Evaluation of Discrete and Passive Sampling (Diffusive Gradients in Thin-films – DGT) Approach for the Assessment of Trace Metal Dynamics in Marine Waters – a Case Study in a Small Harbor

Abstract

Two complementary approaches, based on discrete and passive samplings (diffusive gradients in thin-films -DGT), supported by the speciation modeling, were evaluated for the assessment of distribution and operational speciation of trace metals (Zn, Cd, Pb, Cu, Ni and Co) within a small marine harbor (Rijeka, Croatia). Concentrations of dissolved metals were relatively low and comparable to, or slightly above those found in coastal Adriatic region. Compared to higher variability of dissolved metal concentrations due to the discrete sampling, smoother temporal distribution was recorded for DGT-labile metals. The percentages of DGT-labile metal concentrations, which reflect their affinity to organic matter, varied among metals with the following order: Cu < Zn ≈ Co < Ni < Cd ≈ Pb. DGT-labile metal concentrations predicted by speciation modeling were in a good agreement with the measured ones for Zn, Cd and Ni, while they are underestimated for Pb and Cu, and overestimated for Co. In-situ DGT technique is recommended for the assessment of the water quality status in marine environment.

Long-term monitoring emphasizes impacts of the dredging on dissolved Cu and Pb contamination along with ultraplankton distribution and structure in Toulon Bay (NW Mediterranean Sea, France)

“…This relation is supported by a few studies which found out that the accumulated metal (including Pb) in biota are better correlated with DGT-labile fraction than with dissolved fraction (Kim et al, 2016). (Cindrić et al, 2017). It suggests a strong short-term variability of Pb concentration within the Bay, which is also obvious on temporal profiles of DGT-labile Pb concentrations (Figure 3).…”

Changes in Bacterioplankton Communities Resulting From Direct and Indirect Interactions With Trace Metal Gradients in an Urbanized Marine Coastal Area

“…Trace metals bioavailability is strongly controlled by the presence of dissolved organic ligand, especially in marine waters (Louis et al, 2009; Bruland et al, 2013). We considered here DOC concentrations and the dissolved fraction of trace metals, which is closer to the bioavailable fraction than the total concentration (Paquin et al, 2002; Cindrić et al, 2017) and consequently allow a more reliable assessment of their roles. Nevertheless, we neither evaluated the speciation of the main trace metals nor DOC composition in this study.…”

Trace Metal Contamination Impacts Predicted Functions More Than Structure of Marine Prokaryotic Biofilm Communities in an Anthropized Coastal Area

“…Additionally, labile TMs concentrations, considered to be more representative from the bioavailable fraction (Caillat et al, 2014;Han et al, 2014;Kim et al, 2016), were assessed at every site and depth using three passive samplers (diffusive gradients in thin-films -DGT) immersed for the whole survey (n = 30). DGT devices, sample preparation and analytical methods for multi-element analysis in DGT eluates were described in Cindrić et al (2017) and are summarized in Supplementary Material.…”