Environmental harm assessment of a wastewater discharge from Hammerfest LNG: A study with biomarkers in mussels (Mytilus sp.) and Atlantic cod (Gadus morhua)

Biologically treated wastewater (WW) from the Hammerfest LNG (liquefied natural gas) plant is discharged to the sea. A study using biomarkers in mussels and Atlantic cod was performed to examine whether this discharge meets a zero harmful emission requirement. Caging of mussels close to the outfall and exposure of mussels and fish to WW in the laboratory were conducted, and a suite of contaminant responsive markers was assessed in exposed animals. In mussels the markers included chemical contaminant levels, haemocyte lysosomal instability and nucleus integrity, cellular energy allocation, digestive gland and gonad histopathology and shell-opening behaviour. In fish, biliary PAH metabolites and gill histopathology biomarkers were measured. A consistent cause-effect relationship between WW treatments and markers measured in test animals was not found. The results therefore indicate that the WW emission is unlikely to represent a significant stress factor for the local marine environment under the conditions studied.

► The ecotoxicity of a LNG plant wastewater (WW) was assessed in mussels and fish. ► Test animals were exposed by in situ caging (mussels) and laboratory exposures. ► A suite of contaminant responsive markers were measured in the test animals. ► Significant responses were not observed in WW exposed test animals. ► The WW discharge is most likely not harmful for the local marine environment.