Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Kamenice 753/5, Brno, CZ-62500, Czech Republic.
Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Kamenice 753/5, Brno, CZ-62500, Czech Republic.
Environ Pollut. 2018 May;236:257-264. doi: 10.1016/j.envpol.2018.01.082. Epub 2018 Feb 2.
Agriculture is today indispensably connected with enormous use of pesticides. Despite tough regulation, their entrance into soil cannot be excluded and they might enter soil organisms and plants and continue further to terrestrial food chains. This study was conducted to investigate the bioaccumulation of two pesticides currently used in large amounts, the insecticide chlorpyrifos (CLP) and the fungicide tebuconazole (TBZ). Their detailed uptake kinetics in the model earthworm species Eisenia andrei were measured in two arable soils differing in organic carbon content (1.02 and 1.93% respectively). According to our results, a steady state was reached after 3-5 days for both pesticides and soils. The values of bioaccumulation factors calculated at the steady state ranged from 4.5 to 6.3 for CLP and 2.2-13.1 for TBZ. Bioaccumulation factors were also calculated as the ratio of uptake and elimination rate constants with results comparable with steady-state bioaccumulation factors. The results suggested that the degradation and bioaccumulation of tested compounds might be influenced by other factors than only total organic carbon (e.g. clay content). The lower K and hydrophobicity of TBZ relative to CLP probably led to higher availability of TBZ through pore water exposure. On the other hand, CLP's higher hydrophobicity probably caused an increase in availability by its additional uptake via ingestion. To enable a proper ecological risk assessment of current pesticides in soils, it is necessary to accurately determine their bioaccumulation in soil invertebrates. We believe that our study not only brings such information for two specific pesticides but also addresses key methodological issues in this area.
农业今天与大量使用农药密不可分。尽管监管严格，但仍不能排除它们进入土壤的可能性，它们可能进入土壤生物和植物，并进一步进入陆地食物链。本研究旨在调查目前大量使用的两种农药，即杀虫剂毒死蜱（CLP）和杀菌剂戊唑醇（TBZ）的生物累积情况。在两种有机碳含量不同的耕地土壤（分别为 1.02%和 1.93%）中，对模式蚯蚓物种赤子爱胜蚓进行了详细的摄取动力学研究。根据我们的结果，两种农药和两种土壤在 3-5 天后均达到稳定状态。在稳定状态下计算的生物累积因子值范围为 CLP 的 4.5-6.3 和 TBZ 的 2.2-13.1。还计算了生物累积因子作为摄取和消除速率常数的比值，结果与稳定状态下的生物累积因子相当。结果表明，测试化合物的降解和生物累积可能受到总有机碳以外的其他因素的影响（例如粘土含量）。与 CLP 相比，TBZ 的降解和生物累积可能受到其他因素的影响，例如其较低的 K 值和疏水性，这可能导致 TBZ 通过孔隙水暴露而具有更高的可用性。另一方面，CLP 的较高疏水性可能通过额外的摄入而增加其可用性。为了对土壤中当前农药进行适当的生态风险评估，有必要准确确定它们在土壤无脊椎动物中的生物累积情况。我们相信，我们的研究不仅为两种特定农药提供了此类信息，而且还解决了该领域的关键方法学问题。
