Effects of methoprene, nonylphenol and estrone on the vitellogenin production of opossum shrimp
A number of anthropogenic chemicals are known to have the potential to disrupt the vitellogenin production in vertebrates. Male fish e.g. are known to produce this protein when exposed to xeno-estrogens (case study in eels).Little is know however about the potential effects of such endocrine disrupting compounds on the vitellin production of invertebrates.
Content of the study
Within the framework of the ENDIS-RISK project a high exposure of the Scheldt estuary opossum shrimp population to endocrine disrupting substances has been detected, including several priority substances. This study investigated the effects of 3 substances, known to disrupt the endocrine system of fishes, on the vitellogenin production of opossum shrimp. These substances were methoprene, nonylphenol and estrone. Estrone is a natural female sex hormone (an estrogen), which occurs in the Scheldt estuary at concentrations up to 8ng/l.
Results of the study
Lethal concentrations for nonylphenol, methoprene and estrone were found to be 590ug/l, 320µg/l and above 10mg/l respectively. Concentrations above 0.01 µg/l and 1 µg/l of methoprene and estrone respectively resulted in a reduction of the vitellogenin content of female opossum shrimp. Concentrations of 0.01 µg/l nonylfenol did show a significant increase in the femal vitellogenin content, while the vitellogenin content of females exposed to higher concentrations of nonylfenol, 1 µg/l and 100 µg/l, didn't increase. The measured effect concentrations for nonylphenol and methoprene are above the environmental levels in the Scheldt estuary and might therefore pose problems for these and other crustaceans. These concentrations however are higher than those which cause problems for egg laying marine vertebrates (such as fishes).