In situ remediation of contaminated marinesediment: an overview

Abstract

Sediment tends to accumulate inorganic and persistent hydrophobic organic contaminants representing one of the main sinks and sources of pollution. Generally, contaminated sediment poses medium- and long-term risks to humans and ecosystem health; dredging activities or natural resuspension phenomena (i.e., strongly adverse weather conditions) can remobilize pollution releasing it into the water column. Thus, ex situ traditional remediation activities (i.e., dredging) can be hazardous compared to in situ techniques that try to keep to a minimum sediment mobilization, unless dredging is compulsory to reach a desired bathymetric level. We reviewed in situ physico-chemical (i.e., active mixing and thin capping, solidification/stabilization, chemical oxidation, dechlorination, electrokinetic separation, and sediment flushing) and bio-assisted treatments, including hybrid solutions (i.e., nanocomposite reactive capping, bioreactive capping, microbial electrochemical technologies). We found that significant gaps still remain into the knowledge about the application of in situ contaminated sediment remediation techniques from the technical and the practical viewpoint. Only activated carbon-based technologies are well developed and currently applied with several available case studies. The environmental implication of in situ remediation technologies was only shortly investigated on a long-term basis after its application, so it is not clear how they can really perform.

Effect of biostimulation treatments on the toxicity of oil-contaminated mangrove sediment

“…In order to avoid such impacts, cleaning strategies have been put in place with the aim of restoring oil-polluted sediments (Lofrano et al, 2017). Mechanic strategy as dredging and capping strategy usually employed in flat areas are not viable in mangroves due to complex vegetation that is found in this environment (Lofrano et al, 2017). Thus alternative approach, as bioremediation, should be required.…”

“…Bioremediation strategies rely on biological potential to degrade (e.g., microbial degradation) and/or remove (e.g., phytoremediation) hydrocarbons present in the sediment (Dowty et al, 2001;Mills et al, 2003), causing lower impact than the use of physical structures for oil removal (Cantagallo et al, 2007). Among such strategies we highlight natural attenuation (self cleaning of the mangrove without human interference), bioaugmentation (addition of microorganisms to the impacted environment) and biostimulation (correction of the nutrient concentrations to stimulate growth of the microbiota) (Lofrano et al, 2017;Yu et al, 2005).…”

Toxicity Effects of Functionalized Quantum Dots, Gold and Polystyrene Nanoparticles on Target Aquatic Biological Models: A Review

“…NPs have recently attracted an enormous attention because of their potential applications in chemical, catalytic, electronic, optical, mechanical, magnetic and medical fields [ 4 , 5 , 6 ] and most of them are considered non-toxic, bio-safe and have been extensively used as drug carrier cosmetics, fillings in medical materials, antimicrobial materials, and contaminated land and sediment remediation agents [ 7 ].…”

Organotin compounds in marine sediment: Detection and concerns

“…As a result, BT levels in coastal environments have been decreasing worldwide (Sousa et al, 2007;Rato et al, 2009). However, high levels of BTs are still detected in a variety of aquatic organisms and are found in water and sediment from estuaries and harbours (Leung et al, 2006;Berto et al, 2007;Lofrano et al, 2016;Lofrano et al, 2017). Thus, the environmental occurrence and adverse health effects of BTs on marine organisms are still of concern.…”