基于渗透泵的时间序列采样器的研制及其在河流污染物通量研究中的应用

The time-series dada provide a foundation for the researches to study the spatial and temporal distribution, flux, transport, transformation, and environmental risk assessment of pollutants in aquatic environment. The present passive sampler cannot be used to obtain time-series dada, and the performance of the active sampler based on osmotic pump, which can get time-series dada, is poor. In this study, the osmotic pump and hollow fiber-liquid phase microextraction are combined and the hollow fiber is replaced with unique Teflon® AF tube to develop a new passive sampler that is capable of obtaining time-series dada of trace organic pollutants in aquatic environment. The osmotic pump continuously delivers the extraction solvent stored in a solvent coil into the Teflon® AF tube, where the target pollutants are extracted by the solvent. At the same time, it introduces the extraction solvent with extracted target pollutants into a receiving coil for storage. By renewing the extraction solvent in the Teflon® AF tube, the target pollutants can be sampled continuously. In addition, the active sampler based on osmotic pump is modified to promote its performance. To test the performance, the proposed two time-series samplers will be deployed in Jiulong River, Fujian province, to collect organic pollutants (organphosphorous pesticides and amide herbicides) and heavy metal in the river water. The obtained time-series dada is used to accurately calculate the pollutant flux. The proposed two samplers are free of external power supply with high sampling rate and less biofouling, and thus suitable for long term in situ environmental monitoring. It could be a powerful tool for obtaining time-series dada of pollutants in aquatic environment.

水环境污染物的时间序列监测数据是其时空分布、通量、迁移转化研究和环境风险评价的基础。现有的被动采样器无法实现时间序列采样，可进行时间序列采样的基于渗透泵的主动采样器性能不佳。本课题拟将渗透泵和中空纤维-液相微萃取（HF-LPME）相结合，并用性能优异的Teflon® AF毛细管取代中空纤维，以渗透泵为动力，连续不断地更新Teflon® AF毛细管中的萃取溶剂，研制适于野外应用的时间序列被动采样器，用于获取水环境痕量有机污染的时间序列监测数据；同时改进现有的基于渗透泵的时间序列主动采样器，提高其性能，使之实用化。将两种采样器分别用于福建九龙江河水中有机污染物（有机磷农药和酰胺类除草剂）和重金属的采样，验证其性能，获取时间序列监测数据，进而精确计算污染物通量。研制的两种时间序列采样器无需外部电力供应，采样频率高，受生物污损影响小，适用于长时间的野外原位采样，可望成为水环境污染物监测的有力工具。

水环境污染物的时间序列监测数据是其时空分布、通量、迁移转化研究和环境风险评价的基础，然而采用现有各种采样器进行时间序列采样时存在不少问题。本项目首次利用 RO 膜和离子交换树脂研制出流速稳定、结构简单的渗透泵（Osmotic Pump, OP）；首次将OP与基于Teflon® AF毛细管的液相微萃取（liquid phase microextraction, LPME）技术结合，研制成功无需外界供电的OP-LPME时间序列被动采样器，实现水体中PAHs的时间序列采样监测；将OP与气泡间隔技术结合，研制成功无需外界供电的OP-气泡间隔时间序列主动采样器，实现水体中重金属和营养盐的时间序列采样监测。此外，利用所研制的OP改进OP-SPE（solid phase extraction）时间平均浓度采样器，使其可以准确获取水体中有机污染物的时间平均浓度。经过实验室和野外测试后，将OP-气泡间隔采样器和OP-SPE采样器长时间地布放在福建九龙江上游的平和锦溪中，获取河水中的重金属、营养盐和农药的时间序列数据。. 野外的测试与应用结果显示，所研制的OP无需供电可以在不同的环境中稳定可靠地工作；OP-LPME时间序列被动采样器可以在河流中稳定工作15天，获取水中PAHs的时间序列浓度；OP-气泡间隔采样器可以在河流中稳定工作20天，获取水中重金属和营养盐的时间序列浓度；在平和锦溪的应用中，成功地获得了长达9个月的6种重金属（Mn、Co、Cd、Ni、Cu和Cr）、4种营养盐（溶解态总氮、溶解态总磷、硝酸盐、活性磷）的时间序列浓度（每天1个数据）以及5种农药（chlorpyriphos，pyrimethanil，carbofuran，fenobucarb，buprofezin）的时间平均浓度（每20天1个数据）。这些研究结果证明，所研制的采样器可以成为水环境监测中的有力工具。