Surface water mineralization of isopyrazam according to OECD 309: Observations on implementation of the new data requirement within agrochemical regulation
Surface water mineralization of isopyrazam according to OECD 309: Observations on implementation of the new data requirement within agrochemical regulation
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DOI：
10.1002/etc.2490
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发表时间：
2014-03
影响因子：
4.1
通讯作者：
Laurence H. Hand;Harriet J. Moreland
中科院分区：
文献类型：
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作者：
Laurence H. Hand;Harriet J. Moreland
地表水矿化研究（根据经济合作与发展组织[OECD]指南OECD 309）是欧盟农用化学品法规中的一项新要求;因此，行业对该试验几乎没有经验。该指南允许在试验设计中有许多选择，特别是在漫射光下进行研究和包括悬浮沉积物接种物的选择。本研究旨在研究这些选项对代表性化合物降解速率的潜在影响。选择杀真菌剂吡唑萘菌胺是因为先前已证明其在荧光光暗循环下易受光养生物代谢的影响。在代表大型开放水体深度的光强度（<入射强度的7%）下研究了漫射光的影响，结果表明，光养微生物对吡唑萘菌胺的代谢很快（50%供试化合物的中位降解时间[DT 50] < 50天），而在连续黑暗中的降解可忽略不计。此外，在2个不同的光强度的调查导致类似的降解率，这表明这种转化机制是不成比例的光强度，提供有足够的光进行光合作用。除了在沉积物浓度极高的情况下，悬浮沉积物的加入对吡唑萘草胺的降解率没有显著影响，但认为这并不能代表大型开放水体的条件。环境毒理化学2014;33：516-524。© 2013 SETAC
A surface water mineralization study (according to the Organisation for Economic Co‐operation and Development [OECD] guideline OECD 309) is a new requirement in European Union agrochemical regulations; therefore, industry has little experience with this test. The guideline allows for a number of options within the test design, notably the options to conduct the study under diffuse light and to include an inoculum of suspended sediment. The present study was designed to investigate the potential impact of these options on the degradation rate of a representative compound. The fungicide, isopyrazam, was chosen as it was previously shown to be susceptible to metabolism by phototrophic organisms under a fluorescent light–dark cycle. The impact of diffuse light was investigated at light intensities representative of those at depth in large, open water bodies (<7% of the incident intensity), and it was demonstrated that metabolism of isopyrazam by phototrophic microorganisms was rapid (median degradation time for 50% of the test compound [DT50] < 50 d), whereas degradation in continuous darkness was negligible. Furthermore, investigation at 2 different light intensities resulted in similar degradation rates, indicating that this transformation mechanism was not proportional to light intensity, provided that there was sufficient light for photosynthesis to occur. Inclusion of suspended sediment did not have a significant impact on the degradation rate of isopyrazam, except at extremely high sediment concentrations, which were not considered representative of conditions in large, open water bodies. Environ Toxicol Chem 2014;33:516–524. © 2013 SETAC