RESEARCH ARTICLE Metals in a northern Nile Delta lake: water, suspended particulates, sediments, and biota Mohamed A. Okbah 1 & Ahmed M. Abdelhalim 1 & Mohamed A. Abu El-Regal 2 & Naglaa F. Soliman 3,4 & Mohammed E. M. Nassar 2 Received: 25 April 2018 /Accepted: 25 September 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Lake Edku is one of the important fishing areas in the Nile Delta. It is exposed to different quantities of serious pollutants in particular metals. To overall appraise the risk and status of metals in the lake, a comprehensive study of total concentrations of cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), and zinc (Zn) in sediments and spatial- temporal variations of these metals in the dissolved and suspended particulates, and some tissues of Tilapias niloticus, was conducted from ten sampling sites during 2016. Results showed that none of the investigated metals exceeded the limits considered as hazardous for aquatic life in water. The highest concentrations of Cd, Cu, Ni, and Zn were observed in suspended particulate matter, which may precipitate on the surface of the sediments. Potential ecological risk analysis of the majority of the investigated metals in the sediment indicated that Lake Edku posed a low ecological risk. The estimated values of all metals in tissues of Tilapia niloticus were below the international permissible limits. Moreover, the potential risk of metals to human via the consumption of Tilapia niloticus was estimated using the weekly intake levels, which was lower than the WHO’ s safe provisional tolerant weekly intake levels. These results prove the importance of performing measurements of contaminants in various compartments of Lake Ecosystem including sediment, biota, and suspended particulate matter for proper management. Keywords Lake Edku . Sediments . Suspended particulates . Tilapia niloticus . Bio-accumulation factor . Potential ecological risk Introduction Lakes are essential water resources and ecosystems. They play important roles in a region’ s water supply, climate regulation, flood security, and biodiversity conservation (Hansen 2012). Accordingly, lakes are one of the most versatile ecosystems in the globe (Hu et al. 2012). Recently, contaminants have been released into lake environments from several anthropogenic sources (Shuhaimi-Othman 2008; Bing et al. 2011), particu- larly urban development and agricultural activities (Galbraith and Burns, 2007; Liu and Li 2011). Among the various types of contaminants, metals in aquatic environments have attracted considerable attention. Their environmental persis- tence and biological accumulation pose potential adverse ef- fects on biota (Birch and Apostolatos 2013; Yi et al. 2011) and can increase anthropogenic loading in aquatic environments (Liu et al. 2012). Metal concentrations in aquatic ecosystems are commonly monitored by measuring their levels in water, sediments, and biota (Camusso et al. 1995). In addition to water analysis performed over many years, sediment analysis is important in evaluating the qualities of an ecosystem, as this analysis reveals the long-term quality situation independent of current inputs (Adeyemo et al. 2008), and sediments are the final sink of contaminants in an aquatic system (Davies and Abowei 2009). On the other hand, monitoring of metal Responsible editor: Severine Le Faucheur Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11356-018-3337-8) contains supplementary material, which is available to authorized users. * Naglaa F. Soliman naglaa_farag2007@yahoo.com 1 Marine Chemistry Department, National Institute of Oceanography and Fisheries, Alexandria, Egypt 2 Marine Science Department, Faculty of Science, Port Said University, Port Said, Egypt 3 Department of Environmental Studies, Institute of Graduate Studies and Research, Alexandria University, Alexandria, Egypt 4 Technology Management Department, Egypt-Japan University of Science and Technology (E-JUST), P.O. Box 179, New Borg El-Arab City, Alexandria 21934, Egypt Environmental Science and Pollution Research https://doi.org/10.1007/s11356-018-3337-8