The application of Diffusive Gradients in Thin Films (DGT) for improved understanding of metal behaviour at marine disposal sites.
The application of Diffusive Gradients in Thin Films (DGT) for improved understanding of metal behaviour at marine disposal sites.
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DOI：
10.1016/j.scitotenv.2016.09.183
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Ruth Parker;T. Bolam;J. Barry;C. Mason;S. Kröger;L. Warford;B. Silburn;D. Sivyer;S. Birchenough;A. Mayes;G. Fones
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文献类型：
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作者：
Ruth Parker;T. Bolam;J. Barry;C. Mason;S. Kröger;L. Warford;B. Silburn;D. Sivyer;S. Birchenough;A. Mayes;G. Fones
评价沉积物金属污染对生物组合和功能的影响仍然是海洋管理中的一个关键问题，特别是在处置活动方面。然而，对孔隙水中生物可利用金属浓度的适当描述很少有报道。在这里，使用薄膜扩散梯度（DGT）研究了英国水域内受污染疏浚材料处置场地的金属行为和可用性。三个站，代表历史对比和疏浚处置的存在进行了研究。利用DGT探针和切片岩心中总金属浓度的离散分析，得到了五种金属的深度剖面。分析的金属有：铁和锰，两者都与沉积物生物地球化学有关；镉、镍和铅被列为优先污染物。DGT时间积分的金属不稳定通量剖面所显示的行为与深度和DGT可用性（铁和锰）、地下峰值和与处置活动（铅和镍）有关的水柱的潜在沉积源（铅和镍）以及与富集植物碎屑分解（镉）有关的向孔隙水的释放相一致。DGT数据有可能提高我们目前对受影响地点金属行为的理解，并且适合作为监测工具。DGT数据可以提供高深度分辨率（5毫米级）沉积物中金属可用性和通量的信息。在DGT和常规总金属分析的结果剖面中观察到的差异说明了同时考虑总金属和潜在不稳定组分的重要性。研究结果可为日后的弃置地点影响评估提供资讯及改善，并可辅以沉积物剖面影像等技术，以改善弃置地点的生物学相关性、空间覆盖范围及具成本效益的监测及抽样。此外，这项技术的应用可以帮助改进在国家和国际主持下关于生物影响的相关工作，将生物效应与更多与生物有关的金属浓度联系起来。
Assessment of the effects of sediment metal contamination on biological assemblages and function remains a key question in marine management, especially in relation to disposal activities. However, the appropriate description of bioavailable metal concentrations within pore-waters has rarely been reported. Here, metal behaviour and availability at contaminated dredged material disposal sites within UK waters were investigated using Diffusive Gradient in Thin films (DGT). Three stations, representing contrasting history and presence of dredge disposal were studied. Depth profiles of five metals were derived using DGT probes as well as discrete analysis of total metal concentrations from sliced cores. The metals analysed were: iron and manganese, both relevant to sediment biogeochemistry; cadmium, nickel and lead, classified as priority pollutants. DGT time-integrated labile flux profiles of the metals display behaviour consistent with increasingly reduced conditions at depth and availability to DGT (iron and manganese), subsurface peaks and a potential sedimentary source to the water column related to the disposal activity (lead and nickel) and release to pore-water linked to decomposition of enriched phytodetritus (cadmium). DGT data has the potential to improve our current understanding of metal behaviour at impacted sites and is suitable as a monitoring tool. DGT data can provide information on metal availability and fluxes within the sediment at high depth-resolution (5 mm steps). Differences observed in the resulting profiles between DGT and conventional total metal analysis illustrates the significance of considering both total metals and a potentially labile fraction. The study outcomes can help to inform and improve future disposal site impact assessment, and could be complemented with techniques such as Sediment Profile Imagery for improved biologically relevance, spatial coverage and cost-effective monitoring and sampling of dredge material disposal sites. Additionally, the application of this technology could help improve correlative work on biological impacts under national and international auspices when linking biological effects to more biologically relevant metal concentrations.