Morphological effects of Bisphenol-A on the early life stages of medaka (Oryzias latipes)

Bisphenol-A (BPA), a widely used polycarbonate plasticizer, has been of concern because it has been shown to leach out of plastics and other epoxy products. Primary sources of environmental releases are expected to be from BPA and epoxy manufacturing facilities. Although environmental concentrations may be limited, little is known about the effects of this compound on fish, particularly during their most sensitive early life stages. A pilot study exposing newly hatched medaka to 200 μg BPA/l for 96 h showed to be non-lethal. In addition, medaka embryos were exposed beginning at 5 h post-fertilization, for 9 days at 25°C, to concentrations of 20 or 200 μg BPA/l (24 h static renewal). Embryos were monitored daily for development and gross abnormalities. Embryos exposed to 200 μg BPA/l did not exhibit abnormalities until after day 4. However, between days 4 and 8 the severity index (SI) score of embryos was significantly greater than those exposed to lesser concentrations. By day 9, SI scores were not statistically different among treatments. BPA caused transient embryonic deformities in medaka at environmentally relevant concentrations.