Monitoring the nearshore marine environment in Vleesbaai

The Petroleum Oil and Gas Corporation of South Africa (Pty) Ltd, (PetroSA), operates a Gas-to-Liquids refinery in Mossel Bay producing petroleum products. Since 1991/1992, effluent from this refinery has been discharged into the coastal zone through a subtidal pipeline extending 1276 m offshore to a depth of 22m. In 2011, PetroSA commissioned SAEON Egagasini to develop a comprehensive monitoring program for a period of at least 3 years to assess for potential impacts of effluent discharge on the marine environment. SAEON, in collaboration with the CSIR, developed and implemented an annual environmental monitoring program that aims to assess the potential impacts of effluent released from the PetroSA pipeline on benthic marine communities and habitats. Annual sampling efforts include the water column properties, sediment properties and benthic meiofauna and macrofauna. The intensive study revealed that the surveyed marine environment does not show evidence of heavy pollution effects resulting from the PetroSA effluent. The final report from the three-year monitoring program was released in November 2014 and can be downloaded here. The report recommends that further surveys of the area could be conducted every three years, at the discretion of the regulating authority.