Male-biased sex ratios and vitellogenin induction in zebrafish exposed to effluent water from a Swedish pulp mill.
Juvenile zebrafish (Danio rerio) were exposed to different dilutions (0, 0.67, 2.5, 10, and 50%) of effluent water from a Swedish pulp mill that previously has been reported to be androgenic to fish. Exposure was performed between days 10-38 days post-hatch. Fish were sampled for whole-body vitellogenin concentrations at day 38 post-hatch and for histological examination of gonads at day 60 post-hatch. In fish exposed to the highest concentration of pulp mill effluent, elevated concentrations of vitellogenin were measured. The androgenicity of the pulp mill water was confirmed by the increased number of males recorded at 60 days post-hatch. Image analysis of testes indicated stimulation of spennato genesis. Intersex fish were observed in all exposure groups. An androgenic activity equivalent to 5.6 ng/L dihydroxytestosterone was measured using the yeast androgen screen (YAS) assay. The present study demonstrates that both androgenic and estrogenic effects can be detected when exposing zebrafish during the juvenile period to complex mixtures of chemicals.
Orn
Stefan
S
Department of Biomedical Sciences and Veterinary Public Health, SLU, P O Box 7028, SE-750 07 Uppsala, Sweden. Stefan.Orn@bvf.slu.se
Svenson
Anders
A
Viktor
Tomas
T
Holbech
Henrik
H
Norrgren
Leif
L
D000818:Animals; D004784:Environmental Monitoring / Q000379:methods; D005260:Female; D006066:Gonads / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D010209:Paper; D012744:Sex Ratio; D013548:Sweden; D014819:Vitellogenins / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015027:Zebrafish / Q000254:growth & development* / Q000378:metabolism
D014819:Vitellogenins; D014874:Water Pollutants, Chemical