Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing, China.
National Institute of Public Health and the Environment, Center for the Safety of Substances and Products, Bilthoven, The Netherlands.
Environ Toxicol Chem. 2018 May;37(5):1367-1377. doi: 10.1002/etc.4076. Epub 2018 Mar 1.
The transfer of the toxic heavy metal Cd from duckweed (Lemna minor L.) to the freshwater fish tilapia (Oreochromis mossambicus) was investigated. Concentrations of Cd in different chemical forms in duckweed and in different tissues (gut, edible muscle, and remnants or residual) of tilapia (i.e., ethanol-extractable fraction [F ], HCl-extractable fraction [F ], and residual fraction [F ]) were quantified, and the bioaccumulation factors (BAFs) of Cd in the tilapia body were calculated. Simple linear regression analysis was used to unravel the correlation and accumulation mechanisms of Cd along the short food chain. Our results showed that with increasing exposure concentrations of Cd (0-50 μM for duckweed and 0-10 μM for tilapia), the total, F (F )-, F (F )-, and F (F )-Cd concentrations in duckweed and different tissues of tilapia increased progressively. The Cd sources (aqueous or dietary) influenced the BAF for Cd accumulation in the whole body of tilapia. Furthermore, regression analyses yielded significant positive correlations (R > 0.96) between the Cd concentration in duckweed and in both the 3 parts and the whole body of tilapia. This finding suggests that Cd transfer from duckweed to tilapia can be quantitatively evaluated when tilapia is exposed only to duckweed. In addition, the linear regression between Cd accumulation in whole tilapia and F -, F -, and F -Cd showed that particularly the correlation with F -Cd is statistically significant (p < 0.001). The accumulated Cd concentrations and chemical forms in tilapia tissues also positively correlated with Cd sources (solution or duckweed). Compared with waterborne exposure only, duckweed especially increased the accumulation of Cd in the gut of tilapia. Taken together, our findings support a strong dependence of Cd accumulation and transfer from duckweed to tilapia on its chemical forms, especially on F -Cd. This knowledge may expedite more accurate risk assessment of heavy metals through aquatic food chain ecosystems. Environ Toxicol Chem 2018;37:1367-1377. © 2018 SETAC.
研究了有毒重金属 Cd 从浮萍（Lemna minor L.）向淡水鱼罗非鱼（Oreochromis mossambicus）的转移。定量分析了浮萍中 Cd 的不同化学形态以及罗非鱼不同组织（肠道、可食用肌肉和残余物或残留组织）中的 Cd 浓度（即乙醇提取部分[F ]、盐酸提取部分[F ]和残余部分[F ]），并计算了 Cd 在罗非鱼体内的生物积累因子（BAF）。简单线性回归分析用于揭示沿短食物链的 Cd 相关性和积累机制。研究结果表明，随着 Cd 暴露浓度的增加（浮萍为 0-50 μM，罗非鱼为 0-10 μM），浮萍和罗非鱼不同组织中总 Cd、F （F ）-、F （F ）-和 F （F ）-Cd 浓度均呈递增趋势。Cd 来源（水相或膳食）影响罗非鱼全身 Cd 积累的 BAF。此外，回归分析得到浮萍和罗非鱼 3 个部位及全身 Cd 浓度之间存在显著正相关（R > 0.96）。这表明当罗非鱼仅暴露于浮萍时，可以定量评估浮萍向罗非鱼的 Cd 转移。此外，在整个罗非鱼体内 Cd 积累与 F 、F 和 F -Cd 之间的线性回归显示，与 F -Cd 的相关性具有统计学意义（p < 0.001）。罗非鱼组织中 Cd 的积累浓度和化学形态也与 Cd 来源（溶液或浮萍）呈正相关。与仅水相暴露相比，浮萍尤其增加了罗非鱼肠道中 Cd 的积累。综上所述，本研究结果支持 Cd 从浮萍向罗非鱼的积累和转移强烈依赖于其化学形态，尤其是 F -Cd。这一知识可能会加速通过水生食物链生态系统对重金属进行更准确的风险评估。环境毒理化学 2018；37：1367-1377。©2018 SETAC。
