Abstract:

To investigate the spatial-temporal differentiation of total organic carbon (TOC) and black carbon (BC) in the sediments of urban water source reservoirs, and their impacts on polybrominated diphenyl ethers (PBDEs), a class of typical persistent organic pollutants (POPs), sediments of the Shanmei Reservoir and its inflowing river in Quanzhou, China were analyzed to realize the contents, total inventories, spatial distributions, hydrological period changes of TOC and BC, the relations between BC and TOC and their influences on the spatial and temporal differentiation of PBDEs. Results showed that the TOC and BC contents were 15.08mg/g±2.70mg/g (10.87—19.61mg/g) and 3.55mg/g±1.14mg/g (2.08—6.92mg/g) respectively, and the total inventories were 107445t and 25294t, which were at the lower-middle levels compared with other lakes and reservoirs at home and abroad. Distinct differences were found in the spatial and temporal differentiation between TOC and BC. TOC was significantly affected by the hydrological period changes (P<0.001), while BC was significantly affected by the spatial distributions (P=0.001). There were no significant correlations between TOC and BC (P≥0.226), indicating that their sources were different. TOC was more susceptible to the influx of inflowing river than BC. The BC/TOC ratios (wet 0.24±0.09, dry 0.21±0.06, normal 0.27±0.08) of each hydrological period in Shanmei Reservoir were between 0.11 and 0.5, indicating that BC was generated by the combined sources of both biomass burning and some fossil fuel combustion. BC in the inflowing river was more affected by biomass burning than the reservoir area. The spatiotemporal differentiation of ΣPBDEs, Deca-BDE and Nona-BDE were significantly affected by TOC, and the spatiotemporal differentiation of the major lower brominated BDE produced by Deca-BDE degradation were also affected somehow by TOC to some extent. The primary pollution source of TOC and PBDEs in each hydrological period was the same, both was the inflowing river, and their spatial distributions were roughly the same. TOC was an important controlling factor for the spatial and temporal differentiation of PBDEs. There were no significant correlations between BC and PBDEs in each hydrological period due to their different sources, but BC could adsorb a large amount of PBDEs released by local pollution sources, which still had a considerable impact on their spatiotemporal differentiation.

Key words: water source reservoir, sediment, total organic carbon, black carbon, spatiotemporal differentiation, polybrominated diphenyl ethers (PBDEs), adsorption, biomass

摘要：

为了解城市水源水库沉积物中总有机碳（TOC）和黑碳（BC）的时空分异及其对典型持久性有机污染物（POPs）——多溴二苯醚（PBDEs）的影响，本文分析了泉州山美水库及入库河流沉积物中TOC和BC的含量、赋存总量、空间分布、水文期变化、BC和TOC的关系及两者对PBDEs时空分异的影响。结果表明：TOC和BC含量分别为15.08mg/g±2.70mg/g（10.87~19.61mg/g）和3.55mg/g±1.14mg/g（2.08~6.92mg/g），赋存总量分别为107445t和25294t，较国内外其他湖库处于中低水平。TOC和BC的时空分异规律存在差异，TOC主要受水文期变化的显著影响（P<0.001），而BC则受空间分布的显著影响（P=0.001）。TOC与BC无显著相关性（P≥0.226），显示两者来源不同，TOC较BC更易受到入库河流输入的影响。山美水库各水文期BC/TOC（丰水0.24±0.09、枯水0.21±0.06、平水0.27±0.08）均介于0.11~0.5，显示其BC为生物质燃烧和部分化石燃料燃烧的复合来源。入库河流BC受生物质燃烧源的影响大于库区。ΣPBDEs、Deca-BDE和Nona-BDE的时空分异受到了TOC的显著影响，且Deca-BDE降解产生的主要低溴BDE的时空分异也受到了TOC不同程度的影响。各水文期TOC和PBDEs的主要污染源相同，均为入库河流，且二者空间分布规律大致相同，TOC是PBDEs时空分异的重要控制因素。各水文期BC与PBDEs因来源不同而均无显著相关性，但BC可大量吸附固定局地污染源释放的PBDEs，对其时空分异仍有重要影响。

关键词: 水源水库, 沉积物, 总有机碳, 黑碳, 时空分异, 多溴二苯醚, 吸附, 生物质