摘要
以文蛤(Meretrixmeretrix)、太平洋牡蛎(Crassostrea gigas)、栉孔扇贝(Chlamys farreri)3种经济贝类为试验生物,应用生物富集双箱动力学模型,研究了暴露在不同浓度的As3+溶液中3种贝类对无机砷的耐受性。通过对富集与代谢过程中贝类体内无机砷含量的监测及对结果的非线性拟合,得出3种贝类富集无机砷的吸收速率常数(k1)、排出速率常数(k2)、生物富集系数(BCF)、生物半衰期(B1/2)等动力学常数。试验结果显示,双箱动力学模型能较好地描述3种经济贝类对无机砷的富集与代谢情况。3种贝类对无机砷的吸收速率常数(k1)随着外部水体中As3+浓度的增大基本上呈减小趋势,而排出速率常数(k2)与水体中As3+浓度无明显相关性;BCF大体随着外部水体As3+浓度的增大而减少,对无机砷的富集能力依次为文蛤>太平洋牡蛎>>栉孔扇贝;平衡状态下3种贝类体内无机砷含量(CAmax)与暴露水体中的As3+浓度之间呈正相关性,均为无机砷的净积累者;无机砷在3种贝类体内的半衰期B1/2随着As3+浓度的增大基本上减小,依次为太平洋牡蛎>栉孔扇贝≥文蛤。
Arsenic is a poisonous and harmful element.In natural state,arsenic compounds exist in various forms.The toxicity of inorganic arsenic is the strongest.The current research focus on the existing forms of arsenic compounds in seafood and its toxicity.Bivalves become the main research object because of its strong ability in biological enrichment.The bio-concentration and elimination of inorganic arsenic in three kinds of economical shellfish（Meretrix meretrix,Crassostrea gigas,Chlamys farreri） were investigated in double-boxes kinetic model.A semi-static system was maintained throughout a 35-day exposure period in different concentrations of As3＋.Then,the test organism was transferred to clean seawater for an elimination period of 30 days.During the entire test,experimental seawater and clean seawater was changed every 24 hours.The test organism was fed twice each day.Samples were taken every 5 days.Taking different water environment into account,the accumulation period and the elimination period were analyzed separately.Acording to the double-boxes kinetic model,the following two equations could be used for the accumulation and elimination phase： CA=C0＋CWk1k2（1-e-k2t）,CA=CWk1k2（e-k2（t-t＊）-e-k2t）.In addition,three other equations（BCF=k1/k2,B1/2=ln2k2,CAmax=BCF×CW） were used.Kinetic parameters of bio-concentration were obtained from the double-boxes kinetic model by nonlinear cure fitting,including uptake rate constant（k1）,elimination rate constant（k2）,bio-concentration factor（BCF） and biological half-life（B1/2）.Results showed：（1） there was no abnormal mortality during the experiment,which showed that the three kinds of shellfish could tolerate a certain concentration of As3＋.The concentration of inorganic arsenic in the tissue of the test organism always reached the maximum before the thirty-fifth day.This phenomenon also occurred in other researches.The author supposed that there was a equilibrium concentration which had close relationship with Metallothinein（MT）;（2） the bio-concentration and elimination of these three kinds of economical shellfish to inorganic arseni could be well described by the double-boxes kinetic model,although there were many biotic factors and non-biotic factors;（3） under experimental conditions,the uptake rate constant（k1 or k1） basically decreased with the increasing concentration of As3＋ in water,while the elimination rate constant（k2 or k2） was not distinctly related;（4） the bio-concentration factor（BCF） used to describe the accumulation ability basically decreased with the increasing concentration of As3＋ in water,and the accumulation order was Meretrix meretrixsCrassostrea gigaChlamys farreri;（5） the maximal metal content in test organism（CAmax） at steady-state was in the linear proportion with As3＋ concentrations through short exposure.The accumulation ability of inorganic arsenic in these three kinds of economical shellfish was net;（6） the biological half-life（B1/2） decreased while the concentration of As3＋ increased,and the order of biological half-life（B1/2） was Crassostrea gigaChlamys farreri≥Meretrix meretrixs.
出处
《海洋渔业》
CSCD
北大核心
2011年第3期325-334,共10页
Marine Fisheries
基金
国家海洋局海洋公益性行业科研专项经费项目(200805031):黄渤海重点海域贝类养殖环境安全评价及其监控体系技术研究
关键词
经济贝类
无机砷
生物富集
代谢
Economical shellfish
Inorganic arsenic
Bio-concentration
Elimination
