Application of Lemna gibba L. and a bio-based aerogel for the removal of metal(loid)s from stream waters near three gold deposits in northwestern Iran

Abstract

Abstract Mining activities can be regarded as one of the main reasons for heavy metals pollution in the environment. In the present study, the capability of duckweed (Lemna gibba L.) and a modified cellulose aerogel, in removing of some metal(loid)s from stream waters near three main gold deposits in the Northwestern Iran was evaluated. The amount of metal(loid)s in water samples and the plant was determined by inductively coupled plasma-mass spectroscopy (ICP-MS). It was found that using plant and aerogel led to the significant reduction of the metal(loid)s concentration in water samples and the performance of the bio-based aerogel in metal remediation was more efficient. Simultaneous use of plant and the aerogel (P+A) for the removal of As, Pb and Cu from the most polluted water sample (S1) was led to the statistically significant increase of removal efficiency (near to 18%, 42% and 63%, respectively), as compared to the use of the aerogel alone. Duckweed could accumulate the metal(loid)s in its body a few hundred times in comparison to the water samples. Photosynthetic pigments and malondialdehyde contents, as well as antioxidant activities in the plant were increased by the enhancement of the amount of the metal(loid)s concentration in treated waters; so, the plant might create tolerable conditions by the induction of its defense system after treatment by the stream waters of the mining areas.