Risk Assessment of Nonylphenol using Sex Ratio, Sexual Maturation, Intersex and Lipofuscin Accumulation of the Equilateral Venus Gomphina veneriformis (Bivalvia: Veneridae)

Abstract

Nonylphenol (NP) is an estrogen-mimicking compound or xenoestrogen. This study investigated the effects of nonylphenol on the reproductive status of the equilateral venus Gomphina veneriformis. The experiment lasted 24 weeks, Experimental groups consisted of a control and three nonylphenol exposures (<TEX>$1.0,\;2.5,\;and\;5.0\;{\mu}g\;NP/L$</TEX>). Mortality did not differ significantly between the control and the exposure groups. The sex ratio (F:M) was 1:1 in nature and 1:1.03 in the control group. However, it changed to 1:3.5 with <TEX>$5.0\;{\mu}g\;NP/L$</TEX> exposure. Gonad maturity in females was higher in the nonylphenol exposure groups than in the control group. By contrast, in males, it was lower in the nonylphenol exposure groups. Intersex individuals constituted 0% in nature, 3.08% in the control group, and 23.6% in the group exposed to nonylphenol, with female characteristics more prevalent than male. As the concentration of nonylphenol increased, the accumulation of lipofuscin increased in the mid-gut gland.