双齿许水蚤(Pseudodiaptomus dubia)对亚热带虾池Cu和Zn的富集

Accumulation of Copper and Zinc by a Calanoid Copepod (Pseudodiaptomus dubia) in Subtropical Shrimp Ponds

重金属污染是对虾养殖环境主要污染现象之一,查明重金属在环境中的迁移规律对养殖水质调控和对虾健康养殖具有重要意义。本文采用火焰原子吸收分光光度计测定在不同暴露时间下双齿许水蚤（Pseudodiaptomus dubia）对Cu和Zn的富集量,研究了双齿许水蚤对Cu和Zn富集动力学,并探讨了温度和盐度对其富集的影响。结果表明：双齿许水蚤对Cu和Zn的富集过程均经历了快速、慢速和平衡3个阶段,实验24 h达到富集平衡,双齿许水蚤对Cu和Zn的富集动力学参数k1（Cu）=0.077〈k1（Zn）=0.272,BCF（Cu）=0.344〈BCF（Zn）=2.252,双齿许水蚤对Zn的富集速率和富集能力均大于Cu。温度对双齿许水蚤Cu和Zn富集的影响显著（p〈0.05）,最适温度范围为15～30℃,盐度对双齿许水蚤Zn富集的影响极显著（p〈0.01）,而对Cu富集的影响不显著（p〉0.05）,对Cu和Zn适宜的富集盐度范围为10～35。这些研究结果说明,双齿许水蚤对Cu和Zn均具有较强的富集能力,在对虾养殖期间,应通过循环过滤设施去除受到重金属污染池塘中的浮游动物,减少幼虾对其摄食和虾体中重金属的积累量,从而降低食品安全隐患。

Heavy metal pollution is one of the main environment problems in the shrimp farming. The accumulation pathway of heavy metals in the farming environment is important to maintain a healthy aquaculture environment. In this study, we investigated the effects of different time and environmental conditions（temperature and salinity） on the enrichment of copper（Cu） and zinc（Zn） by Pseudodiaptomus dubia, using a flame atomic absorption spectrophotometer.Results showed that the enrichment process of Cu and Zn in P. dubia undergone three stages from fast adsorption, slow adsorption to adsorption equilibrium. The enrichment coefficient of P. dubia reached equilibrium 24 hours after experiment began. The kinetic parameters of adsorption（biological absorption rate constant, k1 and biological concentrationfactor BCF） of Cu and Znin P. dubia were k1（Cu）= 0.077 k1（Zn）= 0.272,BCF（Cu）= 0.344 BCF（Zn）= 2.252. The adsorption rate of Zn was higher than that for Cu. There was a significant effect of temperature on the enrichment of Cu and Zn（p 0.05）, with the optimal temperature ranging from 15 ℃ to 30 ℃. Salinity significantly affected Zn enrichment（p 0.01）, but did not significantly affect the Cu enrichment（p 0.05）. The favorable salinity range for Cu and Zn accumulation in P. dubia was from 10 to 35. Therefore, P. dubia had a strong ability to accumulate Cuand Zn heavy metals in subtropical shrimp farming ponds. In the stage of shrimp farming, zooplankton contaminated with heavy metals were suggested to be removed by recirculating filtration to reduce the food safety problems and maintain healthy shrimp farming.