Work

Impact of offshore energy activities on trace elements content and mobility in marine sediments

Year: 2024

Type: article

Abstract: The offshore oilfields in the North Sea area are increasingly employed for projects beyond oil production, like carbon capture and storage (CCS). Still, the fossil fuel production from mature fields is significant. It has raised environmental concerns associated with discharging produced waters (PW) and drilling mud into the sea. These discharges, which may be highly saline and contain production chemicals and varying levels of metals and particulates, sink toward the seafloor due to their density and release depth. This study investigates the impact of these discharges on seafloor sediments around two smaller Danish oilfields, assesses the mobility of metals within these sediments, and evaluates the environmental status. PW samples were collected at the discharge outlets from the platforms. Sediment cores were taken near two oil platforms and from control sites. Using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and an optimized BCR sequential extraction, we analyzed the composition and distribution of 24 elements in sediment samples. The results revealed significant differences in total concentrations between sediments near the platforms and those from distant locations and stratigraphically older samples, with elevated levels of Ba, Sn, Zn, and other metals near the platforms. Sediment quality indices showed considerable enrichment and geo-accumulation of toxic metals, particularly at one of the platform sites. However, cumulative indices did not display significant pollution anomalies. Therefore, our findings suggest that oil extraction activities may increase the availability of toxic metals in nearby sediments, potentially impacting marine ecosystems.

Source: Marine Pollution Bulletin

DOI: 10.1016/j.marpolbul.2024.117491

Authors: Neri Bonciani, Bodil W. Lauridsen, Rasmus Jakobsen, Karen L. Feilberg

Institutions: Technical University of Denmark, Geological Survey of Denmark and Greenland

Language: English

Topic: Heavy metals in environment

Subfield: Pollution

Field: Environmental Science

Domain: Physical Sciences

SDG: Life below water

Open Access status: hybrid

Estimated APC paid: $3,630