九龙江河口水体粪类有机质污染时空变化特征研究

河口是陆源污染物入海的主要通道，在全球气候快速变化和人类活动加剧的背景下，河流入海污染物通量急剧增加，导致河口、海湾及其周边海域水体污染、生态受损等严峻的环境问题发生。本文选取了受极端事件和人类活动影响显著的我国东南强潮型的九龙江河口，利用粪甾醇有机标志物手段开展河口环境粪类污染示踪研究，探讨九龙江河口区粪类污染物（“源”）进入河流后的入海行为（“到”），揭示粪类有机质在近河口海域时空分布特征及受控因素（“汇”）。研究发现，不同季节的河口径流过程和潮汐作用影响粪类有机污染物的时空分布，潮汐过程对中上游河口区水体环境中粪甾醇的赋存影响较大，呈现高潮低浓度而低潮高浓度的潮周期变化特征；河口区粪甾醇在陆−海输运过程的赋存特征还受控于最大浑浊带复杂的水体和沉积动力过程，对粪类有机污染物有一定的净化作用；研究还通过对比人为源贡献主导的氨氮等河流输入的营养盐说明粪甾醇在河口区的时空分布特征与人类活动密切相关。

Decipher temporal and spatial variation characteristics of fecal organic matter pollution by the coprostanol in the Jiulong River Estuary

Estuaries are the main channels for land-derived pollutants to enter the sea. Under the background of rapid global climate change and intensified human activities, the flux of river pollutants into the sea has increased sharply, resulting in serious ecological problems such as water pollution and ecological damage in estuaries, bays and their adjacent marginal seas. This paper selects the Jiulong River Estuary, which is significantly affected by strong tides, extreme events and human activities, and applied a biomarker tool−coprostanol to trace the environmental fecal pollution, explore the enter the sea behavior (“to”) of fecal pollutants (“source”) in the Jiulong River Estuary after entering the river, and reveal the spatial and temporal distribution characteristics and controlled factors (“sink”) of fecal organic matter within the estuary. The study found that the estuarine runoff process and tidal action in different seasons affect the spatial and temporal distribution of fecal organic pollutants, and the tidal process has a greater impact on the occurrence of coprostanol in the water environment of the middle and upper reaches of the estuary, showing a tidal cycle of low concentration at high tide and high concentration at low tide. The occurrence characteristics of coprostanol in the land-sea transport process in the estuarine area are also controlled by the complex water body and sediment dynamic process in the maximum turbidity zone, which has a certain purification effect on fecal organic pollutants. The study also shows that the spatiotemporal distribution characteristics of coprostanol in estuarine areas are closely related to human activities by comparing the nutrient inputs from rivers such as ammonia and nitrogen dominated by anthropogenic contributions.