Hormonelike effects of humic substances on fish, amphibians, and invertebrates.
Humic substances comprise the majority of organic matter in freshwater ecosystems and were thought to be inert or refractory, except for photolytic degradation. However, evidence is increasing that humic substances interact with aquatic organisms similarly to weak anthropogenic chemicals with nonspecific and specific effects. One specific effect is a hormonelike effect, namely, modulation of the number of offspring, which was first described with the nematode Caenorhabditis elegans. Yet a hormonelike effect is not restricted to only the nematode. With the ornamental swordtail fish, Xiphophorus helleri, and the South African clawed frog, Xenopus laevis, we present phenomenological evidence that slight feminization occurred when these vertebrate species were exposed to a synthetic humic substance, a condensation product of polyphenols. The slight feminization was dose dependent.
Leibniz Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587 Berlin, Germany. stein@igb-berlin.de
Christian E W
CE
Steinberg
Sebastian
S
Höss
Werner
W
Kloas
Ilka
I
Lutz
Thomas
T
Meinelt
Stephan
S
Pflugmacher
Claudia
C
Wiegand
D000818:Animals; D001578:Benzopyrans / Q000633:toxicity; D017173:Caenorhabditis elegans / Q000502:physiology*; D003532:Cyprinodontiformes / Q000502:physiology*; D005262:Feminization / Q000209:etiology; D005419:Flavonoids / Q000138:chemical synthesis / Q000633:toxicity; D006812:Humic Substances / Q000633:toxicity*; D008297:Male; D010063:Ovum / Q000187:drug effects; D010636:Phenols / Q000138:chemical synthesis / Q000633:toxicity; D059808:Polyphenols; D012098:Reproduction / Q000187:drug effects*; D012744:Sex Ratio; D014982:Xenopus laevis / Q000502:physiology*
D001578:Benzopyrans; D005419:Flavonoids; D006812:Humic Substances; D010636:Phenols; D059808:Polyphenols; C005023:fulvic acid