Concentrations and deposition fluxes of polynuclear aromatic hydrocarbons and heavy metals in the dated sediments of a rural english lake
Concentrations and deposition fluxes of polynuclear aromatic hydrocarbons and heavy metals in the dated sediments of a rural english lake
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英国乡村湖泊定年沉积物中多核芳烃和重金属的浓度和沉积通量
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
H. Dörr
中科院分区：
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作者：
G. Sanders;K. Jones;J. Hamilton;H. Dörr
沉积通量是根据英国乡村湖泊 Ethwaite Water 沉积物岩芯中测量的 12 种多环芳烃 (PAH) 和 6 种重金属的浓度估算得出的。大气沉降是湖泊中多环芳烃和重金属（镉、铜、铅和锌）的主要来源，因此核心的趋势可能表明这些污染物的大气负荷变化的长期记录。自大约 1820 年以来，对岩心进行了放射性测年，并研究了污染物趋势。PAH 通量在世纪之交从稳定的背景水平开始增加（每克干重 4.1 μg ΣPAH，每年每平方厘米 287 ng ΣPAH），在 1950 年至 1970 年间上升至最大输入量（42.0 μg/g，每年 2,954 ng/cm2）。此后，PAH 的沉积通量稳步下降，目前还不到最大值的一半（18.0 μg/g，每年 1,238 ng/cm2）。在最近的沉积物中(1900-1970)，构成ΣPAH负荷的各个PAH的相对比例几乎保持不变，其中荧蒽、芘和苯并苝是最丰富的化合物。然而，二萘嵌苯（一种生物产生的 PAH）在 1890 年以前的沉积物混合物中占主导地位。Esthwaite 沉积物中的镉、铜、镍、铅和锌浓度大致遵循与 PAH 相同的时间趋势，峰值输入在 1925 年至 1975 年间有所不同。现代（地表）沉积物中的浓度现在低于近几十年来，ΣPAH、Cd 和 Pb 显示最大程度的减少。然而，这些污染物到表面沉积物的通量仍然大于 1840 年之前沉积的污染物。
Deposition fluxes have been estimated from concentrations of 12 polynuclear aromatic hydrocarbons (PAHs) and six heavy metals measured in sediment cores from Esthwaite Water, a rural English lake. Atmospheric deposition is a major source of PAHs and heavy metals (Cd, Cu, Pb, and Zn) to the lake, so trends in the core may indicate the long-term record of changes in the atmospheric loading of these pollutants. The cores were dated radiometrically and pollutant trends studied since about 1820. PAH fluxes began to increase from stable background levels around the turn of the century (4.1 μg ΣPAH per gram dry weight, 287 ng ΣPAH per centimeter squared per year), rising to maximum inputs between 1950 and 1970 (42.0 μg/g, 2,954 ng/cm2 per year). The deposition flux of PAHs has decreased steadily since then and is now less than half the maximum (18.0 μg/g, 1,238 ng/cm2 per year). In recent sediments (1900-1970), the relative proportions of individual PAHs making up the ΣPAH burden have remained virtually unchanged, with fluoranthene, pyrene, and benzo[ghi]perylene the most abundant compounds. However, perylene, a biogenically produced PAH, dominates the mixture in the sediments older than 1890. Cadmium, Cu, Ni, Pb, and Zn concentrations in the Esthwaite sediments broadly follow the same temporal trends as the PAHs, with varying peak inputs between 1925 and 1975. Concentrations in the modern (surface) sediments are now lower than in recent decades, with ΣPAH, Cd, and Pb showing the greatest reduction. However, fluxes of these contaminants to surface sediments are still greater than those deposited before 1840.