Evidence of Exposure of Fish to Produced Water at Three Offshore Facilities, North West Shelf, Australia

Abstract

In Western Australia, the discharge of produced water (PW) by the offshore petroleum production facilities is acceptable under specific conditions. Little is known on the effects of PW discharge on the health of marine organisms attracted to the submerged structures. Three offshore facilities have been selected for studying the impact of exposure to PW discharge on fish health, as measured by a suite of biomarkers of fish health. Physiological indices (liver somatic index, condition factor) as well as biochemical markers of exposure (EROD activity, biliary metabolites) and of effect (DNA damage, stress proteins) have been assessed on three different fish species captured in the vicinity of the facilities. Condition factor was slightly reduced at one site only, but liver somatic index was elevated in fish captured at two of the three locations. EROD activity and DNA damage levels were high only at one facility discharging high volumes of PW. Naphthalene and pyrene biliary metabolites were detected at significant levels at all locations. Stress proteins HSP70 were also elevated at all locations. The results suggest that while the chemical characteristics of PW are important, consideration of the loading (concentration × volume) of PW is crucial in assessing environmental effects and risks of PW discharge.