Fire and Oil Led to Complex Mixtures of PAHs on Burnt and Unburnt Plastic during the M/V X-Press Pearl Disaster

Abstract

In May 2021, the M/V X-Press Pearl container ship burned for 2 weeks, leading to the largest maritime spill of resin pellets (nurdles). The disaster was exacerbated by the leakage of other cargo and the ship's underway fuel. This disaster affords the unique opportunity to study a time-stamped, geolocated release of plastic under real-world conditions. Field samples collected from beaches in Sri Lanka nearest to the ship comprised nurdles exposed to heat and combustion, burnt plastic pieces (pyroplastic), and oil-plastic agglomerates (petroplastic). An unresolved question is whether the 1600+ tons of spilled and recovered plastic should be considered hazardous waste. Due to the known formation and toxicity of combustion-derived polycyclic aromatic hydrocarbons (PAHs), we measured 20 parent and 21 alkylated PAHs associated with several types of spilled plastic. The maximum PAH content of the sampled pyroplastic had the greatest amount of PAHs recorded for marine plastic debris (199,000 ng/g). In contrast, the sampled unburnt white nurdles had two orders of magnitude less PAH content. The PAH composition varied between the types of spilled plastic and presented features typical of and conflicting with petrogenic and pyrogenic sources. Nevertheless, specific markers and compositional changes for burning plastics were identified, revealing that the fire was the main source of PAHs. Eight months after the spill, the PAH contents of sampled stray nurdles and pyroplastic were reduced by more than 50%. Due to their PAH content exceeding levels allowable for plastic consumer goods, classifying burnt plastic as hazardous waste may be warranted. Following a largely successful cleanup, we recommend that the Sri Lankans re-evaluate the identification, handling, and disposal of the plastic debris collected from beaches and the potential exposure of responders and the public to PAHs from handling it. The maritime disaster underscores pyroplastic as a type of plastic pollution that has yet to be fully explored, despite the pervasiveness of intentional and unintentional burning of plastic globally.

Chemically speciated air pollutant emissions from open burning of household solid waste from South Africa

“…Figures 5 and 6 show that EFs for HCl from rubber as well as HNO 3 from rubber, textiles, vegetation, and food discards and NH 3 from food discards were 1 to 2 orders of magnitude higher than the corresponding particulate ions. Food discards and 50 % moisture vegetation had the highest EFs for HF and particulate F − , consistent with fluorine accumulation in plants (Jayarathne et al, 2014). The modified combustion efficiencies (MCEs) for the dry (MCE = 0.88) and 20 % moisture (MCE = 0.91) vegetation samples were higher than the 50 % moisture vegetation sample (MCE = 0.79) (Wang et al, 2023).…”

“…Future study should investigate the partitioning of fluorine among gases, particles, and ashes during biomass burning. Jayarathne et al (2014) reported F − EFs in the range of 0.7-136 mg kg −1 for several types of biomass burning with an overall average of 32 ± 7 mg kg −1 . These values are in the range of dry (7.6 ± 0.6 mg kg −1 ) and 25 % moisture vegetation (17.8 ± 8.3 mg kg −1 ), but lower than the 50 % moisture vegetation (744 ± 61 mg kg −1 ) and food discards (291 ± 88 mg kg −1 ).…”

“…PAH diagnostic ratios have been used to infer PAH sources (Ravindra et al, 2008;Harner et al, 2018); however, not many ratios have been reported for MSW burning emissions (James et al, 2023). Table S3 lists several common PAH diagnostic ratios from this study.…”

Chemically Speciated Air Pollutant Emissions from Open Burning of Household Solid Waste from South Africa

“…Figures 5 and 6 show that EFs for HCl from rubber as well as HNO 3 from rubber, textiles, vegetation, and food discards and NH 3 from food discards were 1 to 2 orders of magnitude higher than the corresponding particulate ions. Food discards and 50 % moisture vegetation had the highest EFs for HF and particulate F − , consistent with fluorine accumulation in plants (Jayarathne et al, 2014). The modified combustion efficiencies (MCEs) for the dry (MCE = 0.88) and 20 % moisture (MCE = 0.91) vegetation samples were higher than the 50 % moisture vegetation sample (MCE = 0.79) (Wang et al, 2023).…”