Bamfield Marine Science Centre, Bamfield, British Columbia, V0R 1B0, Canada; University of British Columbia, Department of Zoology, Vancouver, British Columbia, V6T 1Z4, Canada; CAPES Foundation, Ministry of Education of Brazil, Brasília, DF 70040-020, Brazil.
Bamfield Marine Science Centre, Bamfield, British Columbia, V0R 1B0, Canada; University of British Columbia, Department of Zoology, Vancouver, British Columbia, V6T 1Z4, Canada; Instituto Nacional de Pesquisas da Amazônia (INPA), Laboratório de Ecotoxicologia Aquática na Amazônia, Manaus, Amazonas, CEP 69067-375, Brazil.
Aquat Toxicol. 2021 Jan;230:105709. doi: 10.1016/j.aquatox.2020.105709. Epub 2020 Dec 3.
Metal accumulation, disturbance of Ca homeostasis, and occurrence of abnormalities are well-established consequences of single metal exposure during early development stages of sea urchins. However, the effects caused by low concentrations of metals and metal mixtures need to be better understood in marine invertebrates. Therefore, the present study investigated the effects of environmentally relevant concentrations of Zn (9 μg/L), Cd (30 μg/L) and Ni (5 μg/L) in single and binary exposures (Zn + Cd, Cd + Ni and Ni + Zn) to the early life stages of the purple sea urchin Strongylocentrotus purpuratus. Endpoints checked in all treatments after 48-h exposure were unidirectional metal influx rates, bioaccumulation, and Ca influx rates. Additionally, the presence of abnormal larvae and developmental delay was evaluated at 24 h, 48 h and 72 h of exposure. Unidirectional influx rates of all three metals were significantly higher than control background rates in all single exposures and binary mixtures, and were generally not different between them. Net accumulation (body burden) of both Zn and Cd increased significantly as a result of their respective single exposures, while Ni accumulation decreased considerably. When Zn or Cd were presented in binary exposures with other metals, the net accumulations of Zn or Cd were reduced relative to single exposures to these metals, whereas this did not occur for Ni accumulation. Thus, bioaccumulation proved to be a better metric than influx rate measurements to analyze metal competition at a whole organism level at these low metal concentrations. Short-term Ca influx also did not appear to be a sensitive metric, as the measured rates did not vary among all single and binary exposures, with the exception of a lower rate in Ni + Zn binary exposure. A critical aspect observed was the relationship between bioaccumulation versus influx measurements, which proved positive for Cd, but negative for Zn and Ni, demonstrating possible capacities for both Zn and Ni regulation by sea urchin larvae. Increases in larval abnormalities relative to controls occurred only after binary mixtures, starting at 48 h exposure and maintained until 72 h. However, delay of the sea urchin development by the presence of gastrula stage at 72 h exposure occurred in Zn and Ni single exposures and all metal mixtures, with very high abnormal development when Ni was present.
金属积累、钙稳态失调以及异常发生是海洋无脊椎动物早期发育阶段单一金属暴露的既定后果。然而，需要更好地理解低浓度金属和金属混合物造成的影响。因此，本研究调查了环境相关浓度的 Zn（9μg/L）、Cd（30μg/L）和 Ni（5μg/L）在单一和二元暴露（Zn+Cd、Cd+Ni 和 Ni+Zn）对紫色海胆 Strongylocentrotus purpuratus 早期生命阶段的影响。在 48 小时暴露后，所有处理组中检查的终点是单向金属流入率、生物积累和 Ca 流入率。此外，在暴露 24、48 和 72 小时时，还评估了异常幼虫的出现和发育延迟情况。在所有单一暴露和二元混合物中，三种金属的单向流入率均显著高于对照背景率，且彼此之间没有差异。由于各自的单一暴露，Zn 和 Cd 的净积累（体内负荷）显著增加，而 Ni 的积累则显著减少。当 Zn 或 Cd 与其他金属在二元混合物中出现时，与这些金属的单一暴露相比，Zn 或 Cd 的净积累减少，而 Ni 的积累则不会发生。因此，生物积累被证明是一种比流入率测量更好的指标，可用于在这些低金属浓度下分析整个生物体水平的金属竞争。短期 Ca 流入率似乎也不是一个敏感指标，因为在所有单一和二元暴露中，测量的速率没有变化，除了 Ni+Zn 二元暴露的速率较低。观察到的一个关键方面是生物积累与流入测量之间的关系，该关系对 Cd 呈正相关，但对 Zn 和 Ni 呈负相关，这表明 Zn 和 Ni 可能具有由海胆幼虫调节的能力。与对照相比，仅在二元混合物中观察到幼虫异常增加，从 48 小时暴露开始，并持续到 72 小时。然而，在 Zn 和 Ni 单一暴露和所有金属混合物中，在 72 小时暴露时出现了海胆发育的延迟，当 Ni 存在时，异常发育非常高。
