虾夷扇贝(Patinopecten yessoensis)对铅和镉的生物富集与释放规律

Study on the Accumulation and Elimination of Pb and Cd in Patinopecten yessoensis

利用双箱模型模拟了虾夷扇贝在混合暴露条件下富集、释放铅和镉的动力学特征,通过测定不同规格虾夷扇贝、不同组织富集、释放过程中铅和镉的含量并进行非线性拟合,获得不同生长阶段虾夷扇贝对铅和镉的生物富集系数BCF、吸收速率常数k1、释放速率常数k2、生物学半衰期B1/2以及不同组织中铅和镉的富集参数。结果显示,大、小两种规格虾夷扇贝对铅的BCF分别为1671、896,对镉的BCF分别为7433、1123;不同规格虾夷扇贝对铅、镉的BCF顺序为:大规格>小规格;相同规格虾夷扇贝BCF:镉>铅,表明虾夷扇贝对镉的富集能力强于铅;铅、镉的B1/2为:大规格>小规格,说明大规格的虾夷扇贝对铅、镉的代谢排出能力更强;铅在虾夷扇贝各组织中的富集顺序依次为:鳃>内脏团>闭壳肌,镉的富集顺序依次为:内脏团>鳃>闭壳肌。

The accumulation and elimination of heavy metals in shellfish are greatly affected by many factors including the type of the heavy metal, the size, tissue, and organ of the shellfish. External environmental factors are also involved such as the temperature, p H, and the concentrations of the heavy metal. Here we investigated the accumulation and elimination of two heavy metals（Pb and Cd） in Patinopecten yessoensis in a semi-static system. We measured the concentrations of Pb and Cd in different organs of P. yessoensis with different sizes. Using the two-compartment model with non-linear curve fitting, we obtained kinetic parameters such as bioconcentration factor（BCF）, uptake rate constant（k1）, elimination rate constant（k2） and biological half-life（B1/2）. P. yessoensis had high capacity of the bioaccumulation and elimination of Cd and Pb. BCF for Pb in large-size scallops and small-size scallops were 1671 and 896 respectively, and the values for Cd were 7433 and 1123 respectively. This indicated that the size of P. yessoensis had impact on the accumulation of heavy metals, and that large-size scallops had higher capacity. Given the same size, BCF for Cd was higher than Pb, which implied a preference in the bioaccumulation of Cd. The accumulation of Pb in different organs showed the order gill visceral mass adductor muscle, and the order for Cd was visceral mass gill adductor muscle. The B1/2 for both Pb and Cd was higher in large-size P. yessoensis, which suggested that large-size scallops were more capable of eliminating Pb and Cd. The elimination rate of Cd in the visceral mass was the highest among the organs, and there was no difference between the gill and the adductor muscle. Our study provided insights into the toxic effects of heavy metals in shellfish.