Distribution and Sources of Hydrocarbon Compounds in Sediments from Obhur Lagoon: Red Sea Coast of Saudi Arabia

Abstract

Surface sediment samples from Obhur Lagoon on the Red Sea coast of Saudi Arabia were collected and analyzed to determine the levels, distribution and sources of hydrocarbon compounds. The sediments were collected using a Van Veen grab sampler, dried, extracted with a mixture of dichloromethane/methanol, and analyzed by gas chromatography-mass spectrometry. The major hydrocarbons of these lipid extracts included n-alkanes (6-645 ng g −1 ), methyl n-alkanoates (1-311 ng g −1 ), hopanes (3-219 ng g −1 ), steranes (5-258 ng g −1 ), phthalates (4-201 ng g −1 ), and an unresolved complex mixture (UCM) (0-4571 lg g −1 ). Anthropogenic petroleum products and plasticizers were the main sources of these hydrocarbons, with lesser amounts from biogenic sources, including natural waxes of terrestrial higher plants and marine microbial detritus. The estimated anthropogenic inputs of the total lipid hydrocarbons for all sediments ranged from 14 to 98% for petroleum products and from 2 to 18% for plasticizers, whereas biogenic inputs ranged from 0 to 10.7% for terrestrial higher plant waxes and from 0 to 68.5% for marine microbial detritus. The presence and inputs of petroleum residues and plasticizers to the coastal sediments of the lagoon likely affect the marine ecosystems and associated species groups that use the lagoon as a coastal nursery and spawning area.

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

“…The TEOM levels indicated that lipid compounds were present in considerable amounts, as compared to petroliferous contaminants reported recently (Rushdi et al, 2019;. They included n-alkanes, fatty acid methyl esters, n-alkanols, sterols, biomarkers (mainly hopanes and steranes), plasticizers, and an unresolved complex mixture (UCM) of highly branched and cyclic hydrocarbons.…”

“…Thus, these activities affect the natural habitats of the lagoon and the sedimentary OM content and distribution. The main recent studies have focused on organic contaminants (Alansari, 2019;Ibrahim and Al-Farawati, 2023;Rasiq et al, 2018;Rushdi et al, 2019;Turki and Mudarris 2008), but no study has investigated the types and sources of natural OM input in the lagoon.…”

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

“…The lagoon is a vital habitat for various bird species and aquatic life. It is known for its picturesque landscapes, with extensive seagrass beds and mangroves that provide crucial breeding and forging grounds for a multitude of bird species, including flamingos and herons [50]. The lagoon serves as a refuge for marine life, supporting an array of fish species and diverse wildlife, making it a site of great environmental and recreational value to the Kingdom of Saudi Arabia.…”

“…In Saudi Arabia, the coastal development of the Red Sea is part of the Saudi Giga-Project (The Red Sea Project, Vision 2030); however, such activities might disrupt the ecosystems and introduce the pollution to marine life [48]. Previous studies have shown that coastal sediments from Obhur lagoon north of Jeddah city in the Red Sea are contaminated with diverse groups of hydrocarbons from petroleum products and plasticizers from littering [49]. However, there is no information about the characteristics, sources, and levels of sedimentary organic matter in other lagoons along the Red Sea coast of Saudi Arabia.…”