Toxicity assays of marine sediments from western Venezuela

Abstract

Refineries are one of the main sources of coastal marine pollution worldwide. In this study, the toxicity of sediments potentially impacted by the Paraguaná Refinery Complex on the west coast of Venezuela was evaluated using chronic toxicity assays. This toxicity was determined by exposing larvae of the shrimp Litopenaeus vannamei and the polychaete Scolelepis texana to bioassays during 28 and 10 days, respectively. Both bioassays indicated that the sediments surrounding the refinery are highly toxic, compared to sediments from the same region farther from the refinery and sediments from a control zone. The sediments surrounding the refinery had relatively high concentrations of total petroleum hydrocarbons (>10,000 ppm); of heavy metals such as chrome, nickel, and zinc; and of polycyclic aromatic hydrocarbons (ΣPAHs > 1000 ppb). This study forms part of the first environmental ecological risk assessment done in Venezuela. The high toxicity of the sediments close to one of the largest refinery complexes in the world should serve as a warning of the possible impacts on benthic and planktonic communities that live in the environs of refineries in coastal marine environments.

Keywords

• toxicity bioassays
• hydrocarbons
• metals
• oil refinery.