Appraising growth, daily intake, health risk index, and pollution load of Zn in wheat (Triticum aestivum L.) grown in soil differentially spiked with zinc

Zinc (Zn) is a vital nutrient element required for plants normal growth and development. It performs imperative functions in numerous metabolic pathways in the plants. However, potentially noxious levels of Zn in terrestrial environment can lead to inhibited photosynthesis, growth, respiratory rate and imbalanced mineral nutrition. In micronutrient malnutrition, Zn deficiency is a global human health problem owing to the human dependence on cereals grains especially wheat-based diet. Therefore, this study investigated the Zn uptake efficacy in Triticum aestivum that is grown under two different doses (100 g/kg or 200 g/kg) of various soil amendments in both pot and field experimentation. Results of this study revealed that mean Zn concentration in different wheat varieties and treatments were varied from 1.53 to 6.03 mg/kg, 11.27 to 40.65 mg/kg, 11.28 to 39.93 mg/kg, and 11.32 to 37.70 mg/kg in amended soil, root, shoot, and grains, respectively. All observed Zn values in soil and wheat parts were lower than the FAO/WHO standards. Zinc values observed for pollution load index (0.034-0.134 mg/kg), daily intake (0.00492-0.01533 mg/kg), and health risk (0.0164-0.0570 mg/kg) index were lower than 1 except bio-concentration factor. Bio-concentration factor (5.076-10.165 mg/kg) revealed that DHARABI-11 variety showed maximum Zn uptake efficacy in farmyard manure treatment. The daily intake and health risk index values also showed that Zn level in grains is safe for inhabitants consumption. Overall, study recommended that these organic amendments are a good source of fertilizers, essentially required for the sustainable management of soil and increases the Zn accumulation in wheat grains which can ultimately reduce the Zn malnutrition in human food chain.

Evaluation of nickel toxicity in wheat as function of diverse type of fertilizers: implications for public health

Many studies have described the physiological, biochemical, and molecular responses to heavy metal toxicity and deficiencies individually in plants. The present study assess nickel (Ni) concentration in amended soil, plant vegetative parts, and wheat grains, grown under diverse types of fertilizers in Sargodha, Punjab, Pakistan. Different varieties of wheat were grown in pot and fields. Different treatments (municipal solid waste, poultry waste, press mud, farm yard manure) of fertilizers were applied in order to study the metal level increased in different parts (root, shoot, grain) of wheat due to fertilization. Results indicated that metal level was found highest in roots followed by shoot and grain. The highest level of nickel in root was present in V1 (2.35 mg/kg) due to T2 (2.60 mg/kg) treatment. Higher nickel levels in wheat shoot and grains were observed in V5 (2.36 mg/kg) and V8 (2.29 mg/kg), respectively, due to applied treatment T2 (2.57 mg/kg). This study concluded that treatment T9 was proven safe in view of the observed Ni concentration, while treatment T2 (municipal solid waste) resulted in higher accumulation of nickel in wheat grains which showed that municipal solid waste should be treated before their application in agriculture fields to secure the public health. This study recommended that although application of fertilizers increased the plant growth and nutritional value, it also enhanced metal accumulation in the wheat grains which could be harmful for consumers especially human being. Government should take actions to prevent metal toxicity in human food chain.