Natural and anthropogenic sources of extractable organic matter in sediments from the coastal zone of the Arabian Gulf in Saudi Arabia

Abstract

Surface sediment samples from the Arabian Gulf coast of Saudi Arabia were collected by Van Veen grab sampler to identify the characteristics, distribution, levels, and to discriminate between natural and anthropogenic sources of the total extractable organic matter (TEOM). The dried and sieved sediments were extracted with a dichloromethane/methanol mixture for analysis by gas chromatographymass spectrometry. The TEOM included n-alkanes (353.9±283.8 ng.g −1 ), n-alkanols (283.2±296.1 ng.g −1 ), fatty acid methyl esters (245.2±353.7 ng.g −1 ), hopanes (100.7±158.2 ng.g −1 ), steranes (58.5±96.3 ng.g −1 ), triterpenoids (18.9±21.1 ng.g −1 ), steroids (15.3±17.0 ng.g −1 ), polycyclic aromatic hydrocarbons (PAHs) (0.48±1.19 ng.g −1 ), as well as an unresolved complex mixture (UCM =1633±3151 ng.g −1 ) and petrochemicals (343.1±424.2 ng.g −1 ). The major sources of these TEOM compound groups were anthropogenic (petroleum and petrochemical) and natural (lipids from higher plants, marine material, and microbiota) inputs. Anthropogenic contaminants from petroleum products ranged from 46.6-85.6% of the TEOM, whereas petrochemicals varied from 10.7-40.6%. Biogenic in ux from terrestrial vegetation ranged from 5.7-19.3%, and marine biotic sources varied from 11.1-37.5%. The continuous accumulation of anthropogenic contaminants will ultimately affect the critical habitats of this marine coastal region. This provides a basis for further studies to understand human and developmental activities on delivery, deposition processes, distribution, and biogeochemical alteration of organic matter in the coastal zones of the Arabian Gulf. Such studies are important for sustainable development and protection of these key regional habitats.

Natural aliphatic lipids and sterols in sediments from Obhur Lagoon, Red Sea coast of Saudi Arabia: Concentrations, spatial distributions, and sources

“…Most of these sediment samples had a C max at C 31 (Table1), indicating a contribution from terrestrial plant waxes of grassy flora(Eglinton and Hamilton, 1967;Simoneit, 1978;Cox et al, 1982;Hatcher et al, 1982;Ficken et al, 2000;Zhang et al, 2006). This C max of n-alkane was also observed in the Arabian Gulf sediments(Rushdi et al, 2010(Rushdi et al, , 2022, showing that plant waxes of tropical vegetation have a high C max…”

“…The carbon preference index of n-alkane values (CPI (o/e) = total Ci (odd) / total Ci (even) , Mazurek and Simoneit, 1984) for the entire varied from 0.8 to 2.7 (x = 2.0), 1.0 to 7.0 (x = 2.5), and 1.1 to (2.3 (x = 1.5) in sediments from Z I, Z II, and Z III, respectively (Table SM1). These values indicated a mixture of input from natural (e.g., terrestrial plants, marine algae, bacteria) sources and petroleum residues (Rushdi et al, 2022).…”

Possible Future Risks of Pollution Consequent to the Expansion of Oil and Gas Operations in Qatar

“…Thus, algae can be used as phytoremediators to clean waters contaminated with various types of heavy metals and petroleum hydrocarbons in various parts of the world, including oceans and lakes (Paleologos, Al Nahyan, & Farouk, 2018;Khazali and Taghavi, 2021;Rushdi et al, 2021). Algae have been recognized as important living groups to control metal concentrations in lakes, ponds, rivers, oceans, and wetland habitats.…”

“…The first, is spills of petroleum hydrocarbons and other oil residues that are deposited in the intertidal zone as a result of wars, military exercises, and transport (Fowler, 1993;Al-Saad and Salman, 2012;Rajendran et al, 2021). The second, is anthropogenic and industrial activities near the shores (Rushdi et al, 2017;Khazali and Taghavi, 2021;Rushdi et al, 2021). The last one is discharge of brine after desalination of seawater (Paleologos et al, 2018;Hosseini et al, 2021).…”

Occurrence, Distribution, and Sources of Aliphatic and Cyclic Hydrocarbons in Sediments from Two Different Lagoons along the Red Sea Coast of Saudi Arabia

“…Moreover, oil pollution in the coastal environment of Saudi Arabia's Red Sea might occur by sewage discharge from offshore platforms, ship traffic, tour boats, ferries, private yachts, leisure activities, and littering [43][44][45]. Additionally, petroleum-related products can be introduced into the coastal environment through the deposition of transported atmospheric particulate matter, resuspension of soil by winds, and seasonal runoff of streams and floods [46,47].…”