Color: An Important but Overlooked Factor for Plastic Photoaging and Microplastic Formation

Qin

2023

Environ. Sci. Technol.

The global distribution of microplastics (MPs) across various environmental compartments has garnered significant attention. However, the differences in the characteristics of MPs in different environments remain unclear, and there is still a lack of quantitative analysis of their environmental sources. In addition, the inclusion of aging in source apportionment is a novel approach that has not been widely explored. In this study, we conducted a meta-analysis of the literature from the past 10 years and extracted conventional and aging characteristic data of MPs from 321 sampling points across 7 environmental compartments worldwide. We established a data-driven analysis framework using these data sets to identify different MP communities across environmental compartments, screen key MP features, and develop an environmental source analysis model for MPs. Our results indicate significant differences in the characteristics of MP communities across environments. The key features of differentiation were identified using the LEfSe method and include the carbonyl index, hydroxyl index, fouling index, proportions of polypropylene, white, black/gray, and film/sheet. These features were screened for each environmental compartment. An environmental source identification model was established based on these features with an accuracy of 75.1%. In order to accurately represent the single/multisource case in a more probabilistic manner, we proposed the MP environmental source index (MESI) to provide a probability estimation of the sample having multiple sources. Our findings contribute to a better understanding of MP migration trends and fluxes in the plastic cycle and inform effective prevention and control strategies for MP pollution.

Section: Resultsmentioning

confidence: 99%

Using Data-Driven Methods and Aging Information to Quantitatively Identify Microplastic Environmental Sources and Establish a Comprehensive Discrimination Index

Qin

2023

Environ. Sci. Technol.

“…Being superficial, the gray fraction of plastic may, in time, appear to go away while the orange fraction may, in time, appear to increase from photochemical degradation of the nurdles. Future monitoring efforts should consider this important nuance when assessing the impacts of the spill . A first estimate of the proportion of plastic types based on their color and appearance (white nurdles, orange nurdles, gray nurdles, and burnt plastic) revealed that a sizable mass of orange and gray nurdles may have been released.…”

Section: Resultsmentioning

confidence: 99%

“…Future monitoring efforts should consider this important nuance when assessing the impacts of the spill. 15 A first estimate of the proportion of plastic types based on their color and appearance (white nurdles, orange nurdles, gray nurdles, and burnt plastic) revealed that a sizable mass of orange and gray nurdles may have been released. Assessing the proportion of white, orange, and gray nurdles, and burnt plastic across time and location may provide insight about the fate of the different fractions in the environment.…”

Section: Resultsmentioning

confidence: 99%

“…While removal of the wreck is underway (estimated to be completed in 2023) and the cleanup has progressed, concerns persist about the hazardousness of the plastic. , First person accounts underscore the concern for and confusion of those whose lives have been directly impacted by the spill, e.g., fishers and beachgoers . Nonetheless, nurdles in the ocean are not new. , Past studies of oceanic nurdles have related their organic pollutant content and bioavailability, ingestion by wildlife, and degradative state to their color, suggesting that discrimination by color could resolve some of these outstanding worries. − Concerns for the plastic’s hazardousness initially drove us to examine the nurdles discussed by de Vos et al and motivated our continued in-depth analysis of them to offer further insight on the transformations undergone by the plastic. Clearly, the circumstances of the M/V X-Press Pearl maritime accident were harsher than those of earlier nurdle spills, − which led to the release of a more complex pollutant .…”

Section: Introductionmentioning

confidence: 99%

“… 10 , 11 Past studies of oceanic nurdles have related their organic pollutant content and bioavailability, ingestion by wildlife, and degradative state to their color, suggesting that discrimination by color could resolve some of these outstanding worries. 12 − 15 Concerns for the plastic’s hazardousness initially drove us to examine the nurdles discussed by de Vos et al 1 and motivated our continued in-depth analysis of them to offer further insight on the transformations undergone by the plastic. Clearly, the circumstances of the M/V X-Press Pearl maritime accident were harsher than those of earlier nurdle spills, 16 − 20 which led to the release of a more complex pollutant.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Divergent Forms of Pyroplastic: Lessons Learned from the M/V X-Press Pearl Ship Fire

