Department of Biology, School of Science, Pennsylvania State University, The Behrend College, Erie, PA, 16563, USA.
Department of Biology, School of Science, Pennsylvania State University, The Behrend College, Erie, PA, 16563, USA.
Chemosphere. 2023 Dec;345:140492. doi: 10.1016/j.chemosphere.2023.140492. Epub 2023 Oct 19.
Non-target organisms in aquatic environments may experience lethal or sublethal effects following exposure to contaminants. Most protocols and regulations, however, are designed to provide protection from lethal effects and are thus based on conventional estimates of population lethality. The relative lack of reliable behavioral endpoints makes it challenging to implement regulations that are similarly protective against sublethal toxicity. The objective of this study was to quantify the avoidance behavior of Hyalella azteca when exposed to three insecticides-bifenthrin (B), chlorpyrifos (C), and permethrin (P)-at a range of estimated lethal concentrations. A two-choice behavioral arena was used for each chemical to quantify H. azteca activity and time spent in either uncontaminated sediment or sediment spiked at concentrations reflecting estimated 48-h lethal concentrations (LC, LC, and LC). For all three insecticides, naïve H. azteca demonstrated a preference for the uncontaminated sediment over the contaminated sediment at the LC (B: 312 ng/g; C: 1265 ng/g; P: 5042 ng/g) and LC (B: 230 ng/g; C: 859 ng/g; P: 3817 ng/g), spending significantly more time in the uncontaminated side of the arena. H. azteca did not avoid sediment at LC (B: 204 ng/g; C: 609 ng/g; P: 1515 ng/g) levels, indicating the existence of a potential threshold of detection. Despite the lack of substrate preference at this exposure level, H. azteca were nevertheless more active (i.e., increased zone-switching) when exposed to bifenthrin at the LC, suggesting a possible irritation response (e.g., movement after exposure) to this chemical. Our results provide evidence that H. azteca exhibit innate avoidance responses to sediments contaminated with common insecticides at concentrations below those represented by traditional toxicological endpoints (e.g., LC). The sensitivity and ease with which this behavioral endpoint can be assayed demonstrates the potential utility of behavioral endpoints in toxicological assessments using model organisms.
水生环境中的非目标生物在接触污染物后可能会产生致死或亚致死效应。然而，大多数协议和法规旨在提供对致死效应的保护，因此是基于对种群致死率的传统估计。由于缺乏可靠的行为终点，因此难以实施同样能防止亚致死毒性的法规。本研究的目的是量化食蚊鱼在接触三种杀虫剂-联苯菊酯（B）、毒死蜱（C）和氯菊酯（P）时的回避行为，这些杀虫剂的浓度范围估计为致死浓度。为每种化学物质使用了一个双选择行为竞技场来量化 H.azteca 的活动和在未受污染的沉积物或浓度反映估计的 48 小时致死浓度（LC、LC 和 LC）的受污染沉积物中花费的时间。对于所有三种杀虫剂，在 LC（B：312ng/g；C：1265ng/g；P：5042ng/g）和 LC（B：230ng/g；C：859ng/g；P：3817ng/g）时，未接触过杀虫剂的 H.azteca 对未受污染的沉积物表现出明显的偏好，在竞技场的未受污染侧花费的时间明显更多。H.azteca 在 LC（B：204ng/g；C：609ng/g；P：1515ng/g）水平下没有避免沉积物，这表明存在潜在的检测阈值。尽管在暴露水平下没有基质偏好，但在 LC 暴露时，H.azteca 仍然更加活跃（即增加了区域切换），这表明对这种化学物质可能存在刺激反应（例如，暴露后的运动）。我们的研究结果表明，H.azteca 在接触低于传统毒理学终点（例如 LC）代表的浓度的常见杀虫剂污染的沉积物时表现出先天的回避反应。该行为终点的敏感性和易于测定表明，该行为终点在使用模式生物进行毒理学评估中的潜在效用。
