Marine Sediments from a Contaminated Site: Geotechnical Properties and Chemo-Mechanical Coupling Processes

Francesca Sollecito,Claudia Vitone,Daniela Miccoli,Alexander M Puzrin,Federica Cotecchia,Michael Plötze

doi:10.3390/geosciences9080333

Francesca Sollecito, Claudia Vitone + Show 4 more

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https://doi.org/10.3390/geosciences9080333

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Journal: Geosciences	Publication Date: Jul 29, 2019
Citations: 12	License type: CC BY 4.0

Affiliation: Polytechnic University of Bari, ETH Zurich

Abstract

The city of Taranto in the south of Italy is one of the areas declared as “at high risk of environmental crisis” by the Italian government because it represents one of the most complex industrial sites in Europe, located near urban areas of high population density. The rich ecosystem of the Mar Piccolo basin, located at north of Taranto, started exhibiting unconfutable signs of environmental pollution, confirmed by the high concentrations of organic and inorganic contaminants. Among the different aspects involved in the environmental studies aiming at the basin remediation, this paper focuses on submarine sediments and reports some results of the geotechnical laboratory investigations which made also use of non-standard equipment and revised procedures for data interpretation in order to take account of the sediments’ contamination and heterogeneities. The geotechnical laboratory tests show that, despite the Mar Piccolo recent Holocene sediments having similar origin and composition to those of the Sub-Apennine clay basic formation, their behavioral facets appear to be altered by the presence of contaminants of both natural and anthropogenic origin. Results of washing tests are also presented as a first attempt to quantify the effects of chemo-mechanical coupling processes on the plasticity properties of the shallow sediments.

Highlights

Coastal marine environments located in areas which suffer from severe pollution due to industrial and urban development, are usually exposed to both natural and anthropogenic sources of contamination, which reflect into the alteration of properties of marine sediments
The characterization of sediments taken from site A3 will be presented, being both the deepest one and the site investigated in more detail through chemical, mineralogical and geotechnical analyses
This study represents an insight into the coupling between mechanical and chemical properties of submarine sediments from a highly-polluted site in the south of Italy

Summary

Introduction

Coastal marine environments located in areas which suffer from severe pollution due to industrial and urban development, are usually exposed to both natural and anthropogenic sources of contamination, which reflect into the alteration of properties of marine sediments. If marine pollution is defined as the introduction of substances by man into the environment, resulting in deleterious effects for humans, more in general, marine contamination is the presence of elevated concentrations of substances in the environment above the natural background level for the area [1]. Contaminants may have different origins and are classified into three categories: inorganic compounds, acid and bases, and organic compounds, with both natural and anthropic origin. The effects on the geotechnical soil properties of physical-chemical factors, such as salinity, organic and inorganic contaminants, are widely investigated in the literature.

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