Evaluation of Azolla filiculoides potential in pyrene and phenanthrene accumulation and phytoremediation in contaminated waters

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are a serious threat to the health of the environment. This study investigated the potential of Azolla filiculoides for the uptake, accumulation, and biodegradation of phenanthrene and pyrene. A- filiculoides plants were treated with 10 and 30 mg L⁻¹ concentrations of phenanthrene and pyrene for the experimental duration of ten days. Phenanthrene and pyrene concentrations were measured using the high-performance liquid chromatography (HPLC) technique. Identification of the intermediate by-products resulting from the biological degradation of PAHs was performed by gas chromatography-mass spectrometry (GC/MS). The quantities of phenanthrene and pyrene in the ten-day treatments with 10 and 30 mg L⁻¹ were 0.007 and 0.011 mg g⁻¹ FW, and 0.048 and 0.079 mg g⁻¹ FW, respectively. The growth parameters in the plants such as fresh weight, dry weight and RFN as well as the content of photosynthetic pigment of the plant decreased significantly compared to the control sample (p < 0.05). Ten compounds were identified from the plant tissue during the decomposition of pyrene and phenanthrene, and none of the PAHs were identified in the aquatic environment. Therefore, the use of A-filiculoides for phytoremediation of water resources contaminated with PAHs is an effective and promising method.

STATEMENT OF NOVELTY

This study estimated the efficiency of Azolla filiculoides phytoremediation in the uptake, accumulation and biodegradation of phenanthrene and pyrene in polluted waters as a total of 100%. High accumulation of pyrene and phenanthrene in the plant tissue decreased plant growth and the number of photosynthetic pigments. GC-MS analysis, identified ten by-products resulting from the degradation of pyrene and phenanthrene in A-filiculoides plant tissue. HPLC analysis showed that there are no substances of PAHs in the water environment.

Keywords:

• Aromatic hydrocarbons
• Azolla filiculoides
• Bioaccumulation
• Biosorption
• PAHs
• Phytoremediation

Acknowledgement

This research with Ethics Code IR.NIMAD.REC.1398.309 was supported by Elite Researcher Grant Committee from the National Institute for Medical Research Development (NIMAD), Tehran, Iran. The authors thank the cooperation of the Department of Environmental Health Engineering, Faculty of Health, Health Sciences Research Center, and the Student Research Committee of the Research Deputy of Mazandaran University of Medical Sciences, Sari, Iran. Also, would like to thank the guidance by Dr. Abbas Gholipour, Associated professor of Biology.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was funded by the Grand Committee of Elite Researchers under the award number (IR.NIMAD.REC.1398.309) of the National Institute of Medical Research Development of Iran (NIMAD).