广东红树林保护区典型植被沉积物微塑料赋存特征与分异机制

Microplastic Occurrence Characteristics and Differentiation Mechanisms in Typical Vegetation Sediments of Mangrove Reserves in Guangdong Province

摘要: 研究以粤港澳大湾区典型的福田与淇澳红树林保护区为对象，通过系统采样与分析，探讨了不同植被区沉积物中微塑料的赋存特征、空间分异及其驱动机制。结果显示，两地存在普遍的微塑料污染并且整体丰度相近。但物理化学特征迥异：福田保护区的微塑料以聚乙烯(PE) (19.0%)和聚丙烯(PP)(17.8%)为主，形态主要是颗粒(40.9%)、纤维(29.8%)，说明其污染主要源于高度城市化背景下的包装与日用消费品；淇澳保护区则以聚酰胺(PA)(16.7%)和聚对苯二甲酸乙二醇酯(PET) (16.3%)为主，且纤维形态占据绝对主导(>65%)，这与当地渔业及纺织活动排放密切相关。空间分布上，微塑料丰度遵循“原生红树林 > 排污口 ≈ 入侵红树林 > 无植被滩涂”的规律，证实了红树林植被对微塑料显著的截留效应，且该效应与输入源特征存在交互作用。冗余分析与相关性分析表明，土壤基础理化性质对微塑料分布无显著影响。人类活动强度与微塑料的组成特征(如碎片、PE、PP占比)呈显著正相关，但与其绝对丰度无显著相关性。这表明，微塑料的最终赋存状态是“源特征”(由人类活动类型决定)与“汇过程”(如植被截留、水动力迁移)共同作用的结果。研究揭示了红树林微塑料污染特征的局地分异性，强调污染管控需结合区域主导人类活动类型，并为评估红树林生态系统的“减污”功能提供了科学依据。

Abstract: This study investigated the occurrence characteristics, spatial differentiation, and driving mechanisms of microplastics in sediments from different vegetation zones in the typical Futian and Qi’ao mangrove reserves in the Guangdong-Hong Kong-Macao Greater Bay Area through systematic sampling and analysis. The results showed that microplastic pollution was prevalent in both areas, with similar overall abundance. However, their physicochemical characteristics differ significantly: In the Futian Nature Reserve, microplastics are mainly polyethylene (PE) (19.0%) and polypropylene (PP) (17.8%), primarily in the form of particles (40.9%) and fibers (29.8%), indicating that the pollution mainly originates from packaging and daily consumer goods in a highly urbanized environment. In the Qi’ao Nature Reserve, microplastics are mainly polyamide (PA) (16.7%) and polyethylene terephthalate (PET) (16.3%), with fibers dominating (>65%), closely related to emissions from local fisheries and textile activities. Spatially, microplastic abundance follows the pattern of “native mangroves > sewage outlets ≈ invasive mangroves > unvegetated mudflats,” confirming the significant interception effect of mangrove vegetation on microplastics, and this effect interacts with the characteristics of the input sources. Redundancy and correlation analyses show that the basic physicochemical properties of the soil have no significant impact on microplastic distribution. The intensity of human activities showed a significant positive correlation with the compositional characteristics of microplastics (e.g., the proportion of fragments, PE, and PP), but no significant correlation with their absolute abundance. This indicates that the final state of microplastics is the result of the combined effects of “source characteristics” (determined by the type of human activity) and “sink processes” (e.g., vegetation interception and hydrodynamic migration). This study reveals the local differentiation of microplastic pollution characteristics in mangroves, emphasizing that pollution control needs to be combined with the dominant human activity type in the region, and provides a scientific basis for assessing the “pollution reduction” function of mangrove ecosystems.