重金属Cd与Cu在克氏原螯虾体内富集与释放规律

Biological Accumulation and Release of Cd and Cu in Procambarus clarkii

研究克氏原螯虾分别在Cd2+质量浓度为0、0.05、0.10 mg/L和Cu2+质量浓度为0、0.5、1.0 mg/L的单一水环境中暴露时,肝胰腺、鳃和肌肉对Cd和Cu的生物富集和释放特性。通过非线性拟合得到克氏原螯虾对Cd和Cu的生物富集动力学参数:富集速率常数k1、排出速率常数k2、生物富集系数(bioconcentration factors,BCF)和生物半衰期(T1/2),并得出理论富集平衡状态时生物体内Cd和Cu富集量(ρAmax)。结果表明:克氏原螯虾的肝胰腺和鳃对水体中Cd2+和Cu2+都有很强的富集特性,且富集量与富集时间、水体中Cd2+和Cu2+的质量浓度成正相关;肌肉组织中富集规律则不明显。同种重金属在不同组织中的富集量不同,即重金属富集具有组织选择性:在分别含Cd2+和Cu2+的水体中暴露实验9 d后,3种组织对Cd的富集量顺序为鳃>肝胰腺>肌肉;对Cu的富集量顺序为肝胰腺>鳃>肌肉。克氏原螯虾对Cu和Cd的富集代谢都较缓慢,暴露9 d仍未达到稳定。克氏原螯虾体内Cd和Cu的BCF范围分别约为2~207、3~226;T1/2分别约为3~29、7~36 d;在理论平衡状态下,鳃、肝胰腺和肌肉中Cu和Cd的ρAmax随着环境中Cu2+和Cd2+质量浓度的增大而增大,且呈正相关。

Biological accumulation and release of the two heavy metals Cd and Cu in gill, hepatopancreas and muscle of Procambarus clarkii were studied with initial Cd2+ concentrations of 0, 0.05 and 0.10 mg/L, and initial Cu2+ concentrations of 0, 0.5 and 1.0 mg/L, respectively. Kinetic parameters such as heavy metal uptake rate constant(k1), extraction rate constant(k2), bio-concentration factor(BCF) and biological half-life(T1/2) and equilibrium concentration(ρAmax) in vivo of the heavy metals were obtained by non-linear curve fitting. The results showed that obvious accumulation of Cd and Cu was observed in Procambarus clarkii and the concentrations of heavy metals in gill, hepatopancreas, and muscle exhibited an apparent positive correlation between accumulation time and exposure concentrations. But the concentrations of both heavy metals revealed different levels in different tissues following the decreasing order: hepatopancreas > gill > muscle for Cd, and gill > hepatopancreas > muscle for Cu. The maximal heavy metal contents(ρAmax) in gill, hepatopancreas and muscle were positively correlated to the exposure concentration. The BCF of Cd and Cu in the tissues ranged from 2 to 207 and from 3 to 226, respectively. The T1/2 of Cd and Cu in the tissues ranged from 3 to 29 d and from 7 to 36 d, respectively.