Department of Zoology, Faculty of Science, Ain Shams University, Khalifa El-Maamon St., El-Qobba Bridge, Cairo, 11566, Egypt.
Department of Animal and Poultry Physiology, Desert Research Center, Cairo, Egypt.
Environ Sci Pollut Res Int. 2020 Jun;27(18):23015-23025. doi: 10.1007/s11356-020-08736-x. Epub 2020 Apr 23.
This work aimed at using Little Egrets (Egretta garzetta), for the first time in Egypt, as a bioindicator of heavy metal contamination from three different Egyptian land use types (Qillin within Kafr El-Sheikh (S1, agricultural), Toukh within Qalyubia (S2, semi-rural area), and Abu Rawash within Giza (S3, urban)). Concentrations of aluminum (Al), barium (Ba), cobalt (Co), cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn) were analyzed in liver and kidney samples of twenty-six adult Little Egrets collected from the three localities during winter 2018. Moreover, the study calculated the Metal Pollution Index (MPI) to highlight the health of the surrounding environment using birds' internal organs as a mirror. Results revealed that, throughout the three sampling sites, the total metal concentrations in liver samples exceeded that of the kidney, indicating that the liver is the target organ of metal accumulation. The Little Egret's liver was found to be the best-recommended organ to use in future biomonitoring of Cu, Zn, Fe, Mn, and Ni, whereas Al, Co, Cr, Ba, Pb, and Cd can be monitored in the kidney. Cu and Pb were higher in the Little Egret's tissues collected from the agricultural site (S1), whereas Ba, Ni, and Fe were higher in the semi-rural site (S2), followed finally by Cd in the urbanized site (S3). The concentrations of trace elements reported in Little Egrets were within the known background level for water birds. However, alarming concentrations were found for Ni levels in liver (from Qillin and Toukh), as well as Pb and Cr levels in kidney samples (from the three localities). MPI of the eleven studied metals in both liver and kidney of the studied species decreased in the order Qillin (24.36) > Abu Rawash (17.98) > Toukh (3.90). In the three investigated localities, the overall calculated MPI values were higher than one, indicating that the ecosystem is polluted. The study suggested using Little Egrets as a bioindicator of metal contamination.
本研究首次在埃及以小白鹭（Egretta garzetta）为研究对象，通过分析来自埃及三种不同土地利用类型（Kafr El-Sheikh 的 Qillin（S1，农业区）、Qalyubia 的 Toukh（S2，半农村地区）和 Giza 的 Abu Rawash（S3，城市地区））的 26 只成年小白鹭肝脏和肾脏样本中的铝（Al）、钡（Ba）、钴（Co）、镉（Cd）、铬（Cr）、铜（Cu）、锰（Mn）、铁（Fe）、镍（Ni）、铅（Pb）和锌（Zn）浓度，以此来评估这些地区的重金属污染情况。此外，本研究还计算了金属污染指数（MPI），以利用鸟类内脏作为“镜子”来反映周围环境的健康状况。结果表明，在所研究的三个采样点中，肝脏样本中的总金属浓度均高于肾脏，表明肝脏是金属积累的靶器官。小白鹭的肝脏是未来监测 Cu、Zn、Fe、Mn 和 Ni 的最佳推荐器官，而 Al、Co、Cr、Ba、Pb 和 Cd 则可以在肾脏中监测到。在农业区（S1）采集的小白鹭组织中，Cu 和 Pb 的含量较高，而在半农村区（S2）中，Ba、Ni 和 Fe 的含量较高，最后在城市化地区（S3）中 Cd 的含量较高。小白鹭组织中检测到的微量元素浓度处于水鸟已知的背景水平范围内。然而，在肝脏（来自 Qillin 和 Toukh）中 Ni 的浓度、以及在肾脏样本中 Pb 和 Cr 的浓度（来自三个研究地点）均达到了令人担忧的水平。在所研究的 11 种金属中，在肝脏和肾脏中 MPI 的顺序为 Qillin（24.36）>Abu Rawash（17.98）>Toukh（3.90）。在所研究的三个地区，生态系统的整体计算 MPI 值均高于 1，表明生态系统受到了污染。本研究建议使用小白鹭作为金属污染的生物指标。
