Phytoremediation of BTEX from indoor air by Hyrcanian plants

Background: Phytoremediation is one of the available and simple techniques for removing benzene, toluene, ethylbenzene, and xylene (BTEX) from indoor air. This study aimed to evaluate phytoremediation of low concentrations of BTEX by Hyrcanian plants including Ruscus hyrcanus and Danae racemosa. Methods: The test chamber was used to evaluate the removal of BTEX. Benzene, toluene, ethylbenzene, and xylene were injected into the chamber using Gastight syringes (Hamilton) to generate the concentration of 10 (benzene), 20 (toluene), 20 (ethylbenzene), and 50 (xylene) μL/L Results: Ruscus hyrcanus was able to remove BTEX (10, 20, 20, and 50 μL/L) from air after 3 days. D. racemosa could uptake BTEX (10, 20, 20, and 50 μL/L) from air after 4 days. Removal efficiency was calculated based on leaf area and volume of the chamber. R. hyrcanus showed the highest removal efficiency ranged from 8.5075 mg/m3/h.cm2 for benzene to 86.66 mg/m3/h.cm2 for xylene. The increase in BTEX phytoremediation was assessed after repeated exposures. A significant phytoremediation efficiency was obtained after the third injection of BTEX to the chamber. Afterwards, the effects of BTEX on anatomical and morphological structure of plants were studied. The results of Photomicrography showed that tissue structures of leaves and stems changed. Study of D. racemosa and R. hyrcanus stems showed that vascular bundles also changed. The development of crystal in vacuole of spongy parenchyma was the main anatomical change of R. hyrcanus and D. racemose compared to the control samples. Conclusion: It can be concluded that R. hyrcanus and D. racemosa can be used for phytoremediation of indoor air pollution.