Assessment of oil contamination from the El Grillo shipwreck in Seydisfjordur, Iceland: implications for aquaculture.

This study evaluates current and historical oil contamination from the El Grillo shipwreck in Seydisfjordur, Iceland, to assess potential risks for planned aquaculture operations. The British oil tanker El Grillo has been lying on the seabed at 30-40 m depth since being sunk during a German attack on 10 February 1944, with ongoing concerns about oil leakage. Sediment and seawater samples are collected along a transect from the wreck and analyzed for polycyclic aromatic hydrocarbons (PAHs), heavy metals, and total organic carbon (TOC). The results indicate that all measured PAH values in both sediment and seawater are below the reference threshold values for environmental concern. PAH compounds in sediment samples decreased with distance from the wreck and exhibited pyrogenic signatures characteristic of burned oil. Heavy metals also show a decreasing trend from the shipwreck, with copper and zinc above threshold levels, but lower than probable effect levels. Cadmium and lead are below the threshold levels at all sampling stations. The findings suggest that there has been ongoing natural breakdown of leaked oil during the 80 years since the attack, and therefore, the proposed fish farming operations in Seydisfjordur would not be adversely affected by contamination from the El Grillo shipwreck.