Forensic investigation of aliphatic hydrocarbons in the sediments from selected mangrove ecosystems in the west coast of Peninsular Malaysia

Aliphatic and polycyclic aromatic hydrocarbons risk assessment in coastal water and sediments of Khark Island, SW Iran

“…On the contrary, due to high hydrophobic properties of AHs, the composition of n-alkanes in sediments showed very variable pattern such that the total concentration of the n-alkanes (∑ C 10 -C 35 ) ranged from 19.75 to 49.25 μg/g (mean 25.31 μg/g) ( Table 4). In comparison with the results obtained in other studies, ∑ n-alkanes in sediments of Khark Island were as high as in the sediments at the coast of Aliağa, Turkey (Neser et al, 2012), much higher than in sediments at Bohai Sea (Li et al, 2015d;Wang et al, 2015), Sergipe-Alagoas Basin, Brazil (Lourenço et al, 2013) and much lower than sediments of the west coast of Peninsular Malaysia (Vaezzadeh et al, 2015), Ushuaia Bay, Argentina (Commendatore et al, 2012). ∑ n-alkanes showed moderate relationship with clay sized particles and TOC (R 2 = 0.44 and R 2 = 0.51, respectively, P b 0.05, n = 8).…”

“…The CPI is calculated based on both high molecular weight (HMW) and low molecular weight (LMW) n-alkanes Li et al, 2015d Where, TAR is terrigenous/aquatic ratio and NAR is Natural nalkanes ratio, the details of which are given in (Commendatore et al, 2012;Kucuksezgin et al, 2012;Silva et al, 2013;Tran et al, 1997;Vaezzadeh et al, 2015;Wang et al, 2015). …”

“…The calculated LMW/HMW ratio ranged from 0.73 to 1.33 μg/g. The LMW/HMW ratio near unity imply that the n-alkanes are mainly from the planktonic and petroleum sources, while the LMW/HMW ratio much lower than 1 suggest that the n-alkanes are produced by marine organisms, vascular plants and sedimentary bacteria (Neser et al, 2012;Tran et al, 1997;Vaezzadeh et al, 2015). Hence, it may be concluded that the presence of n-alkanes in coastal sediments of Khark Island mainly originated from plankton and petroleum contaminations.…”

“…The most abundant n-alkane, is normally centered around C 18 for samples highly contaminated with petroleum (Tran et al, 1997). Moreover, the presence of n-C 15 , n-C 17 and n-C 19 reveals marine biogenic origin (especially algae and plankton communities), while presence of high molecular weights and odd carbon number like n-C 31 , n-C 33 and n-C 35 indicates the existence of the terrestrial hydrocarbons Kucuksezgin et al, 2012;Silva et al, 2013;Vaezzadeh et al, 2015). Furthermore, existence of a complete sequence of long and short chain n-alkanes reveals AHs associated with petrogenic sources, while long molecular chains with an odd number of carbons denote AHs from vascular plants (Lourenço et al, 2013).…”

“…The carbon preference index (CPI) is the most common index for determination of the sources of AHs (Commendatore et al, 2012;Li et al, 2015d;Vaezzadeh et al, 2015;Wang et al, 2015). The calculated LMW/HMW ratio ranged from 0.73 to 1.33 μg/g.…”