桂林市不同功能型公园水体微塑料的分布特征及风险评估

城市公园水体环境容量小，自净能力差，更容易受微塑料影响而造成水体微生态系统的失衡.以公园的功能特点(综合型、社区型和生态型)为基础，通过现场采样、显微观察和傅里叶红外光谱等方法，调查了桂林市公园水体微塑料的分布特征，并采用微塑料风险指数(H)和负荷指数(PLI)评估了微塑料的污染风险.结果表明，公园表层水和沉积物中微塑料的丰度范围分别为104.67～674.44 n·m^-3和95.57～877.78 n·kg^-1.微塑料形状主要包含碎片、纤维、薄膜和颗粒，且以小于1 mm的碎片和纤维为主.微塑料聚合物有聚乙烯和聚对苯二甲酸乙二醇酯.不同功能公园水体的微塑料丰度差异性显著，其中综合型公园的微塑料丰度最高.公园水体微塑料丰度与公园功能和入园人数密切相关.公园表层水的污染风险较低，而沉积物的污染风险相对较高.研究表明，旅游是桂林城市公园水体微塑料污染的重要来源，桂林市公园水体中微塑料污染风险总体属于轻度污染，但仍需关注其在城市小型淡水水域中的累积风险.

Distribution Characteristics and Risk Assessment of Microplastics in Water of Different Functional Parks in Guilin

The water environment capacity of urban parks is small, and their self-purification ability is poor. They are also more likely to be affected by microplastics (MPs), which cause an imbalance of the water micro-ecosystem. Based on the functional characteristics of parks (comprehensive park, community park, and ecological park), this study investigated the distribution characteristics of MPs in the water of Guilin parks through spot sampling, microscopic observation, and Fourier transform infrared spectroscopy. In addition, the pollution risk index and the pollution load index were used to evaluate the pollution risk of MPs.The results showed that the abundances of MPs in the park surface water and sediments ranged from 104.67-674.44 n·m^-3 and 95.57-877.78 n·kg^-1, respectively. There were four main shape types of MPs:fragments, fibers, films, and particles. MPs were dominated by fragments and fibers with small sizes (<1 mm). The polymers of MPs were polyethylene and polyethylene terephthalate. There were significant differences in the abundance of MPs in the water of different functional parks, and the abundance of MPs in comprehensive parks was the highest. The abundance of MPs in park water was closely related to the function of the park and the number of people entering the park. The pollution risk of MPs in the surface water of Guilin parks was low, whereas the pollution risk of MPs in sediments was relatively high. The results of this study indicated that tourism was an important source of MPs pollution in the water of Guilin City parks. The pollution risk of MPs in the water of Guilin City parks was mild. However, the pollution risk of MPs accumulated in small freshwater waters of urban parks requires continued attention.