Department of Zoology and Animal Cellular Biology, University of the Basque Country, Box 644, 48080, Bilbao, Spain,
Ecotoxicology. 2013 Dec;22(10):1445-60. doi: 10.1007/s10646-013-1131-4. Epub 2013 Oct 2.
The aim of the present study was to estimate critical body residues (CBRs) of three metals [cadmium (Cd), copper (Cu), chromium (Cr)] in the aquatic oligochaete Tubifex tubifex based on lethal (LBR) and sublethal effects (CBR), and to discuss the relevance of the exposure to sediment for deriving CBR. Toxicity parameters (LC50, EC50, LBR50 and CBR50) were estimated for each metal by means of data on survival and on several sublethal variables measured in short-term (4 days), water-only exposures and in long-term, chronic (14 and 28 days) exposures using metal-spiked sediment. Sublethal endpoints included autotomy in short-term exposure, as well as reproduction and growth in chronic bioassays. LBR50 and CBR50 were 3-6 times higher in sediment than in water-only exposure to Cd and about 2-11 times higher for Cu, depending on the measured endpoint; however, for Cr these parameters varied only by a factor of 1.2. Cu and Cr LBR50 and CBR50 values in 96 h water-only exposure were very similar (survival 2.39 μmol Cu g(-1) dw, 2.73 μmol Cr g(-1) dw; autotomy 0.53 μmol Cu g(-1) dw, 0.78 μmol Cr g(-1) dw). However, in metal-spiked sediments, 28 d CBR50 values for autotomy, reproduction and growth ranged 6.76-29.54 μmol g(-1) dw for Cd, 3.88-6.23 μmol g(-1) dw for Cu, 0.65 μmol g(-1) dw for Cr (calculated only on total number of young). Exposure conditions (time and presence/absence of sediment) seem to be influential in deriving metal CBR values of Cd and Cu, while appear to be irrelevant for Cr. Thus, CBR approach for metals is complex and tissue residue-toxicity relationship is not directly applicable so far.
本研究旨在基于致死（LBR）和亚致死效应（CBR）估算三种金属[镉（Cd）、铜（Cu）、铬（Cr）]在水生寡毛纲环节动物水丝蚓（Tubifex tubifex）体内的关键残留量（CBR），并讨论暴露于沉积物中推导 CBR 的相关性。通过在短期（4 天）水相暴露和长期（14 和 28 天）慢性暴露中测量的生存和几种亚致死变量的数据，用金属加标沉积物估算了每种金属的毒性参数（LC50、EC50、LBR50 和 CBR50）。亚致死终点包括短期暴露中的自切，以及慢性生物测定中的繁殖和生长。与水相暴露相比，Cd 在沉积物中的 LBR50 和 CBR50 分别高出 3-6 倍，而 Cu 则高出 2-11 倍，具体取决于测量的终点；然而，对于 Cr，这些参数的变化仅为 1.2 倍。96 小时水相暴露中 Cu 和 Cr 的 LBR50 和 CBR50 值非常相似（生存 2.39 μmol Cu g(-1) dw，2.73 μmol Cr g(-1) dw；自切 0.53 μmol Cu g(-1) dw，0.78 μmol Cr g(-1) dw）。然而，在加金属的沉积物中，28 天的自切、繁殖和生长的 CBR50 值范围为 Cd 的 6.76-29.54 μmol g(-1) dw、Cu 的 3.88-6.23 μmol g(-1) dw、Cr 的 0.65 μmol g(-1) dw（仅基于幼体总数计算）。暴露条件（时间和有无沉积物）似乎对推导 Cd 和 Cu 的金属 CBR 值有影响，而对 Cr 似乎没有影响。因此，目前金属的 CBR 方法比较复杂，组织残留与毒性的关系还不能直接应用。
