Abdallah Maha Ahmed Mohamed
National Institute of Oceanography and Fisheries, NIOF, Cairo, Egypt.
Mar Pollut Bull. 2025 Mar;212:117478. doi: 10.1016/j.marpolbul.2024.117478. Epub 2024 Dec 28.
The highly industrialized areas characterize the delta coasts of the world, due to the discharging of large quantity of wastewater into the river estuaries. The entrance of phenolic compounds and PAHs into the aquatic environment has not been sufficiently studied on the Egyptian Mediterranean coast. The article examines the content and ecological risks associated with 11 phenolic compounds and 14 PAHs in the bottom sediments of the Nile River estuaries, the largest river systems that discharged into the Mediterranean Sea.
Phenolic and PAHs compounds concentrations were determined by high-performance liquid chromatography (HPLC) and GC MS (Hewlett-Packard 5889B MS 'Engine') respectively. The total concentration of 11 phenolic compounds (∑PC11) in sediment ranged from undetected to 272.48 μg/g with an average of 7.95 μg/g. For individual phenolic compound, the mean concentration of 4-nitrophenol was the highest in sediment (33.32 μg/g). The total concentration of nonchlorophenols (∑NCP6) was significantly higher than that of 5 chlorophenols (∑CP5) in all areas. The concentrations of total PAHs ranged between 12,198 to 26,551 ng/g, with an average of 22,009 ng/g. PAH levels have increased in the two estuaries under the influence of riverine inputs from the Nile River. LMW are clearly predominant over HMW (ratio is between 0.7 and 1.18) in the most sediment. The LMW/HMW ratio ranged between 0.23 and 0.39, indicating both pyrolytic and petrogenic sources. The total concentration of potentially carcinogenic PAHs (∑PAH7) ranged from 5049 to 15,144 ng/g. The rest individuals including Acy, Ace, Phe, Flu, BaA, BaP and DahA were (≥ERM) suggesting frequently harmful biological impairments.
The highest concentrations of phenols and PAHs in the surface sediment occurred in the lower reach of the drainage outlets and land-based sources, suggesting that these pollutants accumulated along with runoffs from the input of the pollutants into the aquatic environment. The risk quotient reveals high ecological risks of the total phenolic and PAHs compounds in sediment. Thus, it is imperative to control the discharge of wastewater into the river so as to reduce the potential risks from phenols off Nile Delta sediments to the marine environment and consequently to humans.
世界上的三角洲海岸以高度工业化地区为特征，这是由于大量废水排放到河口所致。在埃及地中海沿岸，酚类化合物和多环芳烃进入水生环境的情况尚未得到充分研究。本文研究了尼罗河河口（流入地中海的最大河流系统）底部沉积物中11种酚类化合物和14种多环芳烃的含量及其生态风险。
分别采用高效液相色谱法（HPLC）和气相色谱 - 质谱联用仪（惠普5889B质谱“引擎”）测定酚类和多环芳烃化合物的浓度。沉积物中11种酚类化合物的总浓度（∑PC11）范围为未检测到至272.48μg/g，平均为7.95μg/g。对于单个酚类化合物，沉积物中4 - 硝基苯酚的平均浓度最高（33.32μg/g）。在所有区域，非氯酚的总浓度（∑NCP6）显著高于5种氯酚的总浓度（∑CP5）。多环芳烃的总浓度在12,198至26,551 ng/g之间，平均为22,009 ng/g。在尼罗河河水输入的影响下，两个河口的多环芳烃水平有所增加。在大多数沉积物中，低分子量多环芳烃明显比高分子量多环芳烃占优势（比例在0.7至1.18之间）。低分子量/高分子量的比例在0.23至0.39之间，表明同时存在热解源和石油源。潜在致癌多环芳烃的总浓度（∑PAH7）范围为5049至15,144 ng/g。其余包括苊、蒽、菲、芴、苯并[a]蒽、苯并[a]芘和二氢苊的个体（≥ERM）表明经常存在有害的生物损害。
表层沉积物中酚类和多环芳烃的最高浓度出现在排水口下游和陆源，这表明这些污染物随着污染物径流输入到水生环境中而积累。风险商数显示沉积物中总酚类和多环芳烃化合物具有很高的生态风险。因此，必须控制废水向河流的排放，以降低尼罗河三角洲沉积物中酚类物质对海洋环境进而对人类造成的潜在风险。
