Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Sediments of Lake Manzala, Egypt

Abstract

This investigation represents the first extensive study of the spatial distribution, sources, and potential effects of polycyclic aromatic hydrocarbons (PAHs) in sediments from Lake Manzala, the largest of Egypt's Mediterranean coastal lakes. The concentrations of PAHs (Σ39 components) ranged from 246 to 9910 ng g⁻¹ dry wt., the highest values corresponding to urban hotspots with high anthropogenic input coming from wastewater discharges and combustion activities and decreasing offshore. The levels of PAHs were significantly lower compared to values reported in several coastal/estuarine areas (e.g., in Spain, Italy, USA, and Egypt) receiving substantial anthropogenic inputs from urban and industrial activities. Source ratios indicated that the PAHs were mainly from petrogenic sources in near-shore urban hotspots, with higher contributions of pyrolytic sources in coastal and offshore areas which are little influenced by human activities. Sediment quality guidelines (SQGs) showed that except at one station heavily impacted by sewage discharge, the total and individual PAH concentrations were below effect range low (ERL) concentrations that are not likely to adversely affect benthic biota.

Keywords:

• PAHs
• Lake Manzala
• sediments
• source ratios
• sediment quality guidelines

Acknowledgement

The study was funded by the U.S.–Egypt 638 Joint Board on Scientific and Technological Cooperation, 639 USDA/FAS/ICD/RESD Project Number 58-3148-3-067. The detailed and concise reviews of the referee are much appreciated and made significant contributions to the improvement of the original manuscript.