Abstract
Several species of fish from a freshwater lake downstream a landfill in central Sweden have been found to be exposed to specific endocrine active substances (EAS), possibly able to interact with important functions in the synthesis of steroids and thereby disrupting a normal development of the gonad. A preliminary study of 7 streams and lakes in Norway showed that female perch have a significant reduction in gonad somatic index (GSI) with fish length and weight at one location. This can be an indication of disturbance due to exposure of hormonally active agents over time. Only 2 locations showed significantly difference in GSI and liver somatic index (LSI). Possible explanations can be that the necessary combination between exposure and exposed is exclusive and does not apply in general, or that the effects are masked due to other exposures such as e.g., nutrient, organic or other chemicals, physical or biological loads. The number of sampled locations is, however, too limited to be conclusive. Liver samples are being analyzed for organic pollutants, but these analyses were not ready at the time of publication. A previous study of leachate and sediment samples indicated the presence of several organic pollutants and compounds known to be hormonally active. Investigations of extracts from sediment samples from one of the exposed lake in Sweden showed the presence of both naturally occurring and xenophobic organic compounds. In samples extracted with a base-neutral extraction the compounds 1.1 sulfonyl-bis(4-chlorobenzene) and bis-2-etylhexyl-phtalate were detected. The high lipid affinity of the phtalate correlates with the finding of the compound in the high organic content layer of 20–40 cm in the exposed sediment. Pesticide residues were not found in the samples.
Acknowledgment
This work was supported by the Nordtest organization with project number 1540-01, part 1.