Institute of Ocean Sciences, Fisheries and Oceans Canada, 9860 W. Saanich Rd., P.O. Box 6000, Sidney, B.C., Canada.
Mar Pollut Bull. 2012 Apr;64(4):675-8. doi: 10.1016/j.marpolbul.2012.01.026. Epub 2012 Feb 13.
Marine sediment preserves a useful archive for contaminants and other properties that associate with particles. However, biomixing of sediments can smear the record on a scale of years to thousands of years, depending on sedimentation rate and on the depth and vigour of mixing within a particular sediment. Where such mixing occurs, dates can no longer be associated with discrete sediment depths. Nevertheless, much can still be learned from biomixed profiles, provided that mixing is accounted for. With no modelling at all, it is possible to calculate an inventory of a contaminant at a site and a maximum possible sedimentation rate, and to determine whether the contaminant has increased or decreased over time. Radiodating the core with (210)Pb permits the estimation of sedimentation and mixing rates, which can be combined with the surface contaminant concentration to estimate an approximate flux of the contaminant. Numerical models that incorporate sedimentation and mixing rates (determined using (210)Pb and other transient signals with known deposition histories) can provide the basis to propose plausible histories for contaminant fluxes.
海洋沉积物是污染物和其他与颗粒相关的特性的有用档案。然而，沉积物的生物混合会在数年至数千年的时间内抹去记录，具体取决于沉降速度以及特定沉积物中混合的深度和强度。在发生这种混合的地方，日期不再与离散的沉积物深度相关。尽管如此，如果考虑到混合，仍然可以从生物混合剖面中获得很多信息。如果根本没有建模，则可以计算出一个地点的污染物清单和最大可能的沉降速率，并确定污染物是否随时间增加或减少。用（210）Pb 对岩芯进行放射性测年，可以估算沉降和混合速率，然后将其与表面污染物浓度相结合，估算污染物的通量。包含沉降和混合速率的数值模型（使用（210）Pb 和其他具有已知沉积历史的瞬态信号确定）可以为提出污染物通量的合理历史提供依据。
