Muna Marge, Heinlaan Margit, Blinova Irina, Vija Heiki, Kahru Anne
Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia; Department of Materials and Environmental Technology, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia.
Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia.
Environ Pollut. 2017 Dec;231(Pt 2):1488-1496. doi: 10.1016/j.envpol.2017.07.083. Epub 2017 Sep 28.
Toxicity of Cu and Cu-based nanoparticles (NPs) to aquatic biota is usually mitigated in natural freshwater compared to organics-free artificial freshwater. The main aim of this study was to evaluate whether mitigated toxicity is accompanied by lower total copper body burden in the freshwater crustacean Daphnia magna and whether CuO NPs are more hazardous in this aspect than soluble Cu salts. Total copper body burden in different media (OECD202 artificial freshwater and two natural freshwaters) was measured by a relatively novel technique - total reflection X-ray fluorescence (TXRF) spectroscopy - which proved suitable for the analysis of individual juvenile daphnids. Mean copper body burden was 2.8-42 times higher in daphnids exposed to CuO NPs (0.05 mg Cu/L and 1 mg Cu/L) than in daphnids exposed to equal or equitoxic concentrations (0.025 mg Cu/L and 0.05 mg Cu/L) of CuSO. Using natural freshwater instead of artificial one resulted in increased copper burden after exposure to CuO NPs but not after exposure to Cu salt. After 24 h post-exposure depuration in the presence of algae Raphidocelis subcapitata, total copper body burden in daphnids exposed to CuO NPs sharply decreased while in daphnids exposed to Cu salt it did not. Despite the CuO NP toxicity mitigating effect of natural freshwater, total copper body burden of aquatic crustaceans in natural waterbodies may be greater than could be predicted based on the results obtained using artificial freshwater as the test medium.
与无有机物的人工淡水相比，铜及铜基纳米颗粒（NPs）对水生生物群的毒性在天然淡水中通常会减轻。本研究的主要目的是评估毒性减轻是否伴随着淡水甲壳类动物大型溞体内总铜负荷的降低，以及在这方面氧化铜纳米颗粒是否比可溶性铜盐更具危害性。通过一种相对新颖的技术——全反射X射线荧光（TXRF）光谱法测量了不同介质（经合组织202人工淡水和两种天然淡水）中的总铜负荷，该技术被证明适用于分析单个幼年溞。暴露于氧化铜纳米颗粒（0.05毫克铜/升和1毫克铜/升）的溞体内平均铜负荷比暴露于同等或等效毒性浓度（0.025毫克铜/升和0.05毫克铜/升）硫酸铜的溞高2.8至42倍。使用天然淡水而非人工淡水会导致暴露于氧化铜纳米颗粒后铜负荷增加，但暴露于铜盐后则不会。在存在藻类小头隐藻的情况下暴露24小时后，暴露于氧化铜纳米颗粒的溞体内总铜负荷急剧下降，而暴露于铜盐的溞体内则没有。尽管天然淡水对氧化铜纳米颗粒有减轻毒性的作用，但天然水体中水生甲壳类动物的总铜负荷可能比使用人工淡水作为测试介质所获得的结果预测的要高。
