum molybdenum accumulation was observed in hair (3.588 mg/kg +/- 0.1252) and hoof (4.5429 mg/kg +/- 0.0933) samples collected from buffalos raised on forage grown on sewage waste water. Moreover, the soil in which these crops were grown was also evaluated to get pollution load index which ranged from 0.39 to 0.889. Further indices included BCF ranging from 0.30-0.64, EF: 1.25-2.65 and DIM: 0.04-0.009. Concentration of Mo in plants and soil treated with sewage water and ground water exceeded the international permissible limits.