摘要
应用半静态双箱模型室内模拟了牡蛎对四种重金属 (As、Hg、Cd、Pb)的生物富集实验 ,通过非线性拟合得到了牡蛎富集重金属的吸收速率常数 k1 、排出速率常数 k2 、生物富集因子 BCF、生物学半衰期 B1 /2 等动力学参数。结果表明 :吸收速率常数 k1及生物富集因子 BCF均随着外部水体浓度的增大而减小而平衡状态下生物体内金属含量 CAmax随着外部水体浓度的增大而增大 ,且成显著正相关 ,这说明牡蛎比较理想的重金属 Hg、Cd、Pb污染的指示生物。
Heavy metal pollution in benthic filter-feeding bivalves has been received more and more attention. With regard to the studies in this field, the double-boxes kinetic model is a new developed mathematic model. In the present study, accumulation and elimination of four heavy metals (As, Hg, Cd and Pb) in O.gigas thunberg were investigated by using the double-boxes kinetic model. A semi-static system was maintained throughout a 30-day exposure period in different concentrations of heavy metals at 12.34±2.28℃. During the uptake phase, water was changed on alternate days, sufficient to maintain relatively constant concentrations of heavy metals, and the test organism was fed with Chlorella twice each day. Three animals were sampled periodically and frozen immediately for late analysis. Then, remaining O.gigas thunberg were transferred to clean seawater for the elimination phase of 35 days, during which the flow-through method was adopted and the natural seawater temperature changed to 6.63±3.12℃. Also, three animals were sampled and subjected to the same procedures described above. According to the double-boxes kinetic model, the following two equations could be used for the accumulation and elimination phase,respectively: C_A=C_0+C_Wk_1k_2(1-e^(-k_2t)), C_A=C_Wk_1k_2(e^(-k_2(t-t^*))-e^(-k_2t)) Based on the above equations and by non-linear fitting, some kinetic parameters were obtained, including uptake rate constant (k_1), extracting rate constant (k_2), bioconcentration factor (BCF), and biological half-life (B_(1/2)). The results indicated that that: (1) the uptake rate constant (k_1) all decreased with the increase of heavy metal concentration in ambient seawater; (2) BCF decreased generally with the increase of heavy metal concentrations in ambient seawater; (3) the bioconcentration factors (BCF) of the four heavy metals in O.gigas Thunberg were in the sequences of HgCd>PbAs; (4) the maximal metal contents in test organism (C_(Amax)) at steady-state increased with the increase of heavy metal concentrations in ambient seawater, presenting significantly positive correlation; O.gigas Thunberg proved to be a useful indicator organism in the assessment of heavy metal ( Hg, Pb, Cd) contamination. (5) the biological half-life of Cd in O.gigas Thunberg was longer than those of Hg, Pb, As.
出处
《生态学报》
CAS
CSCD
北大核心
2004年第5期1086-1090,共5页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目 ( 3 0 2 70 2 1)
农业科技跨越计划专项基金资助项目 ( 2 0 0 1-2 0 )~~
关键词
生物富集
重金属
海洋经济贝类
bioconcentration
heavy metals
marine commercial molluscs
