Assessment of TPH and nickel contents associated with tolerant native plants in petroleum-polluted area of Gachsaran, Iran

The main aim of this study is to identify total petroleum hydrocarbons (TPHs) and nickel contents in soil as well as to evaluate the phytoremediation potential of native petroleum-resistant plants of Pazanan-E-Gachsaran (Iran). Firstly, soil samples were taken from depth of 0–30 cm in three ranges (0–500, 500–1000, and 1000–1500 m) from the center of pollution area of soil to outer part, and plant samples were taken by a linear transect from the same place. According to the results, there are 24 frequent species from 12 families in this region including Poaceae (25%), Asteraceae (20.83%), and Chenopodiaceae (12.50%). The results of initial soil test revealed that more distance from the core, leads to more decrease in the content of TPHs. Comparing total nickel content of soil showed a reduction trend from span (0–500 m) to 3 (1000–1500 m). The maximum nickel was found in the roots of Stipagrostis plumosa while lowest amount was observed in Cynodon dactylon. According to the frequency of Sipagrostis plumosa, Calotropis procera, and Sinapis arvensis, and their ability to resist in improper circumstances of the study area, these species were recognized as tolerant species that can be developed to decrease soil contamination of Pazanan. Therefore, they can be an appropriate choice for the phytoremediation of TPHs and nickel-contaminated soils.