Abstract
The increasing atmospheric concentration of lead (Pb) poses a serious threat to environmental health and crop productivity, ultimately resulting in health hazards for humans worldwide. The current study evaluated the effects of foliar-applied lead oxide nanoparticles (PbO-NPs) on the Pb uptake, morphological attributes, and physiochemical changes in rice crops, as well as the potential health implications for humans. A pot experiment was conducted in which rice plants were applied with foliar spray with three different levels of PbO-NPs (0, 10, & 50 mg/plant). The findings indicated that a significant quantity of Pb accumulated in the shoot (15.42 µg/kg) with a comparatively lower amount (4.09 µg/kg) translocated to roots under the highest level of PbO-NPs application. Pb residue inside rice plants led to a considerable reduction in total chlorophyll contents (82%) and photosynthetic rate (81%). Following Pb accumulation, there was a significant decrease in antioxidant enzyme activity and increase in ROS production. At highest level of PbO-NPs (50 mg/plant), a substantial reduction in POD (82.34%), SOD (73.085%), CAT (62.245%), and APX (55.02%) was observed. Conversely, a remarkable increase was observed in MDA (76.10%), H(2)O(2) (70.06%), and electrolyte leakage (21.85%). Based on the amount of Pb accumulated in rice grains, the estimated daily intake (EDI) exceeded the permissible levels of FAO/WHO standard, resulting in a health risk index (HRI) > 1, indicating that the health risk posed to the consumer is severe. Overall, the results indicate that foliar application of PbO-NPs at a higher concentration 50 mg/plant) caused detrimental effects on morphological, physiochemical attributes, as well as and antioxidants enzymes activity. The finding of our study clearly suggests that the deposition of atmospheric Pb in rice producing areas may pose significant food safety concerns and lead to serious health risks to human through dieting exposure.