Nandini S, Chaparro-Herrera Diego De Jesús, Cárdenas-Arriola Sara Leticia, Sarma S S S
UIICSE, Division of Research and Postgraduate Studies, National Autonomous University of Mexico, Campus Iztacala, Los Reyes, Tlalnepantla, State of Mexico, Mexico.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2007 Aug;42(10):1467-72. doi: 10.1080/10934520701480896.
In the present work, we quantified the harmful effects of Cd(+ 2) to Brachionus macracanthus using both acute (median lethal) and chronic (population growth) toxicity tests. Chronic toxicity tests were conducted under 4 different concentrations (0.000625-0.005 mg L(- 1)) of cadmium chloride at 23 degrees C under 3 food (Chlorella vulgaris) levels (0.5 x 10(6), 1.0 x 10(6) and 2.0 x 10(6) cells mL(- 1)) using static renewal system for three weeks. The median lethal concentration bioassayed at 24 h (LC(50)) for B. macracanthus was 0.19 mg L(- 1) of CdCl(2). Cadmium adversely affected the population growth of B. macracanthus at all tested concentrations. Increase in algal food had a positive effect on the rotifer growth in controls; with increase in Cd levels, the population growth of B. macracanthus decreased even under the highest food level tested. The peak population abundance of B. macracanthus in controls at the highest food level of 2.0 x 10(6) cells mL(- 1) was 40 ind. mL(- 1). Depending on the heavy metal concentration and the algal level, the population growth rate (r) of B. macracanthus varied from 0.02 to 0.28 day(- 1). The relatively higher sensitivity of B. macracanthus to cadmium toxicity is discussed in relation to other species of the same genus.
在本研究中，我们通过急性（半数致死）和慢性（种群增长）毒性试验，对镉离子（Cd(+2)）对大型棘尾轮虫（Brachionus macracanthus）的有害影响进行了量化。慢性毒性试验是在23摄氏度下，使用静态更新系统，在3种食物（普通小球藻（Chlorella vulgaris））水平（0.5×10(6)、1.0×10(6)和2.0×10(6)个细胞 mL(-1)）下，对4种不同浓度（0.000625 - 0.005 mg L(-1)）的氯化镉进行为期三周的试验。大型棘尾轮虫在24小时的半数致死浓度（LC(50)）生物测定值为0.19 mg L(-1)的CdCl(2)。在所有测试浓度下，镉对大型棘尾轮虫的种群增长均产生了不利影响。在对照组中藻类食物的增加对轮虫生长有积极作用；随着镉水平的增加，即使在测试的最高食物水平下，大型棘尾轮虫的种群增长也会下降。在最高食物水平2.0×10(6)个细胞 mL(-1)的对照组中，大型棘尾轮虫的种群丰度峰值为40个个体 mL(-1)。根据重金属浓度和藻类水平，大型棘尾轮虫的种群增长率（r）在0.02至0.28天(-1)之间变化。文中还讨论了大型棘尾轮虫相对于同一属其他物种对镉毒性的相对较高敏感性。
