Application of fertilizers improves cadmium phytoextraction efficiency of Nasturtium officinale R.Br. grown in cadmium-contaminated water

Increasing toxic metal pollution in the aquatic ecosystem since the industrial revolution produces serious environmental challenges and has raised critical questions of ecological and human health implications. As a typical aquatic plant, Nasturtium officinale (N. officinale) has drawn significant attention due to its remarkable accumulation of heavy metals and other harmful substances from polluted water. The aim of this study is to investigate the cadmium (Cd) absorption capacity of N. officinale under different treatment conditions of Cd exposure and fertilizer application. Our experiments focused on the rapid Cd uptake by N. officinale over a concise 14-day duration. Results revealed that exogenous Cd introduction, either alone or combined with nitrogen (N), phosphorus (P), and potassium (K) fertilizers (0.5, 1, and 2 ppm), exerted a profound influence on various attributes of N. officinale. Cd absorption exhibited a wide range, spanning from 0.01 mg/L to a significant 2.23 mg/L. Notably, the lowest Cd accumulation occurred at 2 ppm, while the highest was observed at 0.5 ppm in conjunction with NPK fertilizer. Furthermore, individual applications of N, P, and K fertilizers at varying concentrations consistently promoted plant height, albeit at the cost of declining fresh biomass under Cd treatment. In summary, these findings underscore the potential of N. officinale as a Cd hyper-accumulator, emphasizing the necessity for caution when consuming this plant from industrially polluted waters. This research enhances our understanding of environmental pollution in aquatic ecosystems and offers valuable insights into tackling the ecological and health challenges posed by heavy metal contamination. The study showed that N. officinale is a promising, eco-friendly solution for removing Cd from water, with effective absorption and accumulation capabilities. The process is further optimized and made more cost-effective with the addition of low concentrations of NPK fertilizer.