School of Geography and Planning, Sun Yat-Sen University, Guangzhou, 510275, China.
School of Geography and Planning, Sun Yat-Sen University, Guangzhou, 510275, China.
Environ Pollut. 2017 May;224:70-81. doi: 10.1016/j.envpol.2016.12.056. Epub 2017 Mar 9.
Reconstructing historical sedimentary records is essential for better understanding the effects of anthropogenic activities on river environments. We used lead-210 to date riverine sediment core from the Shima River in China. We obtained a sedimentary history of 34 years (1982-2015) for core S2, which had a length of 34 cm. The sedimentation rate of 0.304-2.04 cm y was controlled by both flood events and anthropogenic activities. The conservative element content depth profiles remained relatively constant, suggestive of a relatively stable sediment provenance; therefore, the increase in the sedimentation rate over time was mainly the result of domestic and industrial wastewater effluent and the construction of a rubber dam at the middle and lower reach of the Shima River. From 1982 to 2015, the nutrient and trace metal depth profiles could be divided in three periods based on their trends. From 1982 to 1993, the vertical profiles of nutrients (organic carbon, total phosphorus, and total nitrogen) and three trace metals (nickel, zinc, and manganese) were relatively stable; however, the gradual decrease in copper and cadmium was likely associated with a reduction in agricultural chemical application. From 1993 to 2003, a population explosion and rapid industrialization were responsible for an increase in the input of pollutants into the Shima River, which was partly attenuated by water from the Dong River, leading to a gradual increase in nutrient and trace metal contents. Finally, from 2003 to 2015, the Shima River stopped being used as a source of water due to its deteriorating water quality. The relatively lower velocity of the water flow after the recovery of its flow direction and the reconstruction of the rubber dam in 2009 provided advantageous sedimentary conditions, promoting nutrient accumulation and significant trace metal enrichment.
重建历史沉积记录对于更好地理解人为活动对河流环境的影响至关重要。我们使用铅-210 对中国仕马河流域的河流沉积物芯进行定年。我们获得了 S2 芯 34 年（1982-2015 年）的沉积历史，芯长 34 厘米。0.304-2.04cm·y-1 的沉积速率受洪水事件和人为活动的控制。保守元素含量的深度剖面相对稳定，表明沉积物物源相对稳定；因此，随着时间的推移，沉积速率的增加主要是由于生活污水和工业废水以及仕马河中下游橡胶坝的建设造成的。1982 年至 2015 年，根据趋势可将营养物质和痕量金属深度剖面分为三个时期。1982 年至 1993 年，营养物质（有机碳、总磷和总氮）和三种痕量金属（镍、锌和锰）的垂直剖面相对稳定；然而，铜和镉的逐渐减少可能与农业化学品施用量的减少有关。1993 年至 2003 年，人口爆炸和快速工业化导致污染物输入仕马河的增加，部分被东河来水所衰减，导致营养物质和痕量金属含量逐渐增加。最后，2003 年至 2015 年，由于水质恶化，仕马河不再作为水源。水流方向恢复和 2009 年橡胶坝重建后，水流速度相对较低，为养分积累和显著的痕量金属富化提供了有利的沉积条件。
