Impairment of green-lipped mussel (Perna canaliculus) physiology by waterborne cadmium: Relationship to tissue bioaccumulation and effect of exposure duration

Laboratory studies were performed to assess the impact of acute and subchronic cadmium (Cd) exposure on the green-lipped mussel, Perna canaliculus. A 96h median lethal concentration (LC₅₀) value of 8160μgL^-1 was determined, characterising this species as relatively tolerant to Cd exposure. Acute (96h; at 2000 and 4000μgCdL^-1) and subchronic (28d; at 200 and 2000μgCdL^-1) waterborne exposures were then conducted to investigate the impact of Cd exposure on physiological responses (e.g. clearance (feeding) rate, absorption efficiency, oxygen uptake, ammonia production, oxygen to nitrogen ratio, scope for growth) and tissue Cd accumulation. Cd accumulation in digestive gland showed saturation with respect to increasing exposure concentration, while the gill tissue Cd accumulation followed a positive linear relationship with Cd exposure level. Clearance rates declined during both acute and subchronic exposures at levels of 2000μgCdL^-1 or higher. Impairments of clearance rates were strongly correlated with tissue Cd accumulation. Coupled with their importance as a food source, and their wide coastal distribution, these data suggests that P. canaliculus may be a species useful as an indicator species for trace metal pollution in coastal environments.