Department of Aquatic Environment, Faculty of Fish Resources, Suez University, Suez, Egypt,
Environ Monit Assess. 2014 Jun;186(6):3567-79. doi: 10.1007/s10661-014-3639-3. Epub 2014 Feb 12.
In risk assessment of aquatic sediments, the immobilizing effect of acid-volatile sulfide (AVS) on trace metals is a principal control on availability and associated toxicity of metals to aquatic biota, which reduces metal bioavailability and toxicity by binding and immobilizing metals as insoluble sulfides. Spatial variation pattern of AVS, simultaneously extracted metals (SEM), and sediment characteristics were studied for the first time in surface sediment samples (0-20 cm) from 43 locations in Egyptian northern delta lagoons (Manzalah, Burullus, and Maryut) as predictors of the bioavailability of some divalent metals (Cu, Zn, Cd, Pb, and Ni) in sediments as well as indicators of metal toxicity in anaerobic sediments. The results indicated that the ∑SEM (Cu + Zn + Cd + Pb + Ni) values in sediments of lagoon Burullus had higher concentrations than those of Maryut and Manzalah. In contrast, AVS concentrations were considerably higher in lagoons Manzalah and Maryut and seemed to be consistent with the increase in organic matter than lagoon Burullus. Generally, the average concentrations of the SEM in all lagoons were in the order of Zn > Cu > Ni > Pb > Cd. The ratios of ∑SEM/AVS were less than 1 at all the sampling stations except at one station in lagoon Maryut as well as four stations located in lagoon Burullus (∑SEM/AVS > 1), which suggests that the metals have toxicity potential in these sediments. Therefore, SEM concentrations probably are better indicators of the metal bioavailability in sediments than the conventional total metal concentrations.
在水生沉积物的风险评估中，酸可挥发性硫化物（AVS）对痕量金属的固定作用是控制金属生物有效性及其对水生生物群毒性的主要因素，它通过将金属结合并固定为不溶性硫化物来降低金属的生物有效性和毒性。首次对埃及北部三角洲泻湖（曼扎拉赫、布吕卢斯和马里乌特） 43 个地点的表层沉积物（0-20 厘米）中的 AVS、同时提取的金属（SEM）和沉积物特征进行了空间变异模式研究，作为沉积物中某些二价金属（Cu、Zn、Cd、Pb 和 Ni）生物有效性的预测因子，以及厌氧沉积物中金属毒性的指示剂。结果表明，泻湖布吕卢斯沉积物中的∑SEM（Cu+Zn+Cd+Pb+Ni）值高于马里乌特和曼扎拉赫泻湖。相比之下，AVS 浓度在曼扎拉赫和马里乌特泻湖中要高得多，似乎与有机质的增加一致，而与布吕卢斯泻湖相反。一般来说，所有泻湖的 SEM 平均浓度顺序为 Zn>Cu>Ni>Pb>Cd。除了马里乌特泻湖的一个站点以及布吕卢斯泻湖的四个站点（∑SEM/AVS>1）外，所有采样点的∑SEM/AVS 比值均小于 1，这表明这些沉积物中的金属具有毒性潜力。因此，与传统的总金属浓度相比，SEM 浓度可能是更好的沉积物中金属生物有效性的指示剂。
