Assessment of the Heavy Metals Pollution and Ecological Risk in Sediments of Mediterranean Sea Drain Estuaries in Egypt and Phytoremediation Potential of Two Emergent Plants

Yasser A El-Amier,Bassem N Samra,Mohamed A El-Esawi,Armel Zacharie Ekoa Bessa,Wafaa K Kotb,Mohammad S Al-Harbi,Ashraf Elsayed

doi:10.3390/su132112244

Abstract

Environmental pollution and its eco-toxicological impacts have become a large and interesting concern worldwide as a result of fast urbanization, population expansion, sewage discharge, and heavy industrial development. Nine heavy metals (Pb, Cd, Fe, Mn, Zn, Ni, Cu, Cr, and Co) were evaluated in 20 sediment samples from the estuaries of four major drains along the Mediterranean shoreline (Nile Delta coast) to determine the possible ecological effect of high heavy metal concentrations as well as roots and shoots of two common macrophytes (Cyperus alopecuroides and Persicaria salicifolia). For sediment, single- and multi-elemental standard indices were used to measure ecological risk. Data revealed high contents of heavy metals, for which the mean values of heavy metals in sediment followed a direction of Fe > Mn > Co > Zn > Cu > Ni > Cr > Pb > Cd, Fe > Mn > Co > Ni > Zn > Cu > Cr > Pb > Cd and Fe > Mn > Zn > Co > Cu > Ni > Cr > Pb > Cd for drains stream, estuaries, and Mediterranean coast, respectively. Mn, Cr, Zn, and Pb were found to be within Canadian Soil Quality Guidelines (CSQGD) and U.S. Environmental Protection Agency Guidelines (US-EPA) limitations, except for Zn and Pb in drain streams, which were above the US-EPA limits, whereas Cd, Co, Cu, and Ni indicated a high ecological risk index. This high quantity of contaminants might be linked to unabated manufacturing operations, which can bio-accumulate in food systems and create significant health issues in people. C. alopecuroides root demonstrated a more efficient accumulation of all metals than the shoot system. For most heavy metals, C. alopecuroides had the highest root BAF levels with the exception of Ni and Pb in P. salicifolia. As a result, C. alopecuroides might be employed as a possible phytoextractor of these dangerous metals, while P. salicifolia could be used as a hyper-accumulator of Ni and Pb. The policymaker must consider strict rules and restrictions against uncontrolled industrial operations, particularly in the Nile Delta near water streams.

Highlights

IntroductionOn its journey through Egypt, a large portion of Egypt’s water is reused several times
Egypt’s water supply is supplemented significantly by agricultural drainage water
The current study discovered that enrichment coefficient (EF) varied little among the heavy metals studied; Mn and Ni had EFs more than unity (1.43 and 1.02, respectively) in P. salicifolia but only Ni (1.76) in C. alopecuroides

Summary

Introduction

On its journey through Egypt, a large portion of Egypt’s water is reused several times. Human settlements intensify pollution problems because drainage systems receive large amounts of nutrients, such as waste disposal from urban and industrial 4.0/). Sustainability 2021, 13, 12244 centres [2,3]. Heavy metals are one of the most studied environmental contaminants because they may cause human health issues, powerful neurotoxins in fish, and a detrimental influence on the marine ecology, all of which are harmful to communities and biological resources [4,5]. The protection of resources of water has led to a policy of sanitation development in urban areas, with the majority of cities equipped. The deficit in rural areas continues to be a major concern for the industry [6]

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