Division of Biological Sciences, University of Missouri, 212 Tucker Hall, Columbia, MO 65211, USA.
Arch Environ Contam Toxicol. 2010 Apr;58(3):819-27. doi: 10.1007/s00244-009-9390-z. Epub 2009 Sep 19.
Low levels of agricultural herbicides often contaminate surface water and might persist throughout the growing season, potentially acting as stressors on aquatic organisms. Although low-dose, chronic exposures to agrochemicals are likely common for many nontarget organisms, studies addressing these effects using end-use herbicide formulations are rare. We exposed three common species of tadpoles to conservative levels of atrazine, S-metolachlor, and glyphosate end-use herbicide formulations throughout the larval period to test for survival differences or life-history trait alterations. Exposure to the glyphosate product Roundup WeatherMax at 572 ppb glyphosate acid equivalents (a.e.) resulted in 80% mortality of western chorus frog tadpoles, likely as a result of a unique surfactant formulation. Exposure to WeatherMax or Roundup Original Max at 572 ppb a.e. also lengthened the larval period for American toads. Chronic atrazine and S-metolachlor exposures induced no significant negative effects on survival, mass at metamorphosis, or larval period length at the levels tested. These results highlight the importance of explicitly tying chronic tests to the natural environment and considering contributions of surfactant/adjuvant components to end-use formulation toxicities, even between very similar products.
低水平的农业除草剂经常污染地表水，并可能在整个生长季节持续存在，对水生生物构成潜在的胁迫。尽管许多非目标生物可能经常受到低剂量、慢性的农用化学品暴露，但使用终端用途除草剂配方来研究这些影响的研究很少。我们让三种常见的蝌蚪在整个幼虫期接触保守剂量的莠去津、S-甲草氯和草甘膦终端用途除草剂配方，以测试生存差异或生活史特征改变。暴露在 572 ppb 草甘膦酸当量（a.e.）的草甘膦产品 Roundup WeatherMax 下，西部合唱蛙蝌蚪的死亡率达到 80%，可能是由于独特的表面活性剂配方。暴露在 WeatherMax 或 Roundup Original Max 下 572 ppb a.e. 也会延长美洲蟾蜍的幼虫期。在测试的浓度下，慢性莠去津和 S-甲草氯暴露对生存、变态时的体重或幼虫期长度没有显著的负面影响。这些结果强调了将慢性测试与自然环境明确联系起来的重要性，并考虑到表面活性剂/助剂成分对终端用途配方毒性的贡献，即使是在非常相似的产品之间也是如此。
