Department of Environmental Health Science, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Korea.
Department of Environmental Engineering, Kunsan National University, Kunsan 54150, Korea.
Environ Pollut. 2018 May;236:91-99. doi: 10.1016/j.envpol.2018.01.037.
Since the introduction of standardized nematode toxicity assays by the American Society for Testing and Materials (ASTM) and International Organization for Standardization (ISO), many studies have reported their use. Given that the currently used standardized nematode toxicity assays have certain limitations, in this study, we examined the use of a novel nematode offspring counting assay for evaluating soil ecotoxicity based on a previous soil-agar isolation method used to recover live adult nematodes. In this new assay, adult Caenorhabditis elegans were exposed to soil using a standardized toxicity assay procedure, and the resulting offspring in test soils attracted by a microbial food source in agar plates were counted. This method differs from previously used assays in terms of its endpoint, namely, the number of nematode offspring. The applicability of the bioassay was demonstrated using metal-spiked soils, which revealed metal concentration-dependent responses, and with 36 field soil samples characterized by different physicochemical properties and containing various metals. Principal component analysis revealed that texture fraction (clay, sand, and silt) and electrical conductivity values were the main factors influencing the nematode offspring counting assay, and these findings warrant further investigation. The nematode offspring counting assay is a rapid and simple process that can provide multi-directional toxicity assessment when used in conjunction with other standard methods.
自美国测试材料学会（ASTM）和国际标准化组织（ISO）引入标准化线虫毒性测定法以来，已有许多研究报告了其使用情况。鉴于目前使用的标准化线虫毒性测定法存在一定的局限性，在本研究中，我们基于先前用于回收活体成年线虫的土壤-琼脂分离方法，检查了使用新型线虫后代计数测定法来评估土壤生态毒性的情况。在这个新的测定法中，使用标准化毒性测定法程序将成年秀丽隐杆线虫暴露于土壤中，然后在琼脂平板上通过微生物食物源吸引测试土壤中的线虫后代，并对其进行计数。与先前使用的测定法相比，该方法在终点上有所不同，即线虫后代的数量。使用金属污染土壤证明了生物测定法的适用性，结果显示出金属浓度依赖性的响应，并且还使用了 36 个具有不同物理化学性质且含有各种金属的田间土壤样本。主成分分析表明，质地分数（粘土、沙子和粉土）和电导率值是影响线虫后代计数测定法的主要因素，需要进一步研究。线虫后代计数测定法是一种快速而简单的过程，与其他标准方法结合使用时，可以提供多方向的毒性评估。
