Die Miesmuschel Mytilus edulis als Indikator für die Bleikonzentration in Weserästuar und in der Deutschen Bucht

Common mussels were collected at 13 stations of the Weser Estuary and the German Bight in 3 size catagories: 14 to 16 mm, 21 to 23 mm, 35 to 40 mm shell length. Equal numbers of the 3 groups from each station were analyzed separately for lead concentration by flameless atomic-absorption spectrophotometry. The lead concentration of the soft parts decreases from 6.4 μg/g dry weight 15 km northwest of Bremerhaven to 1.9 μg/g at Helgoland. At the same station, the concentration in small musels is significantly higher than in larger mussels. The lead concentration is exceptionally high in the kidney, quite high in the intestine (with the digestive glands) and in the adductor muscle, and rather low in the foot, gills, and mantle with gonads. Unpublished results of my laboratory experiments reveal that mussels directly reflect the actual lead concentration of their environment. The observed gradient in lead contents of M. edulis in the Weser Estuary can thus be explained by the dilution of the highly lead-polluted river water by the sea water of the German Bight. With this physiological property, M. elulis is, therefore, highly suitable as an indicator organism for lead, and possibly other heavy metal pollutants.