et al. 2022

In late May 2021, the M/V X-Press Pearl container ship caught fire while anchored 18 km off the coast of Colombo, Sri Lanka and spilled upward of 70 billion pieces of plastic or "nurdles" (∼1680 tons), littering the country's coastline. Exposure to combustion, heat, chemicals, and petroleum products led to an apparent continuum of changes from no obvious effects to pieces consistent with previous reports of melted and burned plastic (pyroplastic) found on beaches. At the middle of this continuum, nurdles were discolored but appeared to retain their prefire morphology, resembling nurdles that had been weathered in the environment. We performed a detailed investigation of the physical and surface properties of discolored nurdles collected on a beach 5 days after the ship caught fire and within 24 h of their arrival onshore. The color was the most striking trait of the plastic: white for nurdles with minimal alteration from the accident, orange for nurdles containing antioxidant degradation products formed by exposure to heat, and gray for partially combusted nurdles. Our color analyses indicate that this fraction of the plastic released from the ship was not a continuum but instead diverged into distinct groups. Fire left the gray nurdles scorched, with entrained particles and pools of melted plastic, and covered in soot, representing partial pyroplastics, a new subtype of pyroplastic. Cross sections showed that the heat-and fire-induced changes were superficial, leaving the surfaces more hydrophilic but the interior relatively untouched. These results provide timely and actionable information to responders to reevaluate cleanup end points, monitor the recurrence of these spilled nurdles, gauge short-and long-term effects of the spilled nurdles to the local ecosystem, and manage the recovery of the spill. These findings underscore partially combusted plastic (pyroplastic) as a type of plastic pollution that has yet to be fully explored despite the frequency at which plastic is burned globally.

Enviro Toxic and Chemistry

Decadal Assessment of Microplastics, Pharmaceuticals, and Pesticides as Contaminants of Emerging Concern in Kenya's Surface Waters: A Review

Githaiga

Njuguna

Bargul

et al. 2023

Studies investigating microplastics, pharmaceuticals, and pesticides as contaminants of emerging concern (CECs) in surface water sources in Kenya are reviewed. Contaminants of emerging concern are chemicals that have recently been discovered that may pose a threat to the environment, aquatic life, and human life. Microplastics in surface waters range from 1.56 to as high as 4520 particles/m3, with high concentrations recorded in coastal waters. The dominant microplastics are fibers, fragments, and films, with foams, granules, and pellets making up only a small percentage. The main source of pharmaceuticals in water sources is not wastewater‐treatment plants but rather raw untreated sewage because high concentrations are found near informal settlements with poor sewage connectivity. Antibiotics are detected in the range of the limit of quantification to 320 μg/L, with sulfamethoxazole, trimethoprim, and ciprofloxacin being the most abundant antibiotics. The high frequency of detection is attributed to the general misuse of antibiotics in the country. A health risk assessment indicated that only ciprofloxacin and acetaminophen posed noncarcinogenic health risks in the Ndarugo River and Mombasa periurban creeks, respectively. Similarly, the detection of antiretroviral drugs, mainly lamivudine, nevirapine, and zidovudine, is associated with human immunodeficiency virus prevalence in Kenya. In the Lake Naivasha, Nairobi River, and Lake Victoria basins, frequently detected organochloride pesticides (OCPs) are methoxychlor, alachlor, endrin, dieldrin, endosulfan, endosulfan sulfate, α‐hexachlorocyclohexane (α‐HCH), γ‐HCH, and dichlorodiphenyltrichloroethane (DDT), some of which occur above permissible concentrations. The presence of DDT in some sites translates to illegal use or historical application. The majority of individual OCPs posed no noncarcinogenic health risk, except dieldrin and aldrin which had a hazard quotient >1 in two sites. Therefore, more surveying and regular monitoring in different regions in Kenya concerning CECs is essential to determine the spatial variability and effective measures to be taken to reduce pollution. Environ Toxicol Chem 2023;00:1–14. © 2023 SETAC.