Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada.
Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
Environ Toxicol Chem. 2023 Jul;42(7):1553-1563. doi: 10.1002/etc.5637. Epub 2023 May 19.
The accumulation and tissue distribution of toxicants in aquatic biota can be determinative of their toxic impact to both exposed organisms and their potential human consumers. In the present study, accumulation of the trace metal thallium (Tl) in gill, muscle, plasma, and otoliths of rainbow trout (Oncorhynchus mykiss) following acute (96-h) and subchronic (28-day) waterborne exposures was investigated. Owing to known interactions between Tl and potassium ions (K ), plasma and muscle K concentrations were also determined. Branchial Tl accumulated in a dose-dependent manner in both acute and subchronic exposures, while plasma Tl was rapidly mobilized to tissues and accumulated only at exposure concentrations of 141 µg L or higher. For muscle tissue, Tl concentrations at 28 days were markedly lower than those at 96 h at comparable exposure concentrations (0.9 µg L ), indicating the presence of mechanisms that act to reduce Tl accumulation over time. However, after acute exposure, muscle Tl reached concentrations that, if consumed, would exceed acceptable daily intake values for this element, indicating some risk to human health from the consumption of fish from waters heavily contaminated with Tl. Otoliths showed Tl concentrations that reflected exposure concentration and length, confirming their capacity to provide insight into fish exposure history. No changes in tissue K concentrations were observed, suggesting that accumulation of Tl in rainbow trout plasma and muscle does not occur at the expense of K homeostasis. In addition to highlighting the capacity of rainbow trout to accumulate Tl to levels that exceed recommended dietary doses to human consumers, the present study provides the first data of tissue-specific Tl accumulation in an important regulatory species. Environ Toxicol Chem 2023;42:1553-1563. © 2023 SETAC.
有毒物质在水生生物体内的积累和组织分布可以决定其对暴露生物及其潜在人类消费者的毒性影响。在本研究中，研究了急（96 小时）和亚急（28 天）水暴露后，虹鳟鱼（Oncorhynchus mykiss）鳃、肌肉、血浆和耳石中痕量金属铊（Tl）的积累情况。由于 Tl 与钾离子（K）之间已知存在相互作用，因此还测定了血浆和肌肉中的 K 浓度。在急性和亚急暴露中，鳃组织中的 Tl 呈剂量依赖性积累，而血浆 Tl 迅速向组织中转移，仅在暴露浓度为 141µg/L 或更高时才会积累。对于肌肉组织，在可比暴露浓度下，28 天时的 Tl 浓度明显低于 96 小时时的浓度（0.9µg/L），表明存在随着时间推移减少 Tl 积累的机制。然而，在急性暴露后，肌肉 Tl 达到了如果食用就会超过该元素可接受日摄入量值的浓度，这表明从 Tl 污染严重的水域中捕捞的鱼类对人类健康存在一定风险。耳石中的 Tl 浓度反映了暴露浓度和时间，证实了它们能够提供鱼类暴露历史的洞察力。未观察到组织 K 浓度的变化，这表明 Tl 在虹鳟鱼血浆和肌肉中的积累不会影响 K 体内平衡。本研究不仅强调了虹鳟鱼积累 Tl 的能力，使其超过了人类消费者推荐膳食剂量，还提供了重要监管物种中组织特异性 Tl 积累的首批数据。环境毒理化学 2023；42：1553-1563。版权所有 © 2023 SETAC。
