Heavy metals contamination of river water and sediments in the mangrove forest ecosystems in Bangladesh: A consequence of oil spill incident

Oil spillage is one of the common pollution events global water-soil ecosystems. A comprehensive investigation on heavy metals surface water and sediments was conducted after oil spill incident in Sela River its tributaries Sundarbans mangrove forest ecosystems, Bangladesh. Water sediment samples were collected from preselected sampling points River, elemental (Pb, Cd, Cr, Co, Cu, Ni, Fe, As, Hg, Mn, Zn, Ca, Mg, Na, K) analysis done using atomic absorption spectrometer (AAS). This study revealed that descending order for average concentration studied elements found to be Mg > Co Na Ni K Ca Pb Fe Mn Cr Cd Zn Cu respectively, while As Hg below detection limit (BDL). However, some toxic exceeded permissible set by World Health Organization (WHO) with a respectively. Based quality index (WQI), metal (MPI), (MI), not suitable drinking but may used irrigating agricultural vegetable crops. On other hand, following Several assessment indices: contamination factor (Cf), degree (Cd), modified (mCd), load (PLI), enrichment (EF), geo-accumulation (Igeo) indices followed assess systems area. Considering indices, this river had higher (Cf) values moderate Pb, low K. Among metals, content highest both samples, which confirming insoluble or suspended form, more likely strongly deposited bound water. Principal component correlation analyses suggested sources mainly anthropogenic along geogenic