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Abstract：
To obtain the historical changes of pyrogenic sources, integrated source apportionment methods, which include PAH compositions, diagnostic ratios (DRs), Pb isotopic ratios, and positive matrix factorization (PMF) model, were developed and applied in sediments of the northern South China Sea. These methods provided a gradually clear picture of energy structural change. Spatially, Σ15PAH (11.3 to 95.5ng/g) and Pb (10.2 to 74.6μg/g) generally exhibited decreasing concentration gradient offshore; while the highest levels of PAHs and Pb were observed near the southern Taiwan Strait, which may be induced by accumulation of different fluvial input. Historical records of pollutants followed closely with the economic development of China, with fast growth of Σ15PAH and Pb occurring since the 1980s and 1990s, respectively. The phasing-out of leaded gasoline in China was captured with a sharp decrease of Pb after the mid-1990s. PAHs and Pb correlated well with TOC and clay content for core sediments, which was not observed for surface sediments. There was an up-core increase of high molecular PAH proportions. Coal and biomass burning were then qualitatively identified as the major sources of PAHs with DRs. Furthermore, shift toward less radiogenic signatures of Pb isotopic ratios after 1900 revealed the start and growing importance of industrial sources. Finally, a greater separation and quantification of various input was achieved by a three-factor PMF model, which made it clear that biomass burning, coal combustion, and vehicle emissions accounted for 40±20%, 41±13%, and 19±12% of PAHs through the core. Biomass and coal combustion acted as major sources before 2000, while contributions from vehicle emission soared thereafter. The integrated multi-methodologies here improved the source apportionment by reducing biases with a step-down and cross-validation perspective, which could be similarly applied to other aquatic systems.
摘要：
为了获得火源的历史变化，集成源分配方法，其中包括PAH成分，诊断比率(DR)，Pb同位素比，和正矩阵分解(PMF)模型，被开发并应用于南海北部的沉积物。这些方法提供了能量结构变化的逐渐清晰的画面。空间上,Σ15PAH（11.3至95.5ng/g）和Pb（10.2至74.6μg/g）通常在近海表现出降低的浓度梯度；而台湾海峡南部附近的PAHs和Pb含量最高，这可能是由不同河流输入的积累引起的。污染物的历史记录紧随中国经济的发展,随着20世纪80年代和90年代Σ15PAH和Pb的快速增长，分别。1990年代中期以后，随着铅的急剧下降，中国逐步淘汰了含铅汽油。PAHs和Pb与岩心沉积物的TOC和粘土含量密切相关，没有观察到表面沉积物。高分子量PAH比例增加。然后定性地将煤和生物质燃烧确定为具有DRs的PAHs的主要来源。此外，1900年后，铅同位素比的放射性特征向较低的方向转变，揭示了工业来源的开始和日益重要。最后,通过三因素PMF模型实现了各种输入的更大分离和量化，这清楚地表明生物质燃烧，煤燃烧，车辆排放占40±20%，41±13%,和19±12%的PAHs通过核心。在2000年之前，生物质和煤炭燃烧是主要来源，而此后车辆排放的贡献猛增。这里集成的多方法通过逐步降低和交叉验证的角度来减少偏差，从而改善了源分配，可以类似地应用于其他水生系统。
