In the short term (days to weeks), during the pollution's spreading phase, the potentially dominating effects are oiling and toxicity. These effects can last a few weeks after the pollutant ceases to arrive onshore. They concern in particular benthic invertebrates with limited or no mobility in loose or rocky substrates: echinoderms, crustaceans, bivalves, gastropods and polychaete in particular. Species are affected in many ways, according to their sensitivity to hydrocarbons. In the event of acute toxicity, beachings of dead shellfish or sea urchins may occur. In the water column, plankton can be locally and temporarily affected. This can concern fish eggs and larvae and crustacean, in particular tuna eggs, with the risk of incidence on the restocking that year. In the medium and long term (weeks to months), the physical effect of coating and oiling of the species of the foreshore, leading to the detachment of seashells, especially limpets, is sometimes followed by a proliferation of green algae due to a decrease in consumption by marine populations.
As for coastal benthic populations, pollution by hydrocarbons can cause a localised loss of the most sensitive species, to the benefit of opportunistic species, potentially leading to the disappearance of certain populations. These populations will only be re-established with the gradual return of the species affected.
The risks for seabirds were moderate, as the migration season was over. As for mammals, the lack of data means that no significant impact can be predicted. However the presence of Mediterranean monk seals, a listed endangered species, in the Palm Island region should be noted. Four species of turtles, including the green turtle, an endangered species, reproduce on the Lebanese coasts. Reproduction sites exist in the Tyr and Palm Island reserves. An impact risk exists, due to the oiling of beaches during the egg hatching period, the eggs being laid from May to August and hatching 1 to 2 months later.
In terms of human activities, the presence of fuel on the beaches and in the coastal waters led to a ban on swimming in the sea and beach activities. The risk of nets being oiled and of bringing in oiled products meant that coastal fishing also had to cease. For these activities to be resumed, peace will have to be restored, life return to normal and the sites cleaned up.
In the absence of accurate information on the extent of beachings and the weathering of the pollutant, it would be risky to make statements other than these general considerations. The Mediterranean is not in danger. However, this pollution is serious. It will require several months of difficult, costly clean-up work, a heavy task, all the more so in a country in turmoil.