封闭海湾沉积物的污染状态直接关联到海岸环境生态安全。杏林湾作为人工封闭海湾，在实施环湾截污等措施后，水质仍存在不稳定达标风险，这极可能危及区域城市经济与社会发展。基于此，本文对湾区沉积物样品的污染状态进行分析和指数评价，并由此提出相应的治理对策。分析主要结果表明，湾区表层沉积物有机质含量为1.93~15.40%，TN(total nitrogen)含量为650~3980 mg·kg-1，TP(total phosphorus)含量为311~2470 mg·kg-1，三者均呈现北侧入湾河口和环湾东西两侧区域高，中部和近海堤处低的相似规律。表层沉积物有机指数为0.07~2.53，中度和重度污染点位占比54.3%，主要分布在北侧入湾河口、环湾区域；表层沉积物TP单因子指数为0.52~4.12，中度和重度污染点位占比30%，分布特征与前者类似。沉积物污染垂向分布特征表现为含量随采样深度增加逐渐降低，环湾东西两侧及北部入湾口区域表层污染富集现象明显。针对沉积物污染空间分布特征及评价结果，重点提出环保清淤与原位生态基底修复相结合的内源头污染分区分质治理方法，可为杏林湾湾区水环境综合治理提供重要技术支持。
Sediment pollution in closed bays is directly impacts the ecological security of coastal environments. As a closed bay, Xinglin bay faces ongoing challenges in achieving stable water quality standards, even after the implementation of pollution control measures. This instability poses a risks to the regional urban economy and social development. In response, we analyzed and evaluated sediment samples from the bay, proposing appropriate control measures. The analysis results indicate that the organic matter content of surface sediments ranged from 1.93% to 15.40%, total nitrogen(TN) from 650 to 3980 mg·kg-1, and total phosphorus(TP) from 311 to 2470 mg·kg-1. These pollutants exhibited higher concentrations in the eastern and western bay rims and the northern inlet estuary, while lower levels were observed in the center and near the seawall. The organic index of the surface sediments ranged 0.07 to 2.53, with 54.3% of the sites showing moderate to severe pollution levels, predominantly near the northern inlet estuary, bay rims; the TP single factor index of surface sediments ranged from 0.52 to 4.12, with 30% of sites showing moderate to severe pollution levels, and the distribution characteristics were similar to those of the former. The vertical distribution analysis showed that the content gradually decreased with depth, with significant enrichment in surface layers, particularly in the eastern and western bay rim and the northern inlet estuary areas. Based on the spatial distribution characteristics and pollution evaluation results, a combination of conventional dredging and in-situ ecological restoration was proposed to provide crucial support for the comprehensive water environment improvement in the Xinglin Bay Area.
