Coastal and estuarine sediment archives for flood-induced pollution in subtropic / tropic areas – a proof-of-concept study

对申请人进行的初步概念验证研究侧重于影响钦奈（印度泰米尔纳德邦）市区的Adyar河和Cooum河两个河流系统的河岸湿地。相应的结果指出了三个值得注意的方面：(i)金奈城市河流洪泛平原并不代表河流沉积物污染的重要沉积系统；（ii）即使浓度在中低水平，也可检测到广泛的污染物；（ii）特别是有机污染物，已确定了几种来源特定的指示性化合物。但是，主要的堆积沉积物，特别是城市垃圾排放，能否作为反映污染历史的沉积档案，仍然是一个问题。因此，本项目拟对同一水系的河口水系和回水水系作为合适的主要泥沙堆积区进行试验。第一个目标是确定适当的沉积物档案，反映洪水/季风驱动的污染物在印度河流系统向沿海系统的冲刷。在这里，城市河流系统与河口和回水地区的相互作用是重点。其次，利用特定的标记物质和元素，建立首份污染史，反映沿河道特别是城区排放的各种排放源。将对河口和相连海岸线上的三个不同区域进行取样和测试，以确定它们作为河流排放的长期沉积沉积物的潜力。这包括直接在河口的河口地区（洪泛平原和河岛），近岸地区以及在Pulicat泻湖和Muttukadu的回水系统，通过白金汉运河与河流系统相连。最后，对河口、回水和海岸岩心样品的地球化学比较将测试作为沉积档案的能力，并将揭示Adyar和Cooum衍生颗粒物再沉积和聚集过程的证据。通过对选定沉积物岩心中的指示物质和元素的定量分析，将以金奈的城市排放为重点，举例重建河流污染历史。

A precursory proof-of-concept study of the applicants focused on riparian wetlands of two river systems, the Adyar and Cooum rivers, affecting the urban area of Chennai (Tamil Nadu, India). The corresponding results pointed to three remarkable aspects: (i) The urban riverine floodplains in Chennai do not represent significant deposition systems for the riverine sediment-bound pollution; (ii) a broad spectrum of pollutants was detectable even though on a moderate to low concentration level and (ii) in particular for the organic contaminants, several source specific and, therefore, indicative compounds have been identified. However, the question on the major accumulation deposit for the especially urban waste emissions, that can act as sedimentary archive reflecting the pollution history, still remains.Therefore, this project consecutive proposal is intended to test estuarine and backwater systems of the same river systems as suitable major sediment accumulation areas. A first aim is the identification of appropriate sediment archives reflecting the flood/monsoon-driven flushing-out of pollutants at the Indian river systems towards the coastal systems. Here, the interaction of urban riverine systems with the estuarine and backwater areas is focused on. Secondly, a first pollution history using specific marker substances and elements reflecting the various emission sources discharging along the river’s course and in particular the urban area will be built up.Three different areas at the estuary and along the connected coastline will be sampled and tested for their potential to act as sedimentary long-term deposits of riverine discharge. These includes the estuarine area directly at the river mouths (floodplains and river islands), the nearshore areas as well as the backwater systems at Pulicat lagoon and Muttukadu connected to the river systems by the Buckingham canal.Finally, the geochemical comparison of estuarine, backwater and coastal core samples will test the ability to act as sedimentary archives and will reveal evidence for redeposition and accumulation processes of Adyar and Cooum derived particulate matter. The riverine pollution history with particular focus on the urban emissions of Chennai will be exemplarily reconstructed by quantitative analyses of indicator substances and elements in selected sediment cores.