Silva Patrícia V, Silva Ana Rita R, Clark Nathaniel J, Vassallo Joanne, Baccaro Marta, Medvešček Neja, Grgić Magdalena, Ferreira Abel, Busquets-Fité Martí, Jurkschat Kerstin, Papadiamantis Anastasios G, Puntes Victor, Lynch Iseult, Svendsen Claus, van den Brink Nico W, Handy Richard D, van Gestel Cornelis A M, Loureiro Susana
Department of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
Department of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
Sci Total Environ. 2023 May 15;873:162160. doi: 10.1016/j.scitotenv.2023.162160. Epub 2023 Feb 11.
Mesocosms allow the simulation of environmentally relevant conditions and can be used to establish more realistic scenarios of organism exposure to nanoparticles. An indoor mesocosm experiment simulating an aquatic stream ecosystem was conducted to assess the toxicokinetics and bioaccumulation of silver sulfide nanoparticles (AgS NPs) and AgNO in the freshwater invertebrates Girardia tigrina, Physa acuta and Chironomus riparius, and determine if previous single-species tests can predict bioaccumulation in the mesocosm. Water was daily spiked at 10 μg Ag L. Ag concentrations in water and sediment reached values of 13.4 μg Ag L and 0.30 μg Ag g in the AgS NP exposure, and 12.8 μg Ag L and 0.20 μg Ag g in the AgNO. Silver was bioaccumulated by the species from both treatments, but with approximately 1.5, 3 and 11 times higher body Ag concentrations in AgNO compared to AgS NP exposures in snails, chironomids and planarians, respectively. In the AgS NP exposures, the observed uptake was probably of the particulate form. This demonstrates that this more environmentally relevant Ag nanoform may be bioavailable for uptake by benthic organisms. Interspecies interactions likely occurred, namely predation (planarians fed on chironomids and snails), which somehow influenced Ag uptake/bioaccumulation, possibly by altering organisms´ foraging behaviour. Higher Ag uptake rate constants were determined for AgNO (0.64, 80.4 and 1.12 L g day) than for AgS NPs (0.05, 2.65 and 0.32 L g day) for planarians, snails and chironomids, respectively. Biomagnification under environmentally realistic exposure seemed to be low, although it was likely to occur in the food chain P. acuta to G. tigrina exposed to AgNO. Single-species tests generally could not reliably predict Ag bioaccumulation in the more complex mesocosm scenario. This study provides methodologies/data to better understand exposure, toxicokinetics and bioaccumulation of Ag in complex systems, reinforcing the need to use mesocosm studies to improve the risk assessment of environmental contaminants, specifically NPs, in aquatic environments.
中宇宙实验能够模拟与环境相关的条件，可用于建立更符合实际情况的生物体接触纳米颗粒的场景。开展了一项模拟水生溪流生态系统的室内中宇宙实验，以评估硫化银纳米颗粒（AgS NPs）和硝酸银（AgNO₃）在淡水无脊椎动物——豹纹涡虫（Girardia tigrina）、急性膀胱螺（Physa acuta）和摇蚊（Chironomus riparius）体内的毒物动力学和生物累积情况，并确定之前的单物种测试是否能够预测中宇宙中的生物累积。每天以10 μg Ag/L的剂量向水中添加银。在AgS NPs暴露组中，水和沉积物中的银浓度分别达到13.4 μg Ag/L和0.30 μg Ag/g；在AgNO₃暴露组中，水和沉积物中的银浓度分别为12.8 μg Ag/L和0.20 μg Ag/g。两种处理中的物种均出现了银的生物累积，但在蜗牛、摇蚊和涡虫中，AgNO₃处理组的生物体内银浓度分别比AgS NPs暴露组高约1.5倍、3倍和11倍。在AgS NPs暴露组中，观察到的吸收可能是颗粒形式的。这表明这种与环境相关性更强的银纳米形式可能对底栖生物具有生物可利用性以供其吸收。种间相互作用可能发生了，即捕食行为（涡虫捕食摇蚊和蜗牛），这在某种程度上影响了银的吸收/生物累积，可能是通过改变生物体的觅食行为。对于涡虫、蜗牛和摇蚊，AgNO₃的银吸收速率常数分别为0.64、80.4和1.12 L/g·天，高于AgS NPs的吸收速率常数（分别为0.05、2.65和0.32 L/g·天）。在环境现实暴露条件下，生物放大作用似乎较低，尽管在暴露于AgNO₃的急性膀胱螺到豹纹涡虫的食物链中可能会发生生物放大。单物种测试通常无法可靠地预测在更复杂的中宇宙场景中的银生物累积情况。本研究提供了方法/数据，以更好地理解银在复杂系统中的暴露、毒物动力学和生物累积情况，强化了使用中宇宙研究来改进水生环境中环境污染物（特别是纳米颗粒）风险评估的必要性。
