珠江口及近岸南海哺乳动物中氯化石蜡的生物累积特征、污染源解析和大气输送影响

Chlorinated paraffins (CPs) are one complex group of persistent halogenated compounds (PHCs) which have been found to be ubiquitous in the Chinese environment in recent years. As a new candidate of persistent organic pollutants (POPs), CPs are under the evaluation for inclusion into the Stockholm Convention on POPs. Environment pollution caused by CPs is relatively serious in China, but to date, studies on the analytical methods and environmental behaviors are still limited. As major sinks for many organic contaminants emitted from the Pearl River Delta (PRD), Pearl River Estuary (PRE) and the adjacent coast of the South China Sea (SCS) are facing serious chemical pollution, where various emerging contaminates show increasing pollution levels in recent years. Our preliminary experimental results have indicated that the elevated concentrations of CPs can be detected in two types of marine mammals from the PRE and SCS, respectively. In this project, we will devote to develop and optimize the environmental analytical methods for simultaneously measuring short- and middle-chain chlorinated paraffins with high accuracy and sensitivity, and reveal their pollution status in the PRE and SCS coast. Furthermore, we aim to study the bioaccumulation and temporal trends in marine mammals, to examine the tropic transfer, biotransformation and biomagnification in marine food webs, and to track dietary sources and the contribution from atmospheric transportation. The results of this project are expected to further reveal the environmental behaviors and transportation mechanism of CPs in the representative marine ecosystem, and also to provide scientific data and technical support for health risk assessment and control strategy.

氯化石蜡是近年来我国环境中发现的一类无所不在的复杂的持久性有机卤代污染物，同时也是《斯德哥尔摩公约》重点审查和评估的一类新型化合物。当前我国氯化石蜡污染形势严峻，但对氯化石蜡的分析方法和环境行为研究仍非常有限。作为珠江三角洲环境污染物的一个重要的“汇”，珠江口及近岸南海正面临着严重的化学污染，近年来各种污染物的含量都明显增加。我们的初步研究表明，该区域海洋哺乳动物中存在较为严重的氯化石蜡污染。本项目拟针对该特定区域，发展和优化氯化石蜡环境分析方法学，揭示珠江口及近岸南海典型海岸生态系统中氯化石蜡的污染现状，深入系统地研究氯化石蜡在海洋食物链顶端哺乳动物中的生物蓄积特征和时间演变趋势，追踪氯化石蜡在食物链上的传递转化和富集放大规律，解析污染来源和大气输送影响。研究结果将进一步阐明氯化石蜡的区域环境化学行为和传输机制，为健康风险评估和国家履约谈判提供科学数据和技术支持。

短链氯化石蜡是环境中最复杂的一类新型持久性有机污染物。作为珠江三角洲环境污染物的一个重要的“汇”，珠江口及近岸南海正面临着严重的化学污染。本项目以氯化石蜡为研究对象，围绕珠江口及近岸南海哺乳动物中氯化石蜡的生物累积特征、污染源解析和大气输送影响展开研究和探讨，获得了如下重要结果：I) 揭示了珠江口和近岸南海两类海洋哺乳动物（中华白海豚和江豚）中短链和中链氯化石蜡高的生物蓄积，其浓度在近十年呈现逐年累增的时间变化趋势。发现短链和中链氯化石蜡在海洋食物链上的生物放大效应。阐明了食物暴露是海洋哺乳动物中氯化石蜡蓄积的主要来源。II) 揭示了珠江三角洲和河流沉积物中存在严重的氯化石蜡污染，其污染水平与区域工业化程度密切相关，同样发现我国近岸南海海域沉积芯中短链和中链氯化石蜡浓度均呈现逐年上升的时间变化趋势。III) 发现电子垃圾拆解过程中氯化石蜡可能大量地释放到周围环境，并可能通过大气和雨水冲刷汇聚到我国珠江口和近岸南海海域。IV) 发现氯化石蜡在大气颗粒物中存在明显的粒径分布特征，揭示了同族体的蒸气压是控制粒径分布的决定性因子。上述重要结果和研究数据对于认识氯化石蜡在环境中的迁移、生物积累和生态风险具有重要意义。