Veterinary Integrative Biosciences Department, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
Environ Toxicol Chem. 2020 Mar;39(3):517-525. doi: 10.1002/etc.4642. Epub 2020 Jan 22.
Widespread use of pesticides has resulted in the accumulation of pesticide residues in the environment due to their persistence and stability. To reduce potential exposures, we have developed broad-acting clay-based sorbents that can be included in the diet as enterosorbents to reduce the bioavailability and toxicity of chemicals. In the present study, parent and acid-processed calcium montmorillonite clays (CM and APM, respectively) were used to determine their potential as sorbents of the organochlorine insecticide dieldrin. We used adsorption isotherms, thermodynamics, and dosimetry studies to determine the capacities and affinities of the clays, the enthalpies of the binding reactions, and potential doses of sorbent that could protect against high exposures. Adsorption isotherms for APM fit a Langmuir model with high enthalpy (suggesting chemisorption) and high capacity (Q value = 0.45 mol kg ), indicating tight binding of dieldrin. Cultures of Hydra vulgaris were used to determine the ability of sorbents to protect a living organism from dieldrin toxicity. The inclusion of acid-processed clays resulted in the highest reduction of dieldrin toxicity (70%) in the hydra. Further work indicated that both CM and APM can significantly reduce the bioavailability of dieldrin from soil (p ≤ 0.01). These results suggest that APM (and similar clays) can be effective sorbents of dieldrin and may be included in the diet and/or soil to protect against environmental exposures. Environ Toxicol Chem 2020;39:517-525. © 2019 SETAC.
广泛使用农药会导致其在环境中积累残留，这是由于它们的持久性和稳定性所致。为了降低潜在的暴露风险，我们开发了广谱粘土基吸附剂，可以将其作为肠内吸附剂添加到饮食中，以降低化学物质的生物利用度和毒性。在本研究中，使用原土和酸处理钙蒙脱石粘土（分别为 CM 和 APM）来确定它们作为有机氯杀虫剂狄氏剂吸附剂的潜力。我们使用吸附等温线、热力学和剂量学研究来确定粘土的容量和亲和力、结合反应的焓以及可以防止高暴露的潜在吸附剂量。APM 的吸附等温线符合朗缪尔模型，具有高热焓（表明化学吸附）和高容量（Q 值=0.45 mol kg-1），表明狄氏剂的紧密结合。水螅的培养物用于确定吸附剂保护生物体免受狄氏剂毒性的能力。添加酸处理粘土可使水螅的狄氏剂毒性降低 70%（最高）。进一步的研究表明，CM 和 APM 均可显著降低土壤中狄氏剂的生物利用度（p≤0.01）。这些结果表明，APM（和类似的粘土）可以作为狄氏剂的有效吸附剂，并且可以包含在饮食中和/或土壤中，以防止环境暴露。Environ Toxicol Chem 2020;39:517-525。©2019 SETAC。
