## 3 Results and Discussion
### Pot Assays
Similarly, HA combined with a hydrated lime and an organic fertilizer were effective in decreasing Cd uptake in rice and wheat under a rice-wheat rotation system, leading to improved crop yields [54]. \begin{table}
\begin{tabular}{c c c c c c} \hline
**Soil + HANPs** & **Cd (mg kg\({}^{-1}\))** & **Germination (\%)** & **Pb (g)** & **Db (g)** & **h (cm)** \\ \hline - & 0 & 92 \(\pm\) 8 a & 16.4 \(\pm\) 0.5 a & 1.6 \(\pm\) 0.4 a & 48.9 \(\pm\) 8.2 a \\
1\% & 0 & 95 \(\pm\) 3 a & 15.3 \(\pm\) 1.2 a & 2.4 \(\pm\) 0.4 a & 48.3 \(\pm\) 2.5 a \\ \hline - & 5 & 95 \(\pm\) 5 a & 12.5 \(\pm\) 2.5 b & 1.1 \(\pm\) 0.6 b & 39.2 \(\pm\) 13.2 ab \\
1\% & 5 & 95 \(\pm\) 2 a & 14.0 \(\pm\) 2.4 ab & 2.0 \(\pm\) 0.5 b & 47.0 \(\pm\) 1.3 a \\ \hline - & 10 & 75 \(\pm\) 14 b & 10.4 \(\pm\) 2.8 bc & 1.1 \(\pm\) 0.4 bc & 33.5 \(\pm\) 7.1 bc \\
1\% & 10 & 75 \(\pm\) 12 b & 12.9 \(\pm\) 2.4 b & 0.9 \(\pm\) 0.3 c & 47.3 \(\pm\) 4.2 a \\ \hline - & 25 & 58 \(\pm\) 10 bc & 6.0 \(\pm\) 2.9 c & 0.6 \(\pm\) 0.1 c & 26.5 \(\pm\) 4.7 bc \\
1\% & 25 & 55 \(\pm\) 9 c & 7.2 \(\pm\) 2.0 c & 0.8 \(\pm\) 0.2 c & 33.1 \(\pm\) 9.1 bc \\ \hline - & 50 & 42 \(\pm\) 16 d & 7.0 \(\pm\) 0.8 c & 0.7 \(\pm\) 0.3 cd & 25.1 \(\pm\) 3.8 c \\
1\% & 50 & 60 \(\pm\) 4 c & 3.1 \(\pm\) 1.4 d & 0.5 \(\pm\) 0.2 d & 20.1 \(\pm\) 4.7 c \\ \hline
**Soil + HANPs** & **Cd (mg kg\({}^{-1}\))** & **La (cm\({}^{2}\))** & **N\({}^{\circ}\)** & **Root-Cd** & **A.p.-Cd** \\  & & & **leaves** & **(mg kg\({}^{-1}\))** & **(mg kg\({}^{-1}\))** \\ \hline - & 0 & 11.3 \(\pm\) 2.6 a & 31 \(\pm\) 5 b & nd & nd \\
1\% & 0 & 8.0 \(\pm\) 2.2 ab & 37 \(\pm\) 3 a & nd & nd \\ \hline - & 5 & 6.6 \(\pm\) 4.3 ab & 39 \(\pm\) 4 ab & nd & 55.1 \(\pm\) 17.0 c \\
1\% & 5 & 7.8 \(\pm\) 5.1 ab & 42 \(\pm\) 3 a & nd & 16.4 \(\pm\) 3.6 d \\ \hline - & 10 & 8.5 \(\pm\) 3.6 b & 30 \(\pm\) 2 b & nd & 89.5 \(\pm\) 3.6 b \\
1\% & 10 & 6.4 \(\pm\) 5.0 ab & 31 \(\pm\) 5 b & nd & 27.6 \(\pm\) 8.8 d \\ \hline - & 25 & 5.4 \(\pm\) 2.1 b & 24 \(\pm\) 1 d & nd & 153.8 \(\pm\) 45.2 ab \\
1\% & 25 & 5.8 \(\pm\) 4.0 ab & 35 \(\pm\) 3 b & nd & 56.0 \(\pm\) 3.1 c \\ \hline - & 50 & 4.8 \(\pm\) 3.2 b & 28 \(\pm\) 2 c & nd & 215.7 \(\pm\) 43.3 a \\
1\% & 50 & 3.7 \(\pm\) 3.0 b & 26 \(\pm\) 2 c & nd & 91.9 \(\pm\) 10.2 b \\ \hline \end{tabular}  
* Pb: fresh biomass; Db: dry biomass; h height. La: leaf area; N\({}^{\circ}\) leaves: average number of leaves per individual; Root-Cd: Cd content in root: A,p-Cd: Cd content in aerial part; nd: not detected. Different letters next to the values in each column represent significant differences among treatments for each measured variable at a significance level of \(p<0.05\).  
\end{table} 
Table 5: The germination and physiological characteristics of quinoa for different treatments with Cd and HANPs in pot experiments at the end of the assays. Likewise, HA and humic acid application on alkaline soils contaminated with Cd also led to significant reductions in Cd concentrations in grains, shoots, and roots of wheat [55]. Other studies also showed that the co-application of HANPs with other (nano)materials improved Cd fixation in contaminated soils. For example, the combined application of zinc oxide and HANPs enhanced Cd immobilization and wheat growth, indicating that synergistic effects between different nanoparticles may be beneficial [56]. Also, combining a porous biochar composite with HANPs effectively immobilized Cd in soils [57], and combining HANPs with Fe\({}_{3}\)O\({}_{4}\) nanoparticles improved the stress caused by high Cd concentrations in rice seedlings, promoting growth and reducing metal accumulation [58]. However, our results indicate that Cd content in quinoa increases with the concentration of Cd applied to the soil, suggesting that while HANPs can reduce Cd bioavailability, their efficacy may vary depending on plant species and specific soil conditions.