Leafy vegetables are a rich source of iron and fibers for the human diet, which may become hazardous if exposed to heavy metal contamination. Cadmium (Cd) and lead (Pb) are two highly toxic metals even at trace concentrations. Engineered nanoparticles (ENPs) can alter the uptake of heavy metals and localization of essential minerals such as iron (Fe) through different mechanisms. The goal of this study was to understand the mutual effects of zinc oxide nanoparticles (ZnONPs) and coexisting heavy metals Pb 2+ and Cd 2+ on their uptake and accumulation as well as their effects on Fe concentrations in romaine lettuce (Lactuca sativa L. var. Longifolia) in a hydroponic system. At termination, shoots were gently separated from the roots, and the concentrations of Pb, Cd, Fe, and Zn in all plant tissues were quantified by inductively coupled plasma-mass spectrometry (ICP-MS). In addition, microbial density analysis in the growth media was performed for each treatment. The results indicated active interactions between ZnONPs and coexisting divalent heavy metals. ZnONPs significantly reduced the accumulation of Cd and Pb in roots by 49% and 81%, respectively. In shoots, Cd was reduced by 30%, and Pb elevated by 44%. Fe concentration in shoots was strongly affected by ZnONPs, and the total Zn in shoots was negatively correspond with the microbial population in the growth media. Exposure to ZnONPs alone increased the total Fe in shoots by 80% compared to controls, and the copresence of ZnONPs and heavy metals increased Fe concentration by about 77%. The results revealed the role of ENPs in governing the uptake and translocation of some essential elements and toxic heavy metals in plants.

No abstract

The need to feed 9.9 billion people by 2050 will require the coordination of farming practices and water utilization by nutrient-dense plants and crops. High levels of lead (Pb), a toxic element that can accumulate in plants, can lead to toxicity in humans. With the development of novel treatment technologies, such as atmospheric cold plasma (ACP) and engineered nanoparticles (NPs), the time to germination and levels of heavy metals in food and feed commodities can be reduced. This study provides insight into the impact of plasma-activated water (PAW) on the germination rates and effects of soybean seeds, and the resultant combination effects of zinc oxide uptake in the presence of lead. Soybean seedlings were watered with PAW (treated for 3, 5, and 7 min at 30, 50, and 70 kV), and the germination and growth rate were monitored for 10 days. The germinated seedlings were then grown hydroponically in a nutrient solution, and the biomass of each example was measured. The PAW treatment that resulted in the best growth of soybean seeds was then exposed to Pb and zinc-oxide nanoparticles (ZnONPs) to investigate heavy metal uptake in the presence of nanoparticles. After acid digestion, the rate of heavy metal uptake by the soybean plants was evaluated using inductively coupled plasma-mass spectrometry. The PAW seeds grew and germinated more quickly, demonstrating that the plasma therapy had an effect. The rate of heavy metal uptake by the plants was also shown to be 5x lower in the presence of ZnONP.

where she received a B.S. in Bio Environmental Engineering in 2006. She then began pursuing her graduate education at Purdue University in the Agricultural and Biological Engineering Department, completing her Ph.D. in 2015. Her primary research areas include 1) mycotoxin risk assessment and treatment in stored grains and 2) innovate instructional strategies for Biological and Agricultural Engineering students.