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Title: Endocrine Modulating Effects of Wastewater Treatment Works Effluents: 'Sensitive Windows' for inducing germ-cell intersex in the Roach (Rutilus rutilus)
Author: C. Tyler
Author: K. Liney
Author: S. Jobling
Author: Agnecy: Bristol Environment
Document Type: Monograph
Annotation: Environment Agency Project ID:EAPRJOUT_1532, Representation ID: 531, Object ID: 2669
The objective of this project was to assess the effects of exposure of fish to waste water treatment works (WwTW) effluents from two different sewage treatment works during the two life periods believed to be the most vulnerable to disruption of sexual development. The percentage of trade influent entering the two treatment works studied was 6% at site A and 24% at site B. The population equivalents also differed between the sites and were 137,000 at site A and 312,700 at site B. Fertilised eggs or adult fish were exposed to a graded concentration of the effluents (from 0% effluent to 100% effluent) diluted with river water or tap water until 300 days after hatching (in the early life stage experiments) or for a period of 2 or 4 months in the two adult experiments. Biological samples were taken at 50, 100, 200 and 300 days after hatching (in the juvenile fish study) and at the end of each trial (in the adult trials). In addition, in the early life stage experiment, a sample of fish from each treatment was transferred to clean dechlorinated tap water after only 60 days exposure and reared until they were 300 days old. When taken together, the results of these three experiments suggest that exposure of fish to WwTW effluents for relatively long periods during certain parts of the life cycle can induce some (vitellogenin and oviducts), but not all (eggs in testes), of the characteristics of intersex seen in wild fish that reside in rivers downstream from effluent discharge points. The general health effects of exposure of young fish to treated sewage effluents were also examined and the utility of vitellogenin as a biomarker for these general health effects was examined. Vitellogenin was detected in body tissues including the liver (where it is synthesised), the kidneys and in the gonads (ovaries and testes) of the exposed fish and was most apparent in the fish exposed to the effluent at site A. Indeed, more detailed examination of the kidneys showed that there was an increase in the diameter of the kidney tubules and in the number of glomeruli in the kidneys with increased dose of effluent in fish at both of the study sites. Moreover, exposure to the highest concentration of effluent at site B, induced development of new nephrons by the kidneys of the exposed fish, reflecting the increased demand for filtration and removal of inappropriately produced vitellogenin and of pollutants. In some cases, these effects were retained when fish were transferred to clean water for 240 days following exposure, indicating a long-term effect of the effluent on the kidney development. The significance of the changes in the kidney is not known and they may reflect an acclimation to the effluent. There were no signs of overt kidney damage as a consequence of the effluent exposures.
Publisher: Environment Agency
Subject Keywords: RiversEndocrinological functionsFishesEnvironmental monitoringEffluentsAdultsJuveniles
Taxonomic Keywords: Rutilus rutilus
Extent: 117
Total file downloads: 260

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