Spurgeon D J, Svendsen C, Kille P, Morgan A J, Weeks J M
Centre for Ecology and Hydrology, Monks Wood, Abbotts Ripton, Huntingdon, Cambridgeshire PE28 2LS, UK.
Ecotoxicol Environ Saf. 2004 Jan;57(1):54-64. doi: 10.1016/j.ecoenv.2003.08.003.
In this study, the effects of two metals, copper and cadmium, on the growth and development of juvenile Lumbricus rubellus were measured in a toxicity test in which individuals were grown in isolation. This design had a number of advantages over traditional test systems for earthworms. Importantly, the test is specifically designed to measure two juvenile traits (survival over and length of the juvenile period) that have been shown to have a high sensitivity for determining population growth rate. The test system also maximizes replication, while allowing time-series-based monitoring of individual growth. For both metals, significant exposure-dependent effects on survival, growth, development time, and (less certainly) maturation weight were observed. Comparisons of the relative toxicity of the two metals indicated different concentration-response relationships. For copper, hormesis was found at low levels, while only at the highest soil concentration tested (10.07 micromol g(-1)) were (severe) toxic effects present. For cadmium, hormesis was also evident at the lowest concentration tested; however, at soil levels above this, a graded concentration-dependent toxic effect was apparent. These differences in the exposure response patterns can be (tentatively) explained in terms of the mechanisms for handling copper (an essential metal for earthworms) and cadmium (a putative nonessential element). The applicability of the test for routine measurement of chemical effects on ecologically relevant juvenile traits is also outlined and future developments are discussed.
在本研究中，通过一项毒性试验测定了铜和镉这两种金属对赤子爱胜蚓幼体生长发育的影响，试验中个体单独饲养。与传统的蚯蚓测试系统相比，这种设计有许多优点。重要的是，该试验专门设计用于测量两个幼体特征（幼体期的存活率和时长），这些特征已被证明对确定种群增长率具有高度敏感性。该测试系统还最大限度地增加了重复次数，同时允许对个体生长进行基于时间序列的监测。对于两种金属，均观察到了对存活、生长、发育时间以及（不太确定的）成熟体重的显著暴露依赖性影响。两种金属相对毒性的比较表明了不同的浓度 - 反应关系。对于铜，在低水平时发现了 hormesis 现象，而仅在测试的最高土壤浓度（10.07 μmol g⁻¹）下才出现（严重）毒性作用。对于镉，在测试的最低浓度下也明显存在 hormesis 现象；然而，在此浓度以上的土壤水平时，明显出现了分级的浓度依赖性毒性作用。这些暴露反应模式的差异可以（初步）根据蚯蚓处理铜（一种对蚯蚓必需的金属）和镉（一种假定的非必需元素）的机制来解释。还概述了该试验在常规测量化学物质对生态相关幼体特征影响方面的适用性，并讨论了未来的发展。
