摘要:
采用半静水式毒性试验,研究了6种苯系物(苯、甲苯、乙基苯、邻-二甲苯、间-二甲苯、对-二甲苯)对虾夷扇贝的生殖毒性作用。在水温(16 ±0.5)℃、盐度30.0、pH 8.0条件下,用0.5、2.5、12.5 mg·L-1的苯、甲苯、乙基苯、邻-二甲苯、间-二甲苯、对-二甲苯处理虾夷扇贝的精子、胚胎和幼体,观察6种苯系物对虾夷扇贝的精子活力、卵子受精率、胚胎延滞率、胚胎畸形率、孵化率、幼体畸形率的影响。同时通过透射电镜观察6种苯系物(2.5 mg·L-1)对虾夷扇贝精子超微结构的损伤作用。结果发现:不同浓度苯系物处理组与对照组(0.0 mg·L-1)相比,虾夷扇贝精子的运动时间、卵子受精率及胚胎孵化率显著降低;胚胎发育延滞率、胚胎畸形率和幼体畸形率显著增加为并与处理浓度之间存在显著的剂量-效应关系。以上结果表明实验浓度下,6种苯系物对虾夷扇贝具有较强的胚胎毒性和生殖毒性作用。通过电镜切片发现,2.5 mg·L-1的苯、甲苯、乙基苯、邻-二甲苯、间-二甲苯、对-二甲苯导致虾夷扇贝精子超微结构损伤,表现为:精子质膜断裂、部分溶解,线粒体质膜和内嵴断裂、部分溶解。苯系物对虾夷扇贝精子超微结构的损伤可能是影响其精子活力和降低卵子受精率的主要原因之一。上述结果为苯系物对海洋贝类的生殖毒性评价提供基础数据。
Abstract:
The reproductive toxic effects of six kinds of benzene series compounds, benzene, toluene, ethyl benzene, o xylene, m xylene, p xylene (BTEXs) on the Japanese scallop (Mizuhopecten yessoensis) were conducted. The spermatozoa, embryos and early larvae were treated with BTEXs of three different concentrations (0.5, 2.5, 12.5 mg·L-1) at the condition of water temperature (16 ±0.5)℃, salinity of 30.0 and pH 8.0. The reproductive toxicities of these tested chemicals were evaluated using the sperm motility (SM), fertilization rate (FR), arresting and delaying embryos rate (ADER), malformed embryos rate (MER), hatching rate (HR) and malformed larvae rate (MLR). In the meantime, the ultrastructure damage of sperms treated with 2.5 mg·L-1 BTEXs were observed using transmission electron microscopy. The results showed that the SM, FR, HR in different concentrations of these treated groups were significantly decreased compared with the control (0.0 mg·L-1) group, and the ADER, MER, MLR increased significantly along with the increase of BTEXs concentrations. The toxic effects and the concentrations of BTEXs showing obvious dose response relation suggested that the BTEXs had embryonic and reproductive toxicities. The ultrastructure damage of sperm included the cytoplasmic membrane, mitochondrial membrane and cristae broken, partially dissolved after exposed to 2.5 mg·L-1 BTEXs. The reduction of FR and SM might be related to the ultrastructure damage of spermatozoa could result from BTEXs. The results presented in this study will provide basic data for assessing the reproductive toxic effects of BTEXs on the marine scallop.
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