Chemical adsorption of hydrophobic polycyclic aromatic hydrocarbons in the marine environment onto microplastic polymers and subsequent desorption in a simulated gut

Christopher Blair Crawford, Marie Russell, Ciaran Ewins, Brian Quinn

Research output: Contribution to conferencePaper

Abstract

With an approximate degradation time of 450 years, plastic is one of the most durable and persistent environmental contaminants in the modern world. Production since the 1950s has increased prodigiously. In the marine environment, photo-oxidative degradation and the abrasive action of waves progressively degrade larger pieces of plastic into tiny polymer particles less than 5 millimetres in diameter, termed microplastics. As a consequence of their small size, microplastics are inadvertently ingested by ocean dwelling biota, particularly susceptible filter feeders such as Mytilus edulis and many species of fish. This can result in detrimental effects such as inhibition of gastrointestinal function and feeding impairment. However, it has emerged fairly recently that microplastic polymers collected from the marine environment have been found to have Hydrophobic organic chemicals (HOCs), such as polycyclic aromatic hydrocarbons (PAHs), adsorbed onto their surface. Since marine organisms ingest microplastics, it can be proposed that microplastics have the potential to act as a transporter for the conveyance of hydrophobic persistent organic pollutants (POPs), such as PAHs, into marine biota. PAHs are formed from incomplete or inefficient combustion of organic material, diagenesis and biosynthesis. While there is a consistent background level from forest fires and volcanic activity, a significant fraction of PAHs present in the environment is due to anthropogenic activities, such as internal combustion engines. Consequently, PAHs reach the marine environment via sewage and industrial discharges, oil spillages and deposition from the atmosphere. One particular characteristic of PAHs is their susceptibility to ultra-violet light. However, pericondensed PAH structures are more centrally condensed allowing them to withstand higher ultraviolet fluxes. This results in a decrease in susceptibility to photodecomposition by ultraviolet light and thus, resistance to degradation in the marine environment. Consequently, microplastics can then adsorb these contaminants. Since many of the susceptible organisms that ingest microplastics are located at the bottom of the food chain, chemical adsorption provides a potential mechanism for the bioaccumulation of contaminants in marine organisms and the potential trophic transfer of these contaminants up the food web to larger organisms, and possibly humans. Consequently, it is necessary to investigate this potential mechanism.
Original languageEnglish
Publication statusPublished - 22 May 2016
EventSETAC Europe 26th Annual Meeting - La Cite Nantes Events Center, Nantes, France
Duration: 22 May 201626 May 2016
http://nantes.setac.eu/?contentid=851

Conference

ConferenceSETAC Europe 26th Annual Meeting
CountryFrance
CityNantes
Period22/05/1626/05/16
Internet address

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