泥蚶不同组织器官对重金属(Cu、Pb、Cd)的富集规律

通过室内半静态暴毒试验,研究三种重金属(Cu、Pb、Cd)的单一与联合胁迫作用下,泥蚶(Tegillarca granosa)不同组织器官对重金属的富集能力、富集途径,以及两两重金属之间的交互作用。结果发现:单一胁迫条件下,泥蚶各组织器官对Cu的富集能力是鳃>内脏团>肌肉,对Pb和Cd的富集能力是鳃>肌肉>内脏团;肌肉和鳃对Pb的富集速率显著(P<0.05)高于内脏团,即泥蚶对Pb的富集可以通过鳃的呼吸作用和体表的渗透作用两条途径实现。联合胁迫条件下,Cd能够拮抗Cu的富集;一定量的Cu也能够在内脏团中发挥作用,拮抗Pb和Cd的累积;在其他各组织中累积的Cu和Cd则不影响Pb的累积,说明Cd和Cu在泥蚶体内以可溶形式存在,而Pb以不溶形式存在。重金属的富集与金属种类、金属浓度、累积途径、生物体的解毒机制等等多种因素有关。

Accumulation mechanism of heavy metals (Cu, Pb, Cd) in different tissues of Tegillarca granosa

The semi-static exposure toxicity test were conducted in laboratory to study the accumulation of heavy metal(Cu,Pb,Cd) and bio-concentrated pathway in different tissues of Tegillarca granosa under single and combined heavy metal exposure.The results showed that under the single heavy metal exposure,the metal contents of Cu in different tissues were with the sequences of gills>viscera>muscle,and metal contents of Pb and Cd were gills>muscle >viscera.The accumulation of Pb in muscle and gill were significantly higher than in viscera(P<0.05),which might be caused by respiration of gill and osmotic absorption of body surface.Under the combined heavy metal exposure,there was a competitive adsorption relationship between Cu and Cd.A certain amount of Cu could activate a variety of enzymes in the visceral mass,and those enzymes could clear Pb and Cd.In other tissues,Cu and Cd have not influenced to the accumulation of Pb.The results showed that the localization of Cu and Cd were in soluble fraction mainly,whereas Pb was located in insoluble fraction.The accumulation of heavy metals was closely bonded to the metal type,concentration of metal,metal bio-concentration pathway,detoxification mechanism of organism and so on.