Screening various plant species to act as hyperaccumulators and associated health risks could serve as a sustainable solution for the bioremediation heavy metals (HMs). For the first time, the present study explored the phytoremediation potential of native plants, soil enrichment, and human health risks associated with the contamination of HMs in soil and plant samples collected from a municipal solid-waste open dump site. Soil and plant samples (n = 18 + 18) from the dumpsite and (n = 18) from the control site were analyzed for selected HMs, i.e., Chromium (Cr), Lead (Pb), Nickel (Ni), Iron (Fe), and Zinc (Zn). The phytoremediation potential of plants was assessed using the bioaccumulation factor (BAF), bioaccumulation coefficient (BAC), and translocation factor (TF), while soil pollution levels were evaluated using the contamination factor (CF), geoaccumulation index (Igeo), enrichment factor (EF), potential ecological risk index (PERI), and human health risk indices. The results revealed that based on TF and BAC values, Alhagi maurorum Medic., Astragalus creticus Lam., Cichorium intybus L., Berberis lycium Royle, and Datura stramonium L. were hyperaccumulators for Cr while Parthenium hysterophorus L. was a promising species for both Ni and Cr. Similarly, CF values for Fe, Ni, Pb, and Cr were >6, thereby showing very high contamination, while Igeo values for Fe, Ni, Pb, and Cr were (class 6, >5), showing that the soil was extremely polluted. Furthermore, EF values for Fe, Ni, Pb, Cr, and Zn were 2 < EF ≤ 5, depicting moderate enrichment, while PERI values were in the range of 91.31–195.84, employing moderate ecological risks (95 < PERI < 190) from the dumpsite’s soil. Moreover, for non-carcinogenic exposure, none of the analyzed metals exceeded the threshold limit HRI values > 1 in both adults and children. Likewise, in the case of carcinogenic effects, the CRI values were lower than the tolerable limits (1 × 10−6–1 × 10−4) in both adults and children. Moreover, almost all studied plants could be utilized for the phytoextraction of mentioned HMs. In future, the present study can help in the implementation of public policies to ensure sustainability and developmental activities in contaminated sites. Based on these results, it is concluded that there is a dire need of monitoring solid waste dumpsites due to various types of potential risks associated with the contamination of HMs. Moreover, to minimize the potential health problems arising from the dumpsite, it is substantive that special attention should be paid to work on sustainable and eco-friendly remedial measures.

In this study, nano-TiO2 sulfonated (STiO2) with 1,3-propanesultone was incorporated into the chitosan matrix for the fabrication of chitosan/STiO2 (C/STiO2) nanocomposite membranes. The grafting of sulfonic acid (–SO3H) groups was confirmed with Fourier transform infrared spectroscopy, thermos-gravimetric analysis and energy-dispersive X-ray spectroscopy. The physicochemical properties such as water uptake, swelling ratio, thermal and mechanical stability, ion exchange capacity and proton conductivity of the as prepared membranes were measured. The proton groups on the surface of TiO2 can form continuous proton conducting pathways along the C/STiO2 interface resulting in the improvement of proton conductivity of C/STiO2 nanocomposite membranes. The nanocomposite membrane with 5 % sulfonated TiO2 showed higher proton conductivity (0.035 S·cm-1) than commercial Nafion-117 membrane (0.033 S·cm-1) due to the strong interfacial interactions between -SO3H group of acid and hydroxyl group of TiO2. Further, the –NH2 groups of chitosan restrict the mobility of chitosan chains to enhance the thermal and mechanical stability of the nanocomposite membranes. These C/STiO2 nanocomposite membranes have promising applications in proton exchange membrane fuel cells.

No abstract