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(495) Toxic refuse dump leachate disrupts the gonad development and steroidogenesis in female perch.
Noaksson, Erik*,1, Linderoth, Maria1, Zebuhr, Yngve1, Gustavsson, Bodil1, Broman, Dag1, Balk, Lennart1, 1 Stockholm University, Institute of Applied Environmental Research, Stockholm, Sweden
ABSTRACT- Swedish refuse dumps are constructed to passively disperse toxic leachate into the environment, thus being potential anthrophogenic point sources. In the leachate-contaminated Lake Molnbyggen, Sweden, we recently observed that 75% of the female perch (Perca fluviatilis) were arrested in a non-reproducing immature stage paralleled by, reduced levels of circulating steroids, lower P450arom activity, decreased gonadosomatic index (GSI), as well as high frequencies of skin lesions and higher EROD activity. To further investigate the endocrine mechanism and critical time-frames for employed reproductive biomarkers, an annual study was conducted on reference and Lake Molnbyggen female perch, applying analysis of steroid hormones by HRGC/HRMS, in addition to liversomatic index (LSI), GSI, and brain P450arom activity measurements. Although skin lesions, such as sores, were less frequent, a very high percentage of non-reproducing immature female perch was still found in Lake Molnbyggen. Even though no significant effect was seen on GSI, a lower LSI was found to be paralleled by lower levels of several steroid hormones, especially androstenedione and testosterone, during the first months of oogenesis in reproducing female perch from Lake Molnbyggen, compared to reference perch. The endocrine mechanism behind the disturbed recruitment of maturing oocytes and the lower, or delayed, steroidogenesis in reproducing Lake Molnbyggen perch, could be interpreted as either an early disruption in the brain-pituitary-gonadal axis, inhibited metabolism of steroids, prior to androstenedione synthesis, or increased metabolism and excretion of steroids. Steroid profiles, combined with sexual maturation data and GSI, constitute powerful and sensitive reproductive biomarkers, providing evidence of adverse effects on gonad development and steroidogenesis in perch by endocrine disrupting substance(s) present in the toxic refuse dump leachate.
Key words: refuse dump, endocrine disruption, steroidogenesis, HRGC/HRMS
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