Department of Biology, University of Aveiro, 3810-193 Aveiro, Portugal.
Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, 3810-193 Aveiro, Portugal.
Int J Environ Res Public Health. 2022 Nov 24;19(23):15610. doi: 10.3390/ijerph192315610.
Freshwater provides valuable services and functions to humankind. However, macroinvertebrates that underpin the delivery of many of those ecosystem services and functions are under an additional threat caused by microplastic pollution. Chironomids are one of the most abundant groups of macroinvertebrates in these environments and the most sensitive to microplastics. This investigation addressed the effects of polyurethane (PU-MPs; 7.0-9.0 µm) on the chironomid at the organism and sub-organism levels. For this purpose, two assays were carried out: (i) addressing the effects of PU-MPs on partial life cycle traits (larval size and emergence parameters) in a 28 d assay considering concentrations up to 750 mg/Kg, and (ii) larvae behaviour (locomotion) as well as the biochemical responses (oxidative damage, aerobic energy production, and energy reserves) in a 10 d assay considering an environmentally relevant concentration with no observed effects on previous life history traits (no observed effect concentration; NOEC = (375 mg/kg). Exposure to PU-MPs did not affect larval length nor cumulative and time to emergence. Conversely, when exposed to an environmentally relevant concentration for 10 days, contaminated larvae were revealed to be lighter (but not smaller nor less nutritionally affected in terms of energy reserves) and more active when foraging, which was reflected in the activation of their aerobic metabolism when assessing the electron transport chain as a proxy. Notwithstanding, PU-MPs did not originate observable energy costs, either on protein, lipid, or sugar contents on contaminated larvae, which may justify the absence of effects on larval growth and emergence. Therefore, the increased production of energy used for the locomotion and functioning of larvae was at the expense of the fraction of energy that should have been allocated for the weight of the individuals. A long-term exposure involving a multigenerational assessment would bring intel on the potential (cumulative) sub-lethal effects of PU-MPs on fitness.
淡水为人类提供了有价值的服务和功能。然而，支撑许多生态系统服务和功能的底层大型无脊椎动物正受到微塑料污染的额外威胁。摇蚊是这些环境中最丰富的大型无脊椎动物之一，对微塑料也最敏感。本研究调查了聚氨酯（PU-MPs；7.0-9.0 µm）对摇蚊个体和亚个体水平的影响。为此，进行了两项实验：（i）在 28 天的实验中，研究了 PU-MPs 对幼虫大小和成虫参数等部分生命周期特征的影响，实验考虑了高达 750 mg/Kg 的浓度；（ii）在 10 天的实验中，研究了幼虫行为（运动）以及生化反应（氧化损伤、有氧能量产生和能量储备），实验考虑了一个具有环境相关性的浓度，该浓度对之前的生活史特征没有影响（无观察到效应浓度；NOEC =（375 mg/kg）。暴露于 PU-MPs 不会影响幼虫长度或累积和成虫出现时间。相反，当幼虫在 10 天内暴露于环境相关浓度时，它们的体重会减轻（但不会更小或在能量储备方面受到营养影响），觅食时会更加活跃，这反映在评估电子传递链作为替代物时有氧代谢的激活。然而，污染幼虫的蛋白质、脂质或糖含量并未出现可观察到的能量消耗，这可能解释了对幼虫生长和成虫出现没有影响的原因。因此，用于幼虫运动和功能的能量增加是以个体体重应分配的能量为代价的。涉及多代评估的长期暴露将提供有关 PU-MPs 对适合度的潜在（累积）亚致死影响的信息。
