Application of some aquatic plants as bio-indicators for petroleum hydrocarbon compounds in Um Alnaaj Marshes, Iraq

Petroleum hydrocarbon compounds are one pollutant that contributes to water pollution in Um Alnaaj Marshes in Iraq. The present study aimed to estimate the role of some aquatic plant species in the accumulation of petroleum hydrocarbon compounds. Four plant species viz. Typha domingensis, Phragmites australis, Azolla filiculoides, and Hydrilla verticillatafrom) were collected from Um Alnaaj marshes in southern Iraq and used as a bioindicator for petroleum hydrocarbon compounds. The results showed that Total Petroleum Hydrocarbons (TPHs) concentrations ranged from 21.3 to 53.9 µg/g, dw in A. filiculoides and T. domingensis, respectively. In addition, the levels of total PAHs were 2376.501, 1127.139, 541.17, and 19.062 ng/g, dw in T. domingensis, H. verticillatafrom, A. filiculoides, and P. australis, respectively. Higher molecular weight PAHs were more than lower molecular weight PAHs in all plants studied. The results also revealed that the origin of PAHs in the studied plants according to LPAHs/ HPAHs ratio and Fluo/ Pyr ratio was a mix of pyrogenic and petrogenic. Furthermore, the results showed that the sources of n-alkanes, according to Carbon Preference Index (CPI) ratios, were biogenic in all plants except P. australis, which was anthropogenic. However, the Pristine /Phytane ratio was less than one in all studied plants. A high accumulation of hydrocarbon compounds was observed in studied plants, which indicated the possibility of using aquatic plants as a bio-indicator for petroleum hydrocarbon pollutants in the marshes of Iraq.