阿斯旺建坝后尼罗河三角洲泻湖重金属污染特征及其环境意义

本研究以尼罗河三角洲泻湖(Manzala、Burullus、Edku)为典型区域,利用6根浅孔并选取Al、Cd、Cr、Fe、Mn、Pb、Cu、Zn等主要重金属元素,探讨了自然和人类活动(建坝)共同作用下河口泻湖湿地环境重金属时空分布及污染来源。研究结果表明,1964年阿斯旺建坝和海岸保护工程实施后,泻湖地区逐渐演变为稳定而封闭的沉积环境。钻孔上层(10~15 cm)沉积物重金属富集现象反映了建坝后三角洲泻湖环境污染加重。重金属空间分布表现为平原东西部Manzala和Edku湖污染较重,而中部的Burullus湖污染较轻。相关性分析和富集系数(EF)变化进一步揭示Manzala湖特征污染元素为Pb、Cu、Zn和Cd,污染源主要来自开罗石油化工等产业废水;Burullus湖特征污染元素为Mn和Pb,应该与湖区附近农业废水的大量排放有关;Edku湖特征污染元素则为Mn、Pb和Zn,其重金属可能来自邻近的Abu-Qir湾带来的亚历山大工业废水。     

Determination of Acaricide Residues in Saudi Arabian Honey and Beeswax Using Solid Phase Extraction and Gas Chromatography

Determination of acaricide residues of flumethrin, tau-fluvalinate, coumaphos, and amitraz in honey and beeswax was carried out using a rapid extraction method utilizing C-18 SPE cartridges and an analytical method utilizing GC with ECD, NPD, and MSD detectors for the four acaricides. Recovery percentages from the extraction method ranged from 90–102%, while the minimum detection levels ranged from 0.01–0.05 mg/kg for the acaricides. Nine of the 21 analyzed samples were found to be contaminated with the acaricides tau-fluvalinate and coumaphos. Neither flumethrin nor amitraz was detected in any of the honey or wax samples. Coumaphos was found only in honey samples in which two samples exceeded the tolerance levels set by EPA and EC regulations. It has not been detected in beeswax. Five honey samples and eight beeswax samples were found to be contaminated with tau-fluvalinate. One of the wax samples was contaminated with a relatively high residue of tau-fluvalinate and contained above 10 mg/kg.