Comparison of benthic foraminifera and macrofaunal indicators of the impact of oil-based drill mud disposal

► Both macrofauna and foraminifera can be used as bio-indicators of environmental impact. ► There are evident differences between macrofaunal and foraminiferal indices of environmental impact. ► The foraminiferal index FIEI appeared to be more discriminative than the macrofaunal one. ► The FIEI approach applied to macrofaunal data showed a similar sensitivity to that of the index based on foraminifera. ► FIEI will produce a clear bonus to environmental monitoring studies.