Biodegradation tests are essential for characterizing the behavior of organic micropollutants in the environment, but they are carried out almost exclusively in the laboratory. Test parameters such as temperature and test chemical concentration are often applied in ways that affect observed biodegradation, and laboratory testing requires sophisticated temperature-controlled facilities. We developed a field-based test based on OECD 309 which minimizes the need for laboratory resources such as temperature-controlled facilities by using bottles incubated in the natural water body. The test also utilized contaminant residues present in unspiked natural water to increase the relevance of the results to the local system. A test in a local river and a matching lab-based test were conducted in parallel. We quantified 26 of 40 targeted micropollutants and observed dissipation for 13. Significant differences in half-life (up to a factor of 3.5) between lab and field bottles were observed for 7 compounds, with 6 of 7 degrading more slowly in field bottles. For 4 of these, dissipation was positively correlated to the neutral fraction of the chemical. Differences in the neutral fraction arose due to a higher pH in the lab bottles induced by outgassing of CO2 from the oversaturated river water. We conclude that pH is an important parameter to control in biodegradation testing and that field-based tests may be more environmentally relevant.

中文翻译：

---

一个简单的基于现场的生物降解测试表明，pH在实验室生物降解测试中的控制参数不足。

生物降解测试对于表征有机微污染物在环境中的行为至关重要，但是它们几乎只能在实验室中进行。通常以影响观察到的生物降解的方式应用温度和化学浓度等测试参数，而实验室测试则需要复杂的温度控制设备。我们基于OECD 309开发了基于现场的测试，该测试通过使用在天然水体中孵育的瓶子来最大限度地减少对实验室资源（如温度控制设施）的需求。该测试还利用了未加标天然水中存在的污染物残留，以提高结果与当地系统的相关性。并行进行了当地河流的测试和基于实验室的匹配测试。我们对40种目标微污染物中的26种进行了定量，并观察了13种消散。观察到7种化合物在实验室瓶和田间瓶之间的半衰期存在显着差异（最高3.5倍），其中7种化合物中有6种在田间瓶中的降解速度较慢。对于其中的4种，耗散与化学物质的中性分数呈正相关。中性分数的差异是由于过饱和河水中的CO2脱气而导致实验室瓶中的pH值较高所致。我们得出结论，pH是控制生物降解测试的重要参数，基于现场的测试可能与环境更加相关。耗散与化学品的中性分数呈正相关。中性分数的差异是由于过饱和河水中的CO2脱气而导致实验室瓶中的pH值较高。我们得出结论，pH是控制生物降解测试的重要参数，基于现场的测试可能与环境更加相关。耗散与化学品的中性分数呈正相关。中性分数的差异是由于过饱和河水中的CO2脱气而导致实验室瓶中的pH值较高所致。我们得出结论，pH是控制生物降解测试的重要参数，基于现场的测试可能与环境更加相关。