菲律宾蛤仔对6种重金属的生物富集动力学

Kinetic study on the bioconcentration of six heavy metals in Ruditapes philippinarum

中文关键词: 菲律宾蛤仔  重金属  生物富集  双箱动力学模型

英文关键词: Ruditapes philippinarum  Heavy metal  Bioconcentration  Two-compartment kinetic model

中文摘要:

      以菲律宾蛤仔为实验生物，应用半静态双箱模型室内模拟了菲律宾蛤仔对混合暴露条件下6种重金属Cu、Zn、Pb、Cd、Hg、As的生物富集实验，通过对菲律宾蛤仔体内重金属含量变化进行非线性拟合，得到其对重金属的生物富集系数、生物富集动力学参数。结果表明，到富集实验结束时菲律宾蛤仔对高、中浓度组中Cu、Zn、Pb和Cd的生物富集系数分别是66.99、18.49、57.11、25.81和72.46、35.72、117.91、41.83，对其低浓度组中Hg和As的富集规律不明显；吸收速率常数k1及生物富集系数均随外部水体金属浓度的增加而减少；通过生物富集系数发现，菲律宾蛤仔对4种重金属的富集能力由大到小为Pb>Cu>Cd>Zn；通过χ2及F检验发现，生物双箱动力学模型可较好反映混合暴露条件下菲律宾蛤仔对重金属的富集特征。

英文摘要:

      Heavy metal pollution in filter-feeding bivalves has received more and more attentions. With regard to the studies in this field, the two-compartment kinetic model is a new mode for rapid determination of bioconcentration factor（BCF）. With a mixed solution of six heavy metals(Cu, Zn, Pb, Cd, Hg,and As), kinetic parameters of bioconcentertion in Ruditapes philippinarum were measured using a two compartment kinetic model. A semi static system was maintained throughout a 15 day exposure period in different concentrations of heavy metals at 15-5±2℃. During the uptake phase, water was changed every day, sufficient to maintain relatively constant concentrations of heavy metals. At 0d, 2d, 5d, 8d, 11d and 15d, R. philippinarum was sampled, and the samples were frozen immediately for the following analysis. Kinetic parameters of bioconcentration were obtained from the two-compartment model by nonlinear curve fitting, including uptake rate constant (k1), elimination rate constant (k2) and bioconcentration factor. The results showed that in the high and medium concentration group the BCF of Cu, Zn, Pb, and Cd in R. philippinarum were 66.99, 18.49, 57.11, 25.81 and 72.46, 35.72, 117.91, 41.83, respectively. Hg, As, and the low concentration group of Cu, Zn, Pb, Cd enrichment regularity was not obvious. The uptake rate constant and bioconcentration factor decreased with the increase of heavy metal exposure concentration in ambient seawater. The ability of accummlation of Cu, Zn, Pb, Cd, Hg, and As in R. philippinarum were Pb>Cu>Cd>Zn. χ2 and F tests for goodness of fit test showed that the fitting data of χ2 value were less than 0.71(critical value), which suggests that the fitting goodness was acceptable. Two-compartment kinetic model could fit well the accumulation of heavy metals in R. philippinarum.