Polycyclic Aromatic Hydrocarbons (PAHs) and Hopanes in Plastic Resin Pellets as Markers of Oil Pollution via International Pellet Watch Monitoring

Abstract

Oil pollution in the marine environment is an unavoidable problem due to chronic input from local sources, particularly in urban areas and oil spills. Oil pollution not only causes immediate physical damages to surrounding wildlife but also some components, including higher molecular weight PAHs, can persist in the environment for many years and pose insidious threats to the ecosystem. Long-term and nontargeted monitoring of oil pollution is important. This paper examines the ability of International Pellet Watch (IPW) for initial identification and monitoring of oil pollution by analysing PAHs and hopanes in plastic pellet samples collected globally by volunteers. PAH concentrations with the sum of 28 parent and methyl PAHs vary geographically, ranging from 0.035 to 24.4 µg/g-pellet, in line with the presence or absence of local oil pollution sources, such as oil refineries or oil spill sites. This suggests that PAHs can be used to monitor petroleum pollution in IPW. A colour-coded categorization for PAH concentrations within IPW monitoring also is established to facilitate data presentation and understanding. PAH concentrations are generally higher in Western Europe, especially around the North Sea shorelines, moderate in East Asia and North America, and lower in South East Asia, Oceania, South America, and Africa. Hopane concentrations, with a smaller spatial variation (1.7-101 µg/g-pellet), showed no spatial pattern. This result and the poor correlation between hopanes and PAHs suggest that hopane concentrations alone are unsuited to identify petroleum pollution. However, hopane compositions can be used for fingerprinting sources of oil pollution. Thus, both PAHs and hopanes in IPW allow for low cost, remote monitoring of global oil pollution.

Microplastic–toxic chemical interaction: a review study on quantified levels, mechanism and implication

“…However, Southeast Asia, Oceania, South America and Africa (except for site with history of oil spillage or experiences petroleum-related activities) recorded low concentrations. For example, plastic pellets collected from Chemu Lagoon Beach located close to Tema oil refinery in Ghana was highly polluted with 2751 ng/g-pellet [193], thus confirming the influence of crude oil pollution in increasing levels of PAHs loaded on the surface of microplastics.…”

“…Mizukawa et al [113] reported PAH concentration variations of up to 2 orders of magnitude between individual countries within a region. More recently, [193] following IPW monitoring study reported that Europe at Sao Torpes Beach, Sines in Portugal (24,400 ng/g-pellet) and Forth Estuary in UK (164,900 ng/g-pellet) were highest in concentrations of total PAHs on plastic pellets collected from 75 locations in 26 countries. The authors attributed these high concentrations to crude oil pollution.…”

“…Data from the study revealed that, among the congeners, homohopanes (ranging from C 31 to C 35 ) were relatively abundant. More recently, following IPW from Western Europe, East Asia, Oceania, South America and Africa, [193] reported total hopanes level in plastic resin pellet ranged from 1700 to 101,000 ng/g which showed no spatial pattern. However, hopanes concentrations sorped on microplastics are influenced by crude oilrelated pollution.…”

“…However, hopanes concentrations sorped on microplastics are influenced by crude oilrelated pollution. Reports have indicated higher concentrations of hopanes in the Northern Hemisphere (China, Japan, UK, France, Germany, Portugal and Spain), particularly around the North Sea due to these regions having a long history of oil development and oil tanker routes [193]. Zakaria et al [194,195] pointed that crude oil origin affects the composition of hopanes and can be used for source identification of oil pollution.…”

Microplastic-Toxic Chemical Interaction: A Review Study on Quantified Levels, Mechanism and Implication

“…Studies have reported their presence on microplastics at varying concentrations of which; fluoranthene (Fluo), phenanthrene (Phe), anthracene (Anth), 3methylphenanthrene (3-MP), 9-methylphenanthrene (9-MP), 2-methylphenanthrene (2-MP), Karapanagioti et. al., 2009;Saha et al 2009;Yeo et. al., 2017).…”