European Regional Centre for Ecohydrology, Polish Academy of Sciences, Tylna 3, 90-364, Lodz, Poland,
Environ Sci Pollut Res Int. 2014 Mar;21(6):4441-52. doi: 10.1007/s11356-013-2401-7. Epub 2013 Dec 12.
Reservoirs situated along a river continuum are ecosystems where rates of transfer of suspended matter and associated micropollutants are reduced due to sedimentation, accumulation, and biological and physical transformation processes. Among the micropollutants, PCDDs and PCDFs are substances that are highly toxic and carcinogenic for humans and animals. They are emitted and dispersed in the environment throughout the whole catchment area and may accumulate in aquatic and terrestrial food chains, creating a risk for human health. A wealth of data exists indicating the increase in the concentrations of pollutants along a river continuum. A comparative analysis of total, individual, and TEQ PCDD/PCDF concentrations in large lowland, shallow reservoirs located in different catchments ("I"-industrial/urban/agricultural, "U"-urban/agricultural, and "A"-agricultural/rural) showed decreases of the TEQ concentrations in bottom sediments along a gradient from the middle sections to the dam walls. Moreover, penta-, hexa-, and heptachlorinated CDD/CDF congeners were reduced from 28.8 up to 93.6 % in all three types of reservoirs. A further analysis of water samples from the inlets and outlets of the "A" reservoir confirmed this tendency.
由于沉降、积累以及生物和物理转化过程，悬浮物质和相关的微量污染物的转移率降低。在这些微量污染物中，多氯二苯并对二恶英（PCDDs）和多氯二苯并呋喃（PCDFs）对人类和动物具有高度毒性和致癌性。它们在整个集水区内排放和分散到环境中，并可能在水生和陆地食物链中积累，对人类健康造成威胁。有大量数据表明，沿河流连续体的污染物浓度在增加。对位于不同流域的大型低地浅水库中的总、单个和等效毒性多氯二苯并对二恶英/多氯二苯并呋喃（PCDD/PCDF）浓度进行的对比分析表明，随着从中段到坝壁的梯度增加，底泥中的等效毒性浓度降低。此外，在所有三种类型的水库中，五氯、六氯和七氯代二苯并对二恶英/二苯并呋喃同系物的浓度从 28.8%减少到 93.6%。对“A”水库进出口处的水样进行的进一步分析证实了这一趋势。
