Department of Pure and Applied Zoology, University of Reading, PO Box 228, RG6 2AJ, Reading, UK.
Ecotoxicology. 1994 Mar;3(1):68-78. doi: 10.1007/BF00121389.
: Porcellio scaber Latreille (Crustacea: Isopoda) of one month in age were reared for a year on leaf litter of field maple (Acer campestre) contaminated in the laboratory with a range of concentrations of cadmium, copper, lead or zinc. The metals were applied topically to the leaves as nitrates. Growth and survival, numbers of live offspring produced by females that matured, and concentrations of metals in adult isopods at the end of the experiment were measured.'Critical concentrations' of metals in food at which all the isopods died before producing offspring were 100 μg Cd g(-1), 100 μg Cu g(-1), 2000 μg Pb g(-1) and 1000 μg Zn g(-1) (on a dry weight basis). The relative toxicities of the four metals in the laboratory were compared with concentrations of cadmium, copper, lead and zinc in surface leaf litter in the vicinity of a primary smelting works at Avonmouth, South West England. The results support the hypothesis that the absence of Porcellio scaber from sites in the immediate vicinity of the factory is due to zinc poisoning. Although cadmium is approximately ten times more toxic to isopods than zinc in the laboratory, zinc is most likely to be killing isopods in the field because its concentration is always at least 30 times higher than cadmium in Avonmouth leaf litter, and more than 100 times higher at most sites.Populations of Porcellio scaber survive in field sites where surface leaf litter contains up to 5000 μg Zn g(-1). This is at least five times higher than the 'critical concentration' in laboratory experiments. Thus, the methodology for assessing metal toxicity described in this paper, exaggerates the potential effects of metals to isopods in the field. Such differences between laboratory and field toxicities of metals should be taken into account when environmental protection levels for metals are being proposed for soil invertebrates based on ecotoxicological tests conducted in the laboratory.
一个月大的扁形卷甲虫（甲壳纲：等足目）在经过一年的田间枫木叶（Acer campestre）饲养后，其叶片受到一系列浓度的镉、铜、铅或锌的污染。这些金属以硝酸盐的形式被施加到叶片上。实验结束时，测量了生长和存活情况、成熟雌虫所产活后代的数量以及成虫体内金属的浓度。所有等足目动物在产生后代之前死亡的食物中金属的“临界浓度”分别为 100μgCdg(-1)、100μgCug(-1)、2000μgPbg(-1)和 1000μgZng(-1)（干重基础）。四种金属在实验室中的相对毒性与英格兰西南部阿冯茅斯（Avonmouth）主要冶炼厂附近地表落叶层中镉、铜、铅和锌的浓度进行了比较。结果支持了这样一种假设，即在工厂附近的地点没有扁形卷甲虫，是由于锌中毒所致。尽管在实验室中，镉对等足目动物的毒性比锌大约高十倍，但锌很可能是在田间杀死等足目动物的原因，因为在阿冯茅斯落叶层中，锌的浓度总是至少比镉高 30 倍，而在大多数地点，锌的浓度比镉高 100 倍以上。在地表落叶层中锌含量高达 5000μg g(-1)的野外地点，扁形卷甲虫种群得以存活。这至少比实验室实验中的“临界浓度”高五倍。因此，在根据实验室进行的生态毒理学测试为土壤无脊椎动物提出金属保护水平时，应该考虑到本文所述评估金属毒性的方法对野外等足目动物的潜在影响。在实验室和野外金属毒性之间存在这种差异时，应该考虑到这一点。
