MEBTRACE

Title: New methodological approach to biogeochemical studies of trace metal speciation in coastal aquatic ecosystems (MEBTRACE)

Project period: 01.09.2015 - 31.01.2020.

Total budget: 940 000 kn (~125 kEUR)

Principal Investigator: Dario Omanović, PhD

Abstract

The proposed research aims at elucidating several issues related to the physico-chemical processes governing trace metals (TM) behaviour in pristine, but also in potentially contaminated transitional and coastal aquatic ecosystems. Whether the TMs behave as micronutrients or are highly toxic to organisms, their mobility, reactivity as well as bioavailability, strongly depends on chemical speciation.

Our focus will be directed towards characterisation of interactions of TM with other macro and micro constituents of natural waters, particularly with natural organic matter, by employing jointly the most recent approaches utilizing electrochemical and hyphenated spectrometric techniques. Particular effort will be invested in the development and improvement of speciation methods, measurement protocols and sensing electrodes. Methodologies developed under controlled laboratory conditions will be verified using natural water samples and applied in on-site and in-situ field-studies. The research will lead to the establishment of sets of specific measures and criteria which will allow reliable estimation of the actual state, but also the prediction of future behaviour of TMs (speciation, mobility, bioavailability/toxicity) in case of local environmental accidents (e.g. contamination) or global threats (e.g. ”ocean acidification”).

Aquatic environments showing a variety of chemical compositions will be studied. In such conditions, variations in physico-chemical forms of the studied TMs (As, Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb, Zn) are expected to occur. Study sites will be estuarine, oxic/anoxic, eutrophic and clean/contaminated areas, in which processes occurring at the phase boundaries, as well as in the sediment and water column will be explored.

The specific subjects of the research are selected in a way to enable the outcome of the project be valuable not only to the broad scientific community working on TM speciation, but also to end-users such as ecotoxicologists or authorities managing coastal zones.

Objectives of the proposed research

The goal of the proposed research is to contribute to the knowledge in the area of development of methods/procedures for the physico-chemical speciation of trace metals (TM) in coastal waters, with the aim of better understanding of the distribution and role of TMs and their possible negative effect on the coastal water eco-system, and also in order to reveal the ecological-related effects on the coastal aquatic ecosystem produced by human activities. The research is multidisciplinary and will be based on the involvement of scientists of various expertize (analytical chemists, electrochemists, environmental chemists, oceanographers, geochemists, geologists and ecological modelers).

The team research activities will be focused on the achievement of the following specific goals:

• Quantification of the competitive interactions of various cations on the electrochemical determination of TM speciation

• Investigation and determination of the influence of seawater pH decrease („ocean acidification“) on the speciation of TM

• Improvement of the reliability of iron (Fe) determination in the seawater by the combined use of new experimental procedures and computational methods (algorithms)

• Investigation of the size-dependent distribution and speciation of TMs in the stratified estuary by employing ultrafiltration method and passive samplers (DGT)

• Improvement of the method for reliable determination of the redox speciation of chrome (Cr) by use of automated systems for on-site measurements.

• Improvement and implementation of non-toxic micro-sensors for on-site/in-situ determination of TMs

• Elucidation of major physico-chemical mechanisms and processes related to the influence of the sea and the river foam on the mobility of TMs

• Determination of the behavior of TMs during the sediment dredging and estimation of their harmful ecological influence.