Assessing the ecological risks from hydrocarbons in the marine coastal sediments of Jeddah, Red Sea.

The Red Sea is a unique aquatic environment, and it is host to highly biodiverse marine organisms. This body of water occurs along the western side of Saudi Arabia, which is one of the largest producers of crude oil in the world. Thus, the sea's contamination by oil pollutants could pose a large problem and is a major concern in the region. The samples were analyzed to determine their polycyclic aromatic hydrocarbon (PAH) speciation and assess the associated ecological risk to the coastal environment of the Red Sea. The geographical distribution of the 16 total PAHs by concentration (range and average values in ng g-1 dry wt.) occurred in the following order: the northern region (1169.8 to 2742.0; 2083) < the southern region (1971.4 to 3003.4; 2493) < the middle region (2222.0 to 2930.6; 2599). The PAHs with two, three, four, five, and six rings make up 7.0%, 13.0%, 70.0%, and 10.0% of the total PAHs, respectively. The diagnostic ratio results showed that the PAHs may be attributed to petrogenic and pyrogenic sources. The PAH concentrations were considered toxic when their levels ranged from 119 to 491 ng toxic equivalent g-1 dry wt. According to the mean range of PAH effects (the mean effect range median quotient values), the ecological risk posted by the investigated sediments was lower than 0.1, denoting a toxicity effect with a probability of 11%. The analysis of PAHs highlighted that the sampling sites were low priority sites, and their PAHs may not cause acute biological damage.