Dissolved heavy metal fluxes at sediment-water interface in polluted sediments of the Adriatic Sea

Abstract

<p>To evaluate the anthropogenic impact in surface sediments of the Northern and Central Adriatic Sea, dissolved fluxes at the sediment water interface of heavy metals and nutrients on the sea bottom in front of the Po River mouths and along the western side of the Northern and Central Adriatic Sea have been determined. The fluxes have been measured by benthic chamber deployments and calculated by pore water modelling. Pore waters composition have been used also to understand the early diagenesis processes generating the benthic fluxes.</p><p>Benthic chamber deployments and sediment core collection for pore water extraction have been carried out in three cruises in spring and autumn 2013 and autumn 2014.</p><p>The study stations have been chosen on the base of previous research results indicating a decreasing heavy metal and organic matter surface content leaving from the Po River mouths (Pérez-Albaladejo et al., 2016). The data obtained have been compared with previous studies carried in the Adriatic Sea (Spagnoli et al. 2010).</p><p>Results of the 2013 and 2014 cruises and of previous investigations indicate a consistent and rapid dissolved benthic flux decreasing going away from the Po River mouths both southward, eastward and northward.</p><p>The decreasing regards the final electron acceptors and the organic matter degradation products and some heavy metals.</p><p>On the whole, different early diagenesis environments have been recognized in the Northern and Central Adriatic Sea: they embrace two end members: from the Po River Prodelta to the Mid Adriatic Depression (MAD) (Spagnoli et al., 2014). In front of the Po River sediments are characterized by high sedimentation rate and by high inputs of fresh marine organic matter, continental organic matter and Fe-oxyhydroxides. These inputs produce high concentrations of organic matter degradation products, strong anoxic environment in the pore waters and high dissolved benthic fluxes. In the MAD the diagenetic environments are characterized by low sedimentation rate and low inputs of reactive organic matter that produce low concentrations of pore-water organic matter degradation products with oxic conditions near the surface and weak benthic fluxes.</p><p>As regard the two major metals involved in the early diagenesis processes (Fe and Mn), they too show dissolved benthic fluxes decreases from the Po River mouths. Also in this case, this trend is attributed to the high Po River dissolved and particulate, anthropogenic and natural, metal inputs that deposit in the surface sediments of the Po Prodelta (Spagnoli and Bergamini, 1997).</p><p>The dissolved benthic fluxes of trace heavy metals (Co, Ni, Zn, Cu, Cd, Pb) indicate that some elements, such as Co and Pb, are clearly adsorbed by the sediment that act, for these two elements as sink. Other elements, such as Cu, don’t show a clear north–south trend s, while other elements, such as Cd, indicate a southward decreasing trend suggesting a behavior affected by the Po River inputs and Fe-Mn-oxyhydroxide cycle.</p>

Sources and Metal Pollution of Sediments from a Coastal Area of the Central Western Adriatic Sea (Southern Marche Region, Italy)

“…As regards the Cr, almost all samples exceed the TEL, 11 samples exceed the ERL and 3 samples overcame the PEL. The high contents of Cr that generally exceed the lower levels of some SQGs are ascribed to the composition of the sediments coming from the North that exhibits high Cr levels [14] and are a well-known geochemical signature sediment associated to the Po river in northern areas [83][84][85]. As regard the Ni, 34 stations exceed the TEL, 25 the ERL, and 16 the PEL.…”

“…Anthropogenic chemicals can be introduced into the marine environments by different sources (i.e., effluent treatment plants, accidental discharges, dumping, riverine inputs, surface runoff, 2 of 27 atmospheric deposition, etc.) and then accumulate in sediments [9][10][11][12][13][14][15]. In coastal marine sediment, however, heavy metals might be sourced by anthropic activity or by natural sources [8,16] and could represent a serious hazard due to their toxicity, bioavailability and persistence [17,18].…”

The AMERIGO Lander and the Automatic Benthic Chamber (CBA): Two New Instruments to Measure Benthic Fluxes of Dissolved Chemical Species

“…The Amerigo Lander [63,64,65,66,67,68,69,70,71] and the CBA [41,42,70,71,72,73,74,75,76,77] have successfully been tested and used in measurement and research activities carried out in the framework of international and national projects and in environmental investigations into the impacts of human activities on marine (e.g., harbor sediment dredging) or land environments (e.g., quality of drinking water).…”

“…As a discussion of the data collected by the two devices, we report (Figure 16) the trend of the dissolved oxygen concentrations, measured in the benthic chambers of the lander (by the AANDERAA optode oxygen sensors, Aanderaa Data Instruments AS, Bergen, Norway) and the CBA (by the Hydrolab MS5 oxygen sensor, OTT HydroMet, Kempten, Germany), at the same deployment time and site [71], and on a pelitic and organic matter-rich bottom in front of the Po River Estuary [78,79]. All the benthic chambers of the two devices recorded similar continuously decreasing values, due to mineralization of the high content in fresh reactive organic matter, deposited in front of the Po River Estuary.…”

Selected Papers from the 2018 IEEE International Workshop on Metrology for the Sea

“…Since 2004 several wide coastal monitoring programmes supported by the European Union (POR 2000-2006 and FESR 2007-2013 funds) have been carried out in Apulia region, allowing to obtain a detailed picture of the coastal trends and a huge database for scientific research. Those programmes included many actions: bathymetric, topographic and sedimentologic field campaigns, aerial and LIDAR surveys, real-time shoreline monitoring using webcams [14,16,28,29] and a deployment of a meteomarine network (Apulia Region Meteomarine Network, hereinafter referred to as "SIMOP") [70][71][72]. The availability of marine weather measures turns out to be extremely helpful for accurate selection of SAR acquisitions available in the CSK archive, based on a preliminary check on the sea weather conditions at the acquisition time.…”