Du Chaoyi, Ding Ping, Guo Hongzhi, Gu Yulun, Shi Xuefang, Ni Yuyang, Zhu Shiyin, Zhang Lijuan, Chen Haibo, Qi Jianying
College of Biology and Environmental Sciences, Jishou University, Jishou 416000, People's Republic of China; State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China.
State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China.
Aquat Toxicol. 2025 Nov;288:107560. doi: 10.1016/j.aquatox.2025.107560. Epub 2025 Sep 1.
Microplastics (MPs) have emerged as ubiquitous environmental contaminants, while thallium (Tl), a highly toxic metalloid, is gaining attention as a novel pollutant due to its increasing release from electronic waste and mining activities. These pollutants frequently coexist in aquatic environments; however, their combined effects at environmentally relevant concentrations remain poorly understood. In this study, the adsorption behavior and joint neurotoxicity of polystyrene (PS) microplastics and Tl were systematically evaluated using Caenorhabditis elegans as a model organism. Adsorption kinetics followed both pseudo-first-order and pseudo-second-order models, yielding maximum Tl adsorption capacities of 66.682 µg/g and 67.981 µg/g, respectively. Adsorption efficiency declined with increasing salinity but was enhanced by higher pH, temperature, and humic acid (HA) concentrations. Neurotoxicity assays were conducted using Tl at 0.01 and 0.1 μg/L, along with PS at corresponding Tl-saturated adsorption concentrations (147 and 1470 μg/L). Behavioral analysis revealed that PS significantly amplified Tl-induced neurotoxicity, as evidenced by reductions in head thrashes and body bends. Co-exposure led to pronounced neurodegeneration and altered fluorescence intensity in serotonergic, GABAergic, and glutamatergic neurons in transgenic nematodes. Additionally, neurotransmitter levels were markedly decreased, and the expression of key neurofunctional genes (e.g., mod-1, tph-1, and unc-46) was significantly dysregulated. Collectively, these findings demonstrate that PS microplastics potentiate the neurotoxic effects of Tl by disrupting multiple neurotransmission pathways, underscoring the ecological risks associated with the co-occurrence of MPs and heavy metals in the environment.
微塑料（MPs）已成为无处不在的环境污染物，而铊（Tl）作为一种剧毒类金属，因其从电子废物和采矿活动中的释放量不断增加，正作为一种新型污染物受到关注。这些污染物在水生环境中经常共存；然而，在环境相关浓度下它们的联合效应仍知之甚少。在本研究中，以秀丽隐杆线虫为模式生物，系统评估了聚苯乙烯（PS）微塑料和铊的吸附行为及联合神经毒性。吸附动力学符合准一级和准二级模型，铊的最大吸附容量分别为66.682μg/g和67.981μg/g。吸附效率随盐度增加而下降，但随pH值升高、温度升高和腐殖酸（HA）浓度增加而提高。使用0.01和0.1μg/L的铊以及相应铊饱和吸附浓度（147和1470μg/L）的PS进行神经毒性试验。行为分析表明，PS显著放大了铊诱导的神经毒性，头部摆动和身体弯曲减少证明了这一点。共同暴露导致转基因线虫中血清素能、γ-氨基丁酸能和谷氨酸能神经元出现明显的神经变性并改变荧光强度。此外，神经递质水平显著降低，关键神经功能基因（如mod-1、tph-1和unc-46）的表达明显失调。总的来说，这些发现表明PS微塑料通过破坏多种神经传递途径增强了铊的神经毒性作用，强调了环境中微塑料和重金属共存所带来的生态风险。